. Eng... · Mech. Eng. Sci. J. Vol. No. pp. Skopje 37 1–2 1–120 2019 Маш. инж. науч....

UDC 621 CODEN: MINSC5 ISSN 1857 – 5293

e: ISSN 1857 – 9191

MECHANICAL ENGINEERING SCIENTIFIC JOURNAL

МАШИНСКО ИНЖЕНЕРСТВО

НАУЧНО СПИСАНИЕ

Volume 37 Number 1–2 Skopje, 2019

Mech. Eng. Sci. J. Vol. No. pp. Skopje

37 1–2 1–120 2019 Маш. инж. науч. спис. Год. Број стр. Скопје

MECHANICAL ENGINEERING – SCIENTIFIC JOURNAL

МАШИНСКО ИНЖЕНЕРСТВО – НАУЧНО СПИСАНИЕ

Published by Faculty of Mechanical Engineering, Ss. Cyril and Methodius University in Skopje, Republic of Macedonia

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MECHANICAL ENGINEERING – SCIENTIFIC JOURNAL

FACULTY OF MECHANICAL ENGINEERING, SKOPJE, REPUBLIC OF MACEDONIA

МАШИНСКО ИНЖЕНЕРСТВО – НАУЧНО СПИСАНИЕ

МАШИНСКИ ФАКУЛТЕТ, СКОПЈЕ, РЕПУБЛИКА МАКЕДОНИЈА

Mech. Eng. Sci. J. Vol. No. pp. Skopje

37 1–2 1–120 2019 Маш. инж. науч. спис. Год. Број стр. Скопје

TABLE OF CONTENTS (С О Д Р Ж И Н А)

PRODUCTION ENGINEERING

(Производно машинство)

613 – Katerina Dimovski, Gligorče Vrtanoski

DEVELOPMENT OF THE ENERGY MANAGEMENT INFORMATIVE SYSTEM

(Развој на информациски систем за управување со енергија) ....................................... 5–15

614 – Taško Smileski, Gligorče Vrtanoski

DEVELOPMENT OF INNOVATIVE BRAKE SYSTEM FOR ROLLING STOCK

(Развој на иновативен сопирачки систем за железнички превозни средства) ............ 17–27

615 – Andon Naskovski, Gligorče Vrtanoski

TOTAL PRODUCTIVE MAINTENANCE – TOOL TO IMPROVE

THE COMPANIES PERFORMANCE

(Целосно продуктивно одржување – алатка за подобрување на перформансите

на компаниите) .................................................................................................................. 29–40

616 – Elena Papazoska, Gligorče Vrtanoski

SIX SIGMA METHODOLOGY – TOOL FOR IMPROVING THE CAPABILITY

OF THE PRODUCTION PROCESS

(Mетодологијата шест сигма – алатка за подобрување на способноста

на процесот на производството)...................................................................................... 41–54

617 – Vesna Gjorčeva, Gligoče Vrtanoski

PROCESSES OPTIMIZATION AND REDUCTION OF OPERATIONAL COSTS

– CASE IN INSURANCE COMPANY

(Оптимизација на процесите и намалување на оперативните трошоци

– Случај во осигурителна компанија –) .......................................................................... 55–64

618 – Georgi Hristov, Gligorče Vrtanoski

MANAGING ORGANIZATIONAL CHANGE IN COMMUNAL PUBLIC

ENTERPRISES: – A LITERATURE REVIEW

(Управување со организациските промени во комуналните претпријатија:

Преглед на литературата–) .............................................................................................. 65–70

MECHATRONIC

(Механотроника)

619 – Simona Domazetovska, Hristijan Mickoski, Marjan Djidrov

KINEMATIC MODELLING AND ANALYSIS OF SERIAL MANIPULATOR

(Кинематско моделирање и анализа на сериски манипулатор) ................................... 71–77

620 – Maja Anačkova, Hristijan Mickoski

CAD modelling of parallel robot (tripod) in Matlab/Simulink

(CАD-моделирање на паралелен робот (трипод) во Matlab/Simulink) ........................ 79–86

ENERGY EFFICIENCY

(Енергетска ефикасност)

621 – Dame Dimitrovski, Dalibor Stojevski

LIFECYCLE COSTS COMPARATION BETWEEN DISTRICT HEATING

AND INDIVIDUAL GAS HEATING

(Споредба на трошоците во текот на работниот век на системот на централно

греење и индивидуалното греење со гас) ....................................................................... 87–91

THERMAL ENGINEERING

(Термичко инженерство)

622 – Filip Mojsovski

DRYING CONDITIONS FOR PADDY PROCESSING IN MIXED-FLOW HIGH-

CAPACITY PLANT

(Услови на сушење за третман на оризова арпа во индустриска сушилница

со комбинирано струење) ................................................................................................ 93–98

DESIGN AND CONSTRUCTION OF STRUCTURES

(Дизајн и конструкција на структури)

623 – Bojana Trajanoska, Elisaveta Dončeva, Daniela Pana, Hristijan Gjorgievski

CONCEPT FOR STUDENT GLASS PAVILION

(Концепт за студентски стаклен павилјон) .................................................................. 99–105

INDUSTRIAL DESIGN

(Индустриски дизајн)

624 – Nikola Gerasimovski, Elena Angeleska, Sofija Sidorenko

BIONIC PRINCIPLES OF SPACE OPTIMIZATION APPLIED

IN THE PRODUCT DESIGN PROCESS

(Бионички принципи за оптимизација на просторот применети

во процесотна дизајнирање) ....................................................................................... 107–115

Instruction for authors .......................................................................................................... 117–120

Mechanical Engineering – Scientific Journal, Vol. 37, No. 1, pp. 5–15 (2019)

Number of article: 613 ISSN 1857–5293

CODEN: MINSC5 e-ISSN 1857–9191

Received: May 20, 2018 UDC: 005.5/.6:004.75]:620.91

Accepted: July 15, 2018

Original scientific paper

DEVELOPMENT OF THE ENERGY MANAGEMENT INFORMATIVE SYSTEM

Katerina Dimovski1, Gligorče Vrtanoski2

1MAKSTIL AD Skopje, Duferco Group,

16 Makedonska brigada, No. 18, 1000 Skopje, Republic of N6rth Macedonia 2Faculty of Mechanical Engineering, "Ss. Cyril and Methodius" University in Skopje,

Karpoš II bb, P.O. box 464, 1001 Skopje, Republic of N6rth Macedonia

[email protected]

A b s t r a c t: The Industrial Revolution initiates an era of mass production and industrialization of cities that

provides all the comforts of modern living, and thus the unconscious pollution of the planet, climate change and global

warming. According to the Goddard Institute of Space Studies (GISS) of the National Aeronautics and Space Agency,

the depths in the ozone layer and the increased carbon dioxide emissions in the air are responsible for increasing the

surface temperature of the Earth by 1 °C in the last 100 years. As temperature rises on the Earth, we face an increase

of sea level levels, a change in precipitation on a regional scale, frequent extremes in temperatures like heat waves,

droughts, floods and snowstorms. The warming is felt more on the land surface than in the sea waters, while the most

significant is the Arctic, where glaciers are starting to disintegrate, and this can lead to the eradication of some species

of flora and fauna. For the human, global warming will lead to the challenge of providing food and leaving populated

areas close to flooded areas. Many countries support the climate change convention and contribute to reducing the

impact of GTC with climate engineering, with global warming being stopped before reaching 2 °C compared to the

period before industrialization. By implementing a system for managing energy and renewable energy sources, it will

contribute to the rational utilization of energy and energy sources and the formation of a sustainable society that will

affect in future reduction of carbon dioxide emissions in the atmosphere.

Key words: EnMS – energy management system; self-sustaining facilities; management of processes;

energy efficiency; EMIS – energy management informative system

РАЗВОЈ НА ИНФОРМАЦИСКИ СИСТЕМ ЗА УПРАВУВАЊЕ СО ЕНЕРГИЈАТА

А п с т р а к т: Со индустриската револуција започнува ерата на масовно производство и индустријали-

зација на градовите, што ги овозможува сите удобности на модерното живеење, а со тоа и несвесно загадување

на планетата, климатските промени и засилување на ефектот на стаклена градина. Според Институтот Годард

за вселенски истражувања на НАСА, за зголемување на температурата на површината на Земјата за 1°C во

последните 100 години се одговорни дупките во озонската обвивка и зголемената емисија на јаглероден диок-

сид во воздухот. Со зголемување на температурата на Земјата се соочуваме и со пораснување на нивото на

водите во морињата, промена во врнежите и сушните периоди на регионално ниво, фреквентни екстреми во

температурите како топлотни бранови, суши, поплави и снежни бури. Затоплувањето се чувствува повеќе на

копнената површина отколку во морињата, а најзначајно е на Арктикот каде глечерите полека се топат, а тоа

може да доведе до исчезнување на некои видови флора и фауна. За човечката раса глобалното затоплување ќе

доведе до предизвик за обезбедување храна и до напуштање населени места блиску поплавните подрачја.

Многу земји ја поддржуваат конвенцијата за климатски промени и со климатски инженеринг го даваат својот

придонес за намалување на ефектот на стаклена градина, со што глобалното затоплување ќе биде стопирано

пред да достигне 2°C во споредба со прединдустрискиот период. Со имплементирање на системите за

менаџирање со енергенси и обновливи извори на енергија ќе се придонесе за рационално искористување на

енергијата и енергенсите и формирање на одржливо општество, што пак во иднина ќе влијае врз намалување

на емисијата на јаглероден диоксид во атмосферата.

Клучни зборови: EnMS– систем за менаџирање со енергенси; самоодржливи објекти; управување со про-

цеси; енергетска ефикасност; ЕМIS – информативен систем за менаџирање со енергенси

6 K. Dimovski, G. Vrtanoski

Mech. Eng. Sci. J., 37 (1–2), 5–15 (2019)

1. INTRODUCTION

Advancement in technology used in everyday

life for transportation and manufacturing leads to

rapid increasment in energy consumption. Natural

supplies of high calorie coal are reduced day by day.

The life on this planet is not self-sustainable to sup-

port the burden of modern society, and in order not

to affect the quality of this lifestyle, it is urgent to

rationalize the usage of energy. This means saving

energy for production by implementing Energy

Management Systems (EnMS), as well as control-

ling energy consumption in real time.

EnMS will not only save energy for produc-

tion, but also will make the consumer more inde-

pendent from the supplier of energy and continuous

fluctuations and increasment on the market prices.

When building new production plants or build-

ings it is essential to incorporate energy strategy and

efficiency predictions for future energy use. In the

existing buildings and industry plants it is important

to make adjustments to incorporate energy efficient

methodologies by making investments and process

optimization that will lead to better use of energy.

The making of EnMS, the implementatiot and

successful maintenance is complicated process that

needs intradisciplinary professionals and experts in

process automation and machine engineering, as

well as sales and marketing.

2. LITERATURE REVIEW

As relatively new software tool, EnMS has

high research potential in the development and in

improving companies’ performance and productiv-

ity [1, 2, 3, 6, 9]. In the improvement of overall com-

pany business strategies, EnMS uses informations

and innovation integration for lowering the foot-

print in carbon trust of the company.

Base of this concept is energy management,

that is elaborated in numerous books, reports and re-

searches [3, 11, 12].

According to the many surveys, enough data

have been collected that can be analyzed with few

error options, leading to reliable sources of the

structure and benefits of the EnMS energy manage-

ment system. For the purpose of developing the

model / prototype of the EnMS system, a manual [4,

10, 13] for managing energy is used as a reliable

source that informs about the analysis, the technical

and economic aspects of the heating and air condi-

tioning systems, the control systems and automati-

on, lighting, air quality control, energy maintenan-

ce, control over the procurement of energy sources,

as well as for the procedure for measurement and

verification of energy savings [4, 6, 10, 13].

The researchers generally agree on the benefits

EnMS can provide. There are two types of energy

management systems. The first type is EMIS infor-

mation system for energy management monitors

and monitors energy consumption in a defined unit

(hourly, daily, monthly, etc.) [14, 15, 16] and ex-

ports reports and analyses regarding energy con-

sumption. The second type, EnMS the energy man-

agement system continuously monitors consump-

tion and allows for real-time corrective measures

that will affect consumption [17, 18, 19].

3. MODEL OF THE ENERGY MANAGEMENT

SYSTEM

In the sphere of innovation, the energy man-

agement system is one of the leading trends of the

21st century. Every facility, company and industry

that strives to protect the environment and reduce

greenhouse gas emissions as well as energy and en-

ergy savings will inevitably implement such a sys-

tem. Energy Management System (EnMS) allows

the planning and management of energy at hourly

level [7], with each information coming to the top

management of the company in the form of reports.

For successful implementation of the EnMS

system for reducing consumption, it is first neces-

sary to create an energy efficiency policy that will

be supported by all employees. Next, it is necessary

to determine the limits in which the company can

influence the consumption of energy and energy

sources. It implies whether all production units are

locally compact or have production plants in differ-

ent locations.

Subsequently, it is necessary to identify the

main consumers of energy and energy sources. In

each plant, one can determine which are the main

consumers such as electricity, oxygen, compressed

air, water and other energy sources, and each of

those consumers should be placed on the optimiza-

tion list [5, 8].

In order to achieve the desired energy and en-

ergy savings, a constant review of the results and

actions taken in the production process is required.

Minor improvements in the production process it-

self lead to major changes that are almost always in

Development of the energy management informative system 7

Маш. инж. науч. спис., 37 (1–2), 5–15 (2019)

the direction of savings in materials, energy and en-

ergy sources, and thus increased profits of the com-

pany.

With proper knowledge of the production it is

necessary to perform optimization of the process

and the plants. This is not a simple job at all. Care

should be taken not to disturb the quality of the fin-

ished product. It is necessary for the sector for com-

merce and procurement in the future to strive for en-

ergy efficient parts for which only the purchase

price will not be important, but also to include cal-

culations for energy consumption and ongoing

maintenance. If in the part of purchases focuses only

on an initially lower cost of an energy-inefficient

system, over time it will be spent much more than if

an energy-efficient part or device would be pur-

chased which would be an investment that would

soon be repaid taking the energy price who con-

sumes it.

In order to see the results of the EnMS system

for energy management, it is necessary to constantly

check the energy and energy consumption and to re-

view the possibilities for continuous improvement.

3.1. Creating a model

For the conceptualization of a model for en-

ergy and energy management, it is necessary to set

control metering devices for measurements of the

consumption of electricity at the measuring points

that provide data on consumption and on which fur-

ther calculation of the payment is made. Each of the

measuring devices is required to provide data on ac-

tive energy, reactive energy, maximum power and

power factor as characteristics of the electrical en-

ergy transmission system [21].

Appropriate exits of the measuring devices are

collected in a device called a concentrator, which

serves as a collector of output impulses from the

measuring devices. The collected impulses are con-

verted into digital data that connect to the internal

database through a computer network and are trans-

ferred to the company's main computer center, that

is to the central computer servers. Different net-

working principles for control metering devices, the

concentrator and the computer server are shown in

Figure 1.

Fig. 1. An example of a network connection to an energy management model EnMS with SCADA [21]


Mech. Eng. Sci. J., 37 (1–2), 5–15 (2019)

In the case where the measuring devices are at

a great distance from the computer server, data com-

puter servers connected to a WLAN / GPRS modem

must be set up for remote reading of the values of

the measuring devices.

The creation of a model for energy manage-

ment can be created in 4 phases [21, 22]:

1. In the first phase of the development of the

model, ideas are generated from all employees

covering this issue.

2. Then, the second phase of the concept mode-

ling, which focuses on the research of the

current state, possibilities for implementation

of the envisaged system, is followed, and the

ideas for innovations from different aspects are

considered.

3. In the third phase, a completely new one can

be developed, or existing computer software

can be adapted to enable the existing measu-

rement devices to be connected, or new mete-

ring devices can be installed in pre-selected

key sites that have significant energy and ener-

gy consumption.

4. The fourth and final phase of the model pro-

vides for a correct nomination of the basic

energy and energy consumption and moni-

toring the consumption of energy and energy

sources for the current hour. To this end it is

necessary to set monitors for supervision in all

production facilities and to train persons who

will further monitor the consumption of energy

and energy sources directly from the monitor

display and will react in real time according to

the prescribed operating instructions and pro-

tocols of the company.

In order to begin with the concept of EnMS, it

is necessary to know and select the significant con-

sumers and which energy sources they use. It is nec-

essary to place on the incoming energy sources

measuring devices that will read the consumption in

real time in accordance with the rules for the energy

and energy sources at the energy market.

After the installation of the measuring devices,

the software development phase is adapted for the

needs of the dynamic process in all production

plants in the company. The software allows to mon-

itor the consumption of all energy sources that are

connected in the energy and energy sources man-

agement system EnMS.

Each system is unique and tailored according

to the production process and no single universal

EnMS system can be made.

4. OPERATIONAL USE OF THE DEVELOPED

MODEL FOR ENERGY MANAGEMENT

Real-time energy management is a modern

technology that transforms the way of utilizing and

supplying energy by continuously collecting data on

consumption and tracking past performances. These

data are analyzed using the methodology for calcu-

lation of energy consumption and as a result, opti-

mization of propulsion consumption is obtained

[20].

Sensors, measuring devices, protocols and

other equipment that provides data in the system da-

tabase (Figure 2), which then through analyses and

other services shows the performance of the object

in real time. As an output, the system can issue a

recommendation to improve performance in real

time, resulting in lower operating and service costs

and the ability to limit consumption and maintain

productivity [22].

Fig. 2. An example of connecting the energy management system EnMS [22]

4.1. Methodology for calculation of energy savings

The first step of calculation energy savings is

collection of data from the quantity of final product

produced and the energy used for its production.

The report is generated from the company's infor-

mation system (ERP). For the input parameters in

the regression analysis used for the formation of an

energy model, is the energy consumption of all ma-

chinery of the production process. As input are


Маш. инж. науч. спис., 37 (1–2), 5–15 (2019)

taken into consideration product specifications that

affect consumption such as [22]: production activi-

ties, weather conditions, winter and summer regime

of lighting and some routine variables that are mea-

surable as shown in Table 1.

T a b l e 1

Results of the calculation of energy consumption with mathematical regression model [22]

(K0) (K1) (K2) (K3) (K4) (K5) (K6) (K7) (K8) (K9) (K10) (K11)

Production

units

Energy

(MWh)

Predicted

consumption

(MWh)

EnPI

Actual

savings

(MWh)

Sum of actual

savings (MWh)

Target

(MWh)

Target

savings

(MWh)

Cum sum of

target savings

(MWh)

Price € Savings €

Jan-15 20.200 850.320 0

Feb-15 20.469 801.359

Mar-15 20.737 806.434

Apr-15 21.006 811.509

May-15 21.274 816.583

Jun-15 21.543 821.658

Jul-15 21.811 826.733

Aug-15 22.080 831.807

Sep-15 22.349 836.882

Oct-15 22.617 841.957

Nov-15 22.886 847.031

Dec-15 21.543 852.106 0 0

Jan-16 23.423 813.250 815.189 0,03 -1.939 -1.939 809.184 -6.005 -6.005 406.625 -9.695

Feb-16 23.691 800.370 812.270 0,03 -11.900 -13.838 796.368 -15.901 -21.907 400.185 -59.498

Mar-16 23.960 808.340 809.350 0,03 -1.010 -14.849 804.298 -5.052 -26.958 404.170 -5.050

Apr-16 24.229 806.100 806.431 0,03 -331 -15.179 802.070 -4.361 -31.320 403.050 -1.653

May-16 24.497 802.111 803.511 0,03 -1.400 -16.579 798.100 -5.411 -36.730 401.056 -7.001

Jun-16 24.766 797.592 800.592 0,03 -3.000 -19.579 793.604 -6.988 -43.718 398.796 -14.999

Jul-16 25.034 787.622 797.672 0,03 -10.050 -29.630 783.684 -13.988 -57.707 393.811 -50.252

Aug-16 25.303 784.833 794.753 0,03 -9.920 -39.550 780.909 -13.844 -71.551 392.417 -49.600

Sep-16 25.571 780.340 791.834 0,03 -11.494 -51.043 776.438 -15.395 -86.946 390.170 -57.468

Oct-16 25.840 760.914 788.914 0,03 -28.000 -79.043 757.109 -31.805 -118.751 380.457 -140.000

Nov-16 26.109 765.955 785.995 0,03 -20.040 -99.083 762.125 -23.869 -142.620 382.978 -100.198

Dec-16 26.000 698.150 787.175 0,03 -89.025 -188.108 694.659 -92.516 -235.136 349.075 -445.124

Jan-17 26.000 786.756 787.175 0,03 -418 -188.526 782.823 -4.352 -239.488 393.378 -2.092

Feb-17 26.914 780.775 777.236 0,03 3.539 -184.987 776.871 -365 -239.853 390.388 17.693

Mar-17 27.183 774.794 774.317 0,04 477 -184.511 770.920 -3.397 -83.921 387.397 2.384

Apr-17 27.451 768.812 771.398 0,04 -2.585 -187.096 764.968 -6.429 -98.075 384.406 -12.926

May-17 27.720 762.831 768.478 0,04 -5.647 -192.743 759.017 -9.461 -112.229 381.415 -28.236

Jun-17 27.989 756.850 765.559 0,04 -8.709 -201.452 753.065 -12.493 -126.382 378.425 -43.545

Jul-17 28.257 750.868 762.639 0,04 -11.771 -213.223 747.114 -15.525 -140.536 375.434 -58.855

Aug-17 28.526 744.887 759.720 0,04 -14.833 -228.056 741.162 -18.557 -154.690 372.443 -74.165

Sep-17 28.794 738.905 756.800 0,04 -17.895 -245.951 735.211 -21.589 -225.951 369.453 -89.475

Oct-17 27.720 732.924 768.478 0,04 -35.554 -281.505 729.259 -39.219 -261.505 366.462 -177.770

Nov-17 24.720 726.943 801.089 0,03 -74.146 -355.651 723.308 -77.781 -350.620 363.471 -370.730

Dec-17 25.720 726.943 802.069 0,03 -75.126 -430.777 723.308 -78.761 -420.777 363.471 -375.631

Jan-18 29.869 745.123 average 384.539 -2.153.887

Feb-18 30.137 742.203

Mar-18 30.406 739.284

Apr-18 30.674 736.364

May-18 30.943 733.445

Jun-18 31.211 730.526

Jul-18 31.480 727.606

Aug-18 31.749 724.687

Sep-18 32.017 721.767

Oct-18 32.286 718.848

Nov-18 32.554 715.928

Dec-18 32.823 713.009


Mech. Eng. Sci. J., 37 (1–2), 5–15 (2019)

Table 1 shows the calculated energy savings

results using the regression model in the time frame

for which the analysis is performed. In Table 1,

2015 is taken as the base year through which the im-

plementation of EnMS takes place. The next two

years, 2016 and 2017, are the years on which the

mathematical model is formed, and the predictions

are made on the basis of the planned production for

2018.

The first column (K1) represents the unit value

of the final product expressed in pieces, tons, liters,

depending on how the company calculates the final

product, while the second column (K2) represents

the amount of electricity in MWh consumed in the

production.

The predicted energy consumption (K3) is the

output of the regression analysis that is the sum of

the intersection with the coefficients multiplied by

the corresponding input parameter, as shown in the

third column (K3), and represents the frame in

which the consumption should vary. Calculated val-

ues of predicted consumption are shown in column

3 (K3) and together with the energy consumed (K2)

construct the graph shown in Figure 4.

The fourth column (K4) in Table 1 represents

the energy performance coefficient, which gives the

percentage of the expected consumption versus re-

alized consumption. The fifth column (K5) repre-

sents the real savings from the regression model and

the consumed energy where it can be noted how

much MWh are saved monthly. The sixth column

(K6) represents a cumulative amount of savings

over the period.

Target savings (K8) derrives from the mathe-

matical regression model and shows how much

MWh should be spend monthly according to the

planned production, in order to achieve the desired

savings, that in this case is 3% savings already cal-

culated in the results.

The last columns represent the savings ex-

pressed in a monetary unit, that is to say the cost of

the energy in euros (K10) and the monthly saving of

MWh expressed in euros (K11).

The difference between the anticipated (K3)

and the realized consumption (K2) is discussed fur-

ther with the team and the reasons for the specific

deviations are analyzed.

The actual savings column (K5) represents the

difference from the planned consumption (K3)

according to the mathematical model and the actual

consumption (K2) according to the measured valu-

es. The purpose of the formed model is to produce

a monthly target-savings (K8) of a certain percen-

tage (in the model of Table 1 it is 3%), which should

be regulary checked during production. This per-

centage is not fixed and is part of the company's

energy saving policies and can vary on annual basis.

To change the target savings (K8), the calculated

formula changes the predicted percentage and auto-

matically generates the monthly targeted savings

that needs to be achieved.

The last two columns (K10) and (K11) show

the monthly price of electricity expressed in euros

for a large industrial consumer.

According to the energy strategy, the company

sets annual target savings that needs to be achieved.

According to target consumption (K7) and savings

(K8), the long-term goals in line with the energy

policy are followed, the potential targets and invest-

ments for energy savings in the next year are

updated and action plans are being set up. Company

policy should aim at energy efficient maintenance

of significant energy users through maintenance

training, monitoring of critical operating parame-

ters, plan for effectively planned maintenance and

employee awareness of their impact on the energy

consumption on each significant user.

4.2. Use of the developed model

The first step of the monitoring the energy us-

age is completed with the implementation of the

EnMS system. The next step is managing energy,

which means real time monitoring and managing

consumtion of each siginificant energy user.

Every company needs to know the significant

energy users and the type of energy they use in the

production process, since the initial optimization

starts with them. The other less significant consum-

ers have a lower priority in the process of introduc-

ing energy efficiency principles [22]. For example,

in a large manufacturing industry, it is insignificant

if the lighting in the halls is completely replaced

with efficient solutions, if the motors or boilers are

inefficient, while in office facilities, lighting is an

important factor.

With the formulated regressive model for each

consumer, a consumption plan for the next year can

be determined and calculated whether the plant is

energy efficient despite of the production. From the

results obtained with the conducted mathematical

regression analysis and from the developed models

of energy performance, a plan for consumption for

the next period can be formed. For future energy

consumption forecasts according to the planned


Маш. инж. науч. спис., 37 (1–2), 5–15 (2019)

production quantity, energy managers can choose to

set the target so it will achieve the best performance

of the previous year or choose a fixed savings of a

certain percentage. In the case of fixed savings

(K9), the percentage is entered in the creation of the

model and consumption is required to follow the

trend of the model. In case when the consumption

(K3) is less than (K8), energy savings are made

which in the real case are shown in (K9), and in case

the actual consumption (K2) is above the trend of

the model, the plant consumes more than planned,

there is a loss of energy and in that case where it is

necessary to intervene, which means corrective ac-

tion needs to be taken.

The savings resulting from Table 1 columns

(K6) and (K9) are shown in the following graph

(Figure 3) from which it can be concluded that to a

certain point the amount of target savings (K9)

(shown in red trend line) and the amount of the ac-

tual savings (K6) (shown by the blue trend line) are

followed by which period the efficiency of the plant

increases and the actual savings exceed the planned

savings [22].

The graph shown in Figure 3 refers to the sav-

ings shown in Table 1. The time period is two years,

i.e. 24 months, from 2016 to 2017 [22].

According to the data from Table 1, for the

specific mathematical regression model and analy-

sis of the consumed energy according to the produc-

tion, it can be noted that the return on the initial in-

vestment for a period of 6 months. As an initial in-

vestment, the data from Table 1 and the cost of en-

ergy with EnMS were taken.

Fig. 3. Graphic representation of the savings achieved with EnMS [22]

Fig. 4. Regressive models of calculation of consumption and future prediction [22]


Mech. Eng. Sci. J., 37 (1–2), 5–15 (2019)

On the basis of the obtained results from Table

1 and the calculated consumption (K3), the regres-

sive models shown in Figure 4 are formed, where

the dashed line (shown in red) represents the predic-

ted energy consumption (K3), while the full trend

line (shown by blue color) represents the actual

consumption (K2). From the analysis of the results

and the graph, it can be noted that by January 2017

the real consumption is lower than planned, which

means that everything is in accordance with the

energy policy, the promoted energy practices and

procedures of the company are satisfied.

In the second month of 2017, it can be noted

that consumption is greater than anticipated, which

can be influenced by several factors and it is neces-

sary to consider that month specifically and directed

to the quality of operations. On the basis of this

principle, consumption prediction can be performed

when the planned quantity of product units is known

for a certain period of time [22].

5. COMPARATIVE ANALYSIS

OF THE RESULTS OBTAINED

WITH THE DEVELOPED MODEL

The energy management system is a signifi-

cant investment. While there is an opportunity for

the company to directly implement ready-made so-

lutions for EnMS, but it can also develop and adapt

software. Given the quantities produced on the final

product, the price for transmission, distribution and

balancing of the energy can be rounded up to a

monthly savings of around 10%. This entails a re-

turn on investment in less than a year [22].

With operational control in the production pro-

cess and taking into account the minimum invest-

ment for the energy management system, depending

on the dynamics of the production process, in some

industries, the investment for EnMS can also be

paid for a shorter period of operational operation. If

the user spends an average of 40 MWh (shown in

Table 2, column (K2)) with an appropriate day

ahead nomination of energy, one can significantly

affect the cost per MWh. By nominating an upper

limit on consumption in moments when the stock

exchange of energy is more expensive than the price

of the trader or the nomination of the lower limit of

consumption in the period when the price of the

stock exchange is significantly lower than the

trader, there are large variations in the cost of pro-

duction for the final product.

For industries that are dominant electricity

consumers, this model represents a negligible in-

vestment leading to large energy savings. A key role

in the success of the EnMS model is the system for

predicting the consumption or expertise of the team

working with the nomination. The members of the

team should be adequately familiar with the produc-

tion process and the dynamics of foreign exchange

markets for the electricity market, because any

wrong forecast and estimate is a loss, and any good

prediction leads to a reduction in the unit cost price

and the competitiveness of the company's market

[22].

Table 2 gives the energy consumed for the

current hour (K2), the announced energy (K3) and

(K4) and an example of the prices of electricity from

the stock exchange in two days (K5) and (K6) for

the analysis of 46th week of the year. From the data

in Table 2, it can be concluded that one precisely

predicted day is enough to pay off the investment of

the EnMS system in relation to the received cost of

consuming the consumed electricity [22].

For medium and small consumers, it may be

necessary to have a longer period of time to see the

positive effects and savings from such an advanced

model of EnMS for monitoring and managing the

consumption of energy.

Depending on the variations in the price of the

stock exchange at the hourly level as shown in Table

2, fewer can be announced, and a larger amount of

energy is taken. In that case, when the price of the

free market is lower than the trader, a reduction in

the cost per unit of MWh is taken. With the EnMS

model in these days, more than 50% of the energy

cost can be saved. But there are days when the price

of electricity on the market is greater than the one

offered by the trader. In those days it is necessary to

announce the upper limit of consumption and take a

minimum amount of energy from the free market.

Table 2 shows the data for each hour of con-

sumed energy (K1), standard consumption (K2) and

an example of two announcements of the energy

supply from a trader (K3) and (K4). The price of-

fered by the merchant is fixed for each day of the

month, while the price of electricity on the free mar-

ket varies at hourly level. Without an EnMS moni-

toring system (Table 2, Columns (K8) and (K9)),

daily nominations will be a significant challenge.

Total expressed energy consumed (K2) which

is taken to calculate one day is approximately 900

MWh. For fixed power consumption at a given

hour, different amounts of energy (K3) and (K4) can

be nominated, which will give different values in

the formation of the final energy price shown in the

columns (K8) and (K10). The same applies to the

columns (K9) and (K11) for a different value of the


Маш. инж. науч. спис., 37 (1–2), 5–15 (2019)

free market price (K7), which on that day is signifi-

cantly higher than the price of the trader. Without

the EnMS model, there is a significant difference in

the value of the funds spent with respect to the use

of the EnMS model (Table 2, columns (K10) and

(K11)).

It is significant that using the EnMS model

saves the company's financial resources (Table 2,

Columns (K9) and (K11)) and when the team has a

poor forecast or announcement (K4).

T a b l e 2

Overview of the nomination of consumption with and without the energy management system EnMS [22]

Figure 5 shows a graphic representation of the

price of electricity for hourly production of final

product. It is significant to notice the variation in the

price of energy for the same quantity of produced

final product.

Figure 6 shows the quantity of nominated en-

ergy and real consumption of electricity hourly. The

nominated energy is charged at the price given by

the trader, while the remaining energy is taken from

the market. In days when the price of energy from

the stock is lower than that of the trader, it is desir-

able to nominate a smaller amount of energy, while

in periods when the price of the trader is lower, it is

desirable to nominate a greater amount of energy to

reduce the cost of production of a unit product.

Figure 7 shows the difference in the cost price

needed for the production of a unit product. For the

production of a single product, the price may vary

considerably. One influential factor is the price of

electricity in the market for a certain hour, then the

nomination, i.e, the amount of electricity that is

taken from the trader and the rest from the market.

The most important factor for increasing the savings

of the company is the EnMS energy management

system, which monitors the consumption in real

time and can minimize the negative effects of the

market prices. Without the developed model of

EnMS, from Figure 7 it can be easily assessed and

realized that the price of the product is twice as high.


Mech. Eng. Sci. J., 37 (1–2), 5–15 (2019)

Fig. 5. Price for hourly production expressed in euros [22]

Fig. 6. The nominated and spent amount of energy expressed in MWh [22]

Fig. 7. Average price for energy on a daily basis [22]


Маш. инж. науч. спис., 37 (1–2), 5–15 (2019)

6. CONCLUSION

With the implementation of the EnMS the

company's competitiveness and sustainability on

the market is advanced, new business benefits are

opened, energy performance improves and systema-

tic approach to consumption is introduced. The first

savings can be seen through successfully performed

operational control and investments. The most im-

portant benefit is the financial savings, but also the

reduced emission of carbon gases in the air, thereby

reducing the greenhouse effect that leads to global

climate change. A key path to successful implemen-

tation of EnMS is the believe that a change can be

made with the appropriate team and commitment

from top management and through planning, moni-

toring and verification of the action plans for saving,

which improves the energy performance of industri-

al facilities and opens new opportunities and chal-

lenges for saving.

It is necessary to see EnMS system as an con-

tinuous process, and not as a one-time project,

which when it reaches the maximum savings, it will

cease. Energy management is a cycle where there is

always an opportunity for improvement that is not

always visible, until the current period is compared

to the beginning, in order to notice the inevitable

success.

For the production of a single product, the

price may vary considerably. One influential factor

is the price on the market for a certain hour, then the

nomination, thet is to say the amount of energy

taken from the trader, and from the market. The

most important factor for increasing the savings of

the company is the EnMS energy management

system, which monitors the consumption in real

time and can minimize the negative effects of the

market.

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[1] Corporate Industry Program for Energy Conservation: En-

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Efficiency of Natural Resources Canada, Ottawa, 2003.

[2] ISO 50001:2011: Energy Management Systems: Require-

ments with Guidance for Use, Bureau of Indian Standards,

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[3] Foundation for Community Association Research: Energy

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[4] Doty, W., Turner, C., Lilburn, S.: Energy Management

Handbook, 6th edition, The Fairmont Press Inc., 2007.

[5] http://www.esightenergy.com/uk/ – access on 15.01.2017.

[6] ISO 50004:2014: Energy Management Systems, Guidance

for the Implementation, Maintenance and Improvement of

an Energy Management System, Institute for Standardiza-

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[7] ESMAP: Improving Energy Efficiency in Buildings, 2014.

[8] ETSU: Introducing Information Systems for Energy Man-

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management-technology/index.html – access on 20. 02.

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[14] Закон за енергетика, Службен весник на Република

Македонија, бр. 16, 2011.

[15] Мрежни правила за пренос на електрична енергија,

МЕПСО, Скопје, 2006.

[16] Правила за пазар на електрична енергија, Службен

весник на Република Македонија бр. 16, 2011.

[17] Правила за снабдување со електрична енергија, Служ-

бен весник на Република Македонија, бр. 144, 2012.

[18] Правила за пазар на природен гас, Службен весник на

Република Македонија, бр. 16, 2011.

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ник на Република Македонија бр. 16, 2011.

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Microgrids management, IEEE Power Energy Mag., vol.

6, no. 3, pp. 54–65 (May/Jun. 2008).

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кодиноска, К.: Систем за следење и менаџирање со

електичната енергија и останатите енергенси при АД

Макстил Скопје, ЗЕМАК, 2014.

[22] Димовски, К.: Придонес на системот за енергетска

ефикасност во менаџмент на развој на животен цик-

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факултет, Скопје, Јуни 2018.

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Mechanical Engineering – Scientific Journal, Vol. 37, No. 1–2, pp. 17–27 (2019)



Received: May 21, 2019 UDC: 629.43-592:004.942



DEVELOPMENT OF INNOVATIVE BRAKE SYSTEM FOR ROLLING STOCK

Taško Smileski1, Gligorče Vrtanoski2

1MSc Student at the Faculty of Mechanical Engineering, "Ss. Cyril and Methodius" University in Skopje,

Karpoš II bb, P.O. box 464, 1001 Skopje, Republic of N6rth Macedonia 2Faculty of Mechanical Engineering, “:Ss. Cyril and Methodius” University in Skopje,

P.O. Box 464, MK-1001, Skopje, Republic of North Macedonia

[email protected]

A b s t r a c t: In this paper is shown the importance of introducing innovative products in railway industry,

especially when it comes to products from which depends the railway traffic safety, like the brake systems. These brake

systems have the essential function of decelerating and stoping of rolling stock. Because the brake systems are a subject

of large static and dynamic loads in external conditions, the development of this type of system is a long and complex

process. In this paper is shown one part of innovative brake system development by using computer simulation.

Key words: railway; development; brake system; innovation; simulation

РАЗВОЈ НА ИНОВАТИВЕН СОПИРАЧКИ СИСТЕМ ЗА ЖЕЛЕЗНИЧКИ ПРЕВОЗНИ СРЕДСТВA

А п с т р а к т: Во трудот е прикажана важноста на воведување иновативни производи во железничката

индустрија, особено кога се работи за производи од коишто зависи безбедноста во железничкиот сообраќај

како што се сопирачките системи. Овие сопирачки системи имаат есенцијална функција за намалување на

брзината и сопирање на железничките превозни средства. Бидејќи сопирачките системи се изложени на големи

статички и динамички оптоварувања во надворешни услови, развојот на еден ваков систем претставува долг и

сложен процес. Во трудот е прикажан еден сегмент од развојот на иновативен сопирачки систем со користење

компјутерска симулација.

Клучни зборови: железница; развој; сопирачки систем; иновација; симулација

1. INTRODUCTION

Rail transport provides a very important role in

society, not only to enable large number of people

to get to work every day, but also for transport of

materials and goods. The development of rail trans-

port in recent decades goes in direction of increasing

the speed and loading capabilities of rolling stock.

This directly affects the development of brake

technology [5]. The brake system has an essential

function of reducing the speed and braking of

rolling stock for the minimum possible time [3]. The

process of braking is of great importance for the

safety of rail traffic. As railway operators focus on

the need for greater improvements in efficiency and

safety, there is still a considerable need for advan-

cements of railway brake systems [2, 6]. Several

types of brake systems are used in the railways.

Most commonly are used compressed air brake

systems, called pneumatic brake systems [1].

The development of new products contributes

to the growth of companies, affects profits and is a

key factor in business planning [8]. Innovations are

key to the survival of companies. The meaning of

the word innovation is introduction of something

new – change, while invention refers to something

that has never been made before [11]. Throughout

the world there is a popular model – from imitation

mailto:[email protected]

18 T. Smileski, G. Vrtanoski

Mech. Eng. Sci. J., 37 (1–2), 17–27 (2019)

to innovation, and then generating an invention

[12]. Research has shown that investment in product

development is relatively inexpensive and free from

high risk but can lead to a major competitive ad-

vantage in terms of cost savings, customer engage-

ment and increased profits in a company [4].

In the process of developing a brake system,

the most important segment is to use the most ad-

vanced softwares, methods and techniques. The si-

mulation of multi-body dynamics, together with

finite-element simulation, is one of the key methods

for design, homologation and research in the field

of railway and similar vehicles [7]. The optimal

combination of simulation tools, field trials and tes-

ting equipment can be the right way to accelerate the

introduction of innovative technologies, reduce

costs and increase safety, performance and econo-

mic competitiveness in rail transport [14]. Multi-

body dynamic simulation can replace very expen-

sive tests and measurements of the railway vehicle.

Nowadays almost every newly developed railway

vehicle has undergone a multi-body simulation. The

obtained results from the simulation will indicate

whether the brake system meets the UIC standard

criteria for the rail and whether it meets the requi-

rements of the cutomers.

2. MODEL OF BRAKE SYSTEM

2.1. Types of brake systems

From a technical point of view, there are two

main groups of brakes for rail vehicles: adhesion

and non-adhesion brakes (Figure 1).

Fig. 1. Types of brakes for rail vehicles [13]

Adhesion brakes include mechanical brakes

and dynamic brakes. Mechanical brakes are divided

into tread brakes and disc brakes. On disc brakes,

the disc can be axle-mounted or wheel-mounted.

Dynamic brakes include rotating eddy current

brakes, electrodynamic brakes and hydrodynamic

brakes.

Non-adhesion brakes include air resistance

brakes and track brakes. The second type of brakes

includes: magnetic rail brakes and linear eddy cur-

rent brakes.

Brake systems for rail vehicles can also be

classified according to the activation method in the

following categories [3]:

• pneumatic brakes.

• electrodynamic brakes.

• mechanical brakes.

• electromagnetic brakes.

Pneumatic brakes can be classified into two

types:

• vacuum brakes.

• compressed air brakes.

Development of innovative brake system for rolling stock 19

Маш. инж. науч. спис., 37 (1–2), 17–27 (2019)

From all these braking systems, the focus in

this paper is placed on pneumatic tread brake sys-

tems with compressed air.

2.2. Description of conventional brake system

for freight wagons

The conventional brake system for freight

wagons (excluding pneumatic components) consists

of these main components: brake cylinder, slack ad-

juster, pull rods, brake riggings, brake shoe holders

and brake shoes. The schematic view of this brake

system is shown in Figure 2.

The function of the brake system is achieved

by applying pressure in the brake cylinder (1) from

which the generated force is transfered through

brake riggings (3) and slack adjuster (2) onto the

brake shoe holders (4). From the brake shoe holders,

the brake force is transferred on the brake shoes (5)

and onto the wheels of the wagon. The slack ad-

juster (2) has a function to compensate for the wear

of the brake shoes (5) and wheels. When the brake

shoes or wheels are wearing, the brake cylinder has

larger stroke than nominal and it is activating the

trigger (6) of the slack adjuster which decreases the

lenght of the slack adjuster and compensates the

wearing. The gap between the shoes and wheels can

be adjusted by changing the length of the trigger (6).

The simple design of the conventional brake

system is the reason why this system is dominant in

the rail freight market worldwide until the introduc-

tion of integrated bogie brake systems.

Fig. 2. Shematic view of conventional brake system [6]

2.3. Model of innovative brake system

As railway operators focus on the need for

greater improvements in efficiency and safety, there

is a significant need for improvements of the brake

systems [2, 6]. Advanced brake systems lead to

many benefits like improvements in the load

capacity, increasing the safety and optimized life

cycle costs.

The proposed model of the innovative brake

system IBB10 is intended for use in freight wagons

and has the lowest weight on the market. It consists

of a brake cylinder which through a system of levers

and slack adjusters, transfers the force on the brake

shoe holders and onto the brake shoes that come in

frictional contact with the wheels of the wagon. The

brake force is achieved through the brake cylinder

and multiplied through the levers. Two slack adjust-

ers serve to compensate the wear of the brake shoes

and wheels. This brake system design allows easy

assembly and disassembly on each subassembly

separately, which is a great advantage in mainte-

nance and repair of the system. The innovative

IBB10 brake system can be fitted between the

wheels of a bogie type Y25 or similar and it fits the

standard built-in measures as the conventional

brake system. The function of the innovative brake

system is to provide approximately equal brake

force on all four wheels at the same time. The design

is characterized by the use of a brake cylinder with

(or without) a hand brake and two slack adjusters

for automatical adjustment of the gap between the

wheels and brake shoes.

In Figure 3 is shown the innovative system

IBB10 without hand brake. This model of the

innovative IBB10 system is the base for all other

variants.


Mech. Eng. Sci. J., 37 (1–2), 17–27 (2019)

Fig. 3. Model of innovative brake system IBB10 without hand brake [6]

The service brake force is calculated according

to the following equation (1):

F = (p·S·10 – FB)·i·η – FS (N) (1)

where:

– brake cylinder pressure (bar);

– effective piston area (cm2);

– return spring force (N);

– lever ratio;

– efficiency;

– slack adjuster counterforce (N).

From all the listed factors that influence the

service brake force, only the brake cylinder pressure

is a variable, while all other factors are constant.

Taking into account the fact that for different types

of freight wagons a different brake force is needed

and the pressure is defined according to the UIC

standard, from design point of view the ratio of the

levers can be changed.

The innovative brake system IBB10 is in-

stalled on one bogie, and since one freight wagon

usually has two bogies, in most cases, two IBB10

systems will be installed per wagon as a set. Be-

cause each freight wagon should have parking op-

tion when is removed from the train composition (or

because some other reasons), at least one IBB10

unit must have a parking hand brake. In Figure 4 is

shown a variant of the innovative brake system

IBB10 with a platform hand brake. This brake

system with platform hand brake has the same

function as IBB10 without hand brake, but with

added function of the hand application of a parking

brake. The application of the platform hand brake is

done from the platform of the wagon.

Fig. 4. Model of innovative brake system IBB10 with platform hand brake [6]

p

S

BF

i

SF

p

i


Маш. инж. науч. спис., 37 (1–2), 17–27 (2019)

The activation of the platform hand brake

should be performed from the platform of the freight

wagon by turning the hand wheel through a box

with conical gears and a telescope cardan shaft,

which is connected with the spindle of the platform

hand brake mechanism. In Figure 5 is shown a

model of Y25 bogie with installed brake system

IBB10 with platform hand brake and connecting

components for activation with segment of the

wagon platform. By turning the hand wheel, the

torque is transmitted through the gears and the

cardan shaft to the spindle of the platform hand

brake mechanism activates (extends) the brake

cylinder. This mechanism is connected to the piston

rod and during service brake it moves together with

the piston rod. The connection of the hand brake to

the platform is necessary to be performed with a

telescope cardan shaft in order not to decrease the

degrees of freedom of the brake system during

braking and releasing.

Fig. 5. Model of Y25 bogie with installed brake system IBB10 with platform hand brake and connection components

for activation with segment of the wagon platform

3. MULTI-BODY SIMULATION OF THE

INNOVATIVE BRAKE SYSTEM

In the multi-body simulation is used finite ele-

ment method, which is a key method for design, ho-

mologation and research in the field of railways and

railway vehicles [7]. This type of simulation is one

of the most advanced methods for developing and

optimizing a designed mechanism. Because the

brake system is a subject of large static and dynamic

loads during the braking process, it is necessary that

the brake system has undergone multi-body simula-

tion before the prototype is produced. Figure 6

shows a 3D model of the innovative brake system

IBB10 with platform hand brake for multi-body

simulation.

The main components of the innovative brake

system IBB10 with platform hand brake, which are

shown in Figure 6 and are evaluated in the simula-

tion are the following:

1. Four hangers on which the brake system are

supported.

2. Special rubber bushings mounted on the han-

gers to provide freedom of movement and

reduce vibration.

3. Brake shoes that in the 3D model are shown

with an approximate geometry.

4. Primary beam which is one of the most loaded

elements in the system.

5. Secondary beam which due to the slack adjust-

ers location is not subject to high loads.

6. Two slack adjusters that in the 3D model are

presented as rigid bodies with a weight corres-

ponding to the real one. Given the complexity

of the slack adjusters that would greatly comp-


Mech. Eng. Sci. J., 37 (1–2), 17–27 (2019)

licate the simulation, the internal components

will not be analyzed.

7. Brake cylinder which is connected with four

levers to the primary beam.

8. Four levers which perform multiplication of the

force from the brake cylinder to the slack ad-

justters. In addition to the loads in the horizon-

tal direction, under the action of vertical vibra-

tions, they are heavily loaded in the vertical

direction.

9. Platform hand brake which due to the large

number of levers and connection elements will

be represented as a rigid body with a weight

equal to the real one.

Fig. 6. 3D model of IBB10 with platform hand brake for simulation [10]

Considering that the brake system is in direct

relation with the bogie of the wagon, it is necessary

to include in the simulation all main elements that

are in direct relation to the brake system and the rail.

The accelerations to be included in the simula-

tion are according to BS EN 13749 [9]. This stand-

ard defines the accelerations in each direction which

are used in the calculation and are divided into two

classes. For components related to the bogie are

considered the acceleration values in Table 1, while

the components related to the wheelset are the ac-

celeration values listed in Table 2. It is obvious that

the accelerations of the wheelset related compo-

nents are greater (especially in the vertical direc-

tion) because the wheels are the most exposed com-

ponents of the entire wagon and are directly affected

by all irregularities of the rail. All components con-

nected to the bogie are subject to minor accelera-

tions because there are suspension springs between

the body of the bogie and the axles of the wheels.

As the brake system is connected to the bogie,

the accelerations shown in Table 1 are most com-

monly used (when the system is released). In case

of braking, due to the frictional contact between the

wheels and the brake shoes, the acceleration of the

wheels is transmitted to the brake system. In this

case there will be combined acceleration values

from Table 1 and Table 2. Also, becuse of the dy-

namic nature of the braking process caused by the

contact of the brake system and the rotating wheels,

there are additional loads which need to be consid-

ered.


Маш. инж. науч. спис., 37 (1–2), 17–27 (2019)

T a b l e 1

Accelerations according to EN 13749 – Table D.1

(bogie mounted parts) [9]

Direction Extreme

acceleration (g)

Continual acting

acceleration (g)

Vertical ±20 ±6

Transversal ±10 ±5

Longitudinal ±5 ±2.5

T a b l e 2

Accelerations according to EN 13749 – Table D.2

(wheelset mounted parts) [9]

Direction Extreme

acceleration (g)

Continual acting

acceleration (g)

Vertical ±70 ±25

Transversal ±10 ±5

Longitudinal ±10 ±5

Figure 7 shows 3D model of Y25 bogie, which

includes the innovative brake system IBB10 with

platform hand brake. This 3D model does not show

the springs between the wheel axles and the body of

the bogie to reduce the complexity of the entire sys-

tem, but during the simulation itself, the functio-

nality of the springs is taken into account.

The dynamic simulation model has a role to

simulate the analyzed system as realistically as

possible. In this case, during the simulation, it is

assumed that the wheels are in contact with the rail

and rotate in the direction shown in Figure 8. In the

middle area where the spherical joint of the bogie is

positioned is added a load in the form of a mass

dummy. This mass dummy simulates the load,

expressed as half of the mass of the entire wagon

(Figure 9).

For a clearer view of the analyzed model, in

Figure 9 is shown in several views, where the main

components of the 3D model are described.

Fig. 7. 3D model of Y25 bogie and IBB10 with platform hand brake for simulation [10]

Fig. 8. Supports and constraints on the 3D model of the bogie and IBB10 for simulation [10]


Mech. Eng. Sci. J., 37 (1–2), 17–27 (2019)

Fig. 9. Description of the 3D model for multi-body simulation [10]

Given that the mass of the wagon is variable,

depending on whether it is empty or loaded, know-

ing the stiffness characteristics of the springs on the

bogie, the position of the entire analyzed system can

be simulated. Figure 10 shows the height of the

IBB10 in relation to the wheel axis in the case of

empty wagon (m = 26 t) and in fully loaded wagon

(m = 90 t). In fully loaded static position the height

of the bogie is 30 mm lower compared to the empty

wagon. Because in the analysis is included only one

bogie, while the wagon has two, the weights that

will act on one bogie will be two times smaller than

the indicated ones.

Fig. 10. Height of the bogie relative to the wheel axis on empty wagon (left) and fully loaded wagon (right) [10]

Taking the above parameters, in order to verify

the connection of the elements in the 3D model, it is

necessary to make an initial simulation. Figure 11

shows the force on the hangers (position 1 in Figure

6) due to gravity load. The results of this initial

simulation show a good correspondence with the

analytical calculation.

It should be noted that there is a different load

force on the hangers because there is unequal

distribution of the masses due to the location of the


Маш. инж. науч. спис., 37 (1–2), 17–27 (2019)

brake cylinder (and the hand brake). The H1 and H2

hangers which are located near the primary beam

are more loaded (in a static position with force F ≈

750 N), while the hangers located near the second-

ary beam H3 and H4 are less loaded (in a static

position F ≈ 250 N). The goal of correctly setting

the initial conditions is to get as much accurate

results as possible. The results of such analysis are

obtaining the stresses and deformations in the

analyzed cases. More important is the get the maxi-

mum stresses in the analyzed cases, but in some

cases when the system needs to have a smaller or

larger elasticity, deformations play more important

role.

Fig. 11. Hanger force due to gravity load [10]

Figure 12 shows deformations of the levers

which are connecting the brake cylinder to the

primary beam and the slack adjusters. As can be

seen, the maximum deformation is ≈ 3.7 mm and

it occurs in the case of extreme vertical vibrations.

The design of this brake system limits these

deformations due to cylinder holder which is in a

sliding connection with an U-profile which is

mounted on the primary beam. This holder limits

the movement and deformation of the levers in a

vertical direction. This is shown in Figure 13.

Obtaining the maximum stresses from the load

cases is of great importance in order to create

optimized design and to make maximum utilization

of the material. In this way lighter and cheaper

products can be designed, which is a very noticeable

trend nowadays. Figure 14 shows the stresses of the

levers in extreme load case

Fig. 12. Lever - deformation in extreme load case [10]


Mech. Eng. Sci. J., 37 (1–2), 17–27 (2019)

Fig. 13. Brake cylinder holder limits the deformation of the levers [10]

Fig. 14. Lever – stresses during extreme load case [10]

CONCLUSION

This paper shows one part of the development

of a complex mechanical system – an innovative

brake system for rolling stock. Considering that the

brake systems are of great importance for the safety

of rail traffic and are exposed to large static and

dynamic loads under external conditions, the

development of such system is a long and complex

process.

In the process of developing a brake system,

the most important asset is to use the most advanced

softwares, methods and techniques. Multi-body

simulation together with finite element analysis is

one of the key methods for design, homologation

and research in the field of railways and railway

vehicles. Multi-body simulation can replace very

expensive tests and measurements of the railway

vehicle. Nowadays almost every newly developed

product for the railway industry goes through multi-


Маш. инж. науч. спис., 37 (1–2), 17–27 (2019)

body simulation. The results of the simulation

indicate that the brake system satisfies the UIC

standard criteria and meets the requirements of the

customers. By successfully passing the simulation,

there is a significant increase of the chances for

successfully completing the validation tests and

successfully palcing this innovative brake system

on the market.

REFERENCES

[1] Chary, R., Khan, E.: Design and Analysis of Train Brake

System, International Journal of Advanced Research and

Innovation, Vol. 7, Issue 3, pp. 27–33 (October 2014).

[2] Wynd, D., Connelly, M.: Advanced Bogie Brakes, Proce-

edings, Conference on Railway Engineering, Wellington,

September 12–15, 2010.

[3] Sharma, R. C., Dhingra, M., Pathak, R. K.: Braking Sys-

tems in Railway Vehicles, International Journal of Engi-

neering Research & Technology, Vol. 4, Issue 1, pp. 204–

211 (January 2015).

[4] Дуковски, В.: Менаџмент на развојот на нови произ-

води, Универзитет „Св. Кирил и Методиј“, Скопје,

2001.

[5] Smileski, S., Smileski, T.: Integrated bogie brake and

slack adjuster for the use with said integrated bogie brake,

Patent WO 2013098350 A2, December 27, 2011.

[6] Smileski, T., Rakipovski, R., Mičić, M.: Comparison of

Classical Brake for Freight Wagons with New Integrated

Bogie Brake IBB10 for Freight Wagons, RAILKON `16,

Niš, October 13–14, 2016.

[7] Weidemann, C.: State of the Art Railway Vehicle Design

with Multi-Body Simulation, Journal of Mechanical

Systems for Transportation and Logistics, Vol. 3, No 1, pp.

12–26 (2010).

[8] Bhuiyan, N.: A framework for successful new product de-

velopment, Journal of Industrial Engineering and Mana-

gement (JIEM), Volume 4, Issue 4, pp. 746–770 (2011).

[9] BS EN 13749:2011, Railway Applications – Wheelsets and

Bogies. Method of specifying the structural requirements

of bogie frames, 2011.

[10] Artner, W.: MBD/FEA-Analysis IBB10 Brake System New

Design, Report a 13010 RV0, November 2013.

[11] Вртаноски, Г.: Иновациите и инвенцијата – vслов за

излез од економската криза, предавања на постдип-

ломски студии (ПЛМ), Развој и менаџмент на произ-

водите, Универзитет „Св. Кирил и Методиј“, Машин-

ски факултет, Скопје, 2012.

[12] Kim, L.: Imitation to Innovation – The Dynamics of Ko-

rea's Technological Learning, Harvard Business School

Press, 1997.

[13] Lunden, R., Vernersson, T.: Mechanical braking systems –

development and challenges, Presentation at 19th Nordic

Seminar on Railway Technology, Chalmers University of

Technology, Lulea, September 14–15, 2016.

[14] Pugi, L., Palazzolo, A., Presciani, P., Fioravanti, D.: Simu-

lation and optimization of railway pneumatic braking sys-

tem, World Congress for Railway Research WCRR2006,

Montreal, June 2006.




Received: May 21, 2019 UDC: 005.61-049.3:621.98-034.1

Accepted: August 21, 2019


TOTAL PRODUCTIVE MAINTENANCE – TOOL TO IMPROVE

THE COMPANIES PERFORMANCE

Andon Naskovski1, Gligorče Vrtanoski2

1MSc Student at the Faculty of Mechanical Engineering, “Ss. Cyril and Methodius” University in Skopje,

P.O. box 464, MK-1001, Skopje, Republic of North Macedonia 2Faculty of Mechanical Engineering, “Ss. Cyril and Methodius” University in Skopje,

P.O. box 464, MK-1001, Skopje, Republic of North Macedonia

[email protected]

A b s t r a c t: The research of the paper shows the implementation of TPМ methodology on total maintenance

and its main tool, Autonomous Maintenance (AM). The goal is to increase the productivity and efficiency of an existing

production line for pickling metal sheet. Total analysis of the production line is done by identifying weak points, i.e.

assemblies using the Overall Equipment Effectiveness (OЕE) indicator. With applying the main tool, autonomous

maintenance from TPM methodology, an attempt has been made to identify the anomalies, a system for reporting errors

has been created, the number of standards and education of the operators has increased, and in order to reduce the

number of delays in the production line. This will improve the efficiency of the employees and the productivity of the

company as a whole.

Key words: maintenance; total productive maintenance – TPM; preventive maintenance; autonomous maintenance;

overall equipment effectiveness

ЦЕЛОСНО ПРОДУКТИВНО ОДРЖУВАЊЕ – АЛАТКА ЗА ПОДОБРУВАЊЕ

НА ПЕРФОРМАНСИТЕ НА КОМПАНИИТЕ

А п с т р а к т: Истражувањето претставено во трудот ја прикажува имплементацијата на методологијата

на целосно продуктивно одржување (ТРМ), како и нејзината главна алатка – автономно одржување (АM).

Целта е зголемување на продуктивноста и ефикасноста на постојна производствена линија за лужење на чели-

чен лим. Целосното анализирање на производствената линија е направено преку утврдување на слабите точки,

т.е. склопови со помош на индикаторот за севкупна ефективност (ОЕЕ).. Со имплементацијата на главната

алатка – автономно одржување (АM) на методологијата ТРМ, направен е обид да се идентифкуваат аномалии-

те, креиран е систем за информирање за грешки, зголемен е бројот на стандарди и едукации на операторите, а

со цел да се намали бројот на застои на производствената линија. Со тоа ќе се подобри ефикасноста на врабо-

тените и продуктивноста на компанијата во целост.

Клучни зборови: oдржување; целосно продуктивно одржување – ТРМ; превентивно одржување;

автономно одржување; севкупна ефективност на опремата

1. INTRODUCTION

In today’s dynamic environment, the reliabil-

ity of the systems is crucial to creativity. The poor

organizational competence in the management of

the maintenance functions may have a serious im-

pact on the competitiveness by reducing the pro-

gress, increasing the supply and not meeting the

deadlines. The equipment, technology and develop-

ment of its features become a substantial factor that

demonstrates the power of the organization and in

that manner separates it from the other companies.

The maintenance is becoming a strategic tool, un-

like before, when the only objective of surveillance

was the maintenance cost decrease. The investment

in the maintenance is one of the basic functions of

the company. It reflects in the quality improvement,

the safety, the flexibility and production time. Over


30 A. Naskovski, G. Vrtanoski

Mech. Eng. Sci. J., 37 (1–2), 29–40 (2019)

the last decade, the opinion that the maintenance is

not a separate, isolated function and it needs to be

treated as all the other company activities have be-

come predominant. Maintenance is a full partner of

the rest of the organizational functions and should

strive to realize the company’s strategic goals. The-

refore, maintenance is becoming a strategic neces-

sity for the manufacturers worldwide. Increase of

business pressure put the maintenance as a key role

in the company’s functions. The modern manufac-

turing requires that the organization, if it wants to

achieve have a World Class Manufacturing – WCM,

has both features – effective and efficient mainte-

nance.

As part of the benchmark ideas for organiza-

tional performances and processes improvement,

regarding the competition, the TPM has been identi-

fied as the best solution to increase the company

productivity.

2. OVERVIEW OF THE LITERATURE

RESEARCH

The researcher R. Kennedy [5] actualizes total

productive maintenance (TPM) in the manufactur-

ing as a revolutionary approach in the maintenance.

The main point of the TPM is that it develops out-

side the lean approach. Its significance goes far bey-

ond the limited view of maintenance because it is a

part of a total approach to more productive manu-

facturing. The TPM concept addresses the maxi-

mization of overall plant and equipment effecttive-

ness through the elimination or minimization of the

six machine losses, creating a sense of ownership

for plant and equipment operators through a process

consisting of training, involvement and promoting

continuous improvement through small group acti-

vities involving production, engineering and mate-

rial personnel.

There are several researches carried out by dif-

ferent researchers that review and determine the sig-

nificance of the development and application of the

TPM in the production [3, 7, 8]. It is well known

that TPM is introduced in the company, if the appli-

cation is done when many employees participate.

All involved participants need to be focused and

need to cooperate at all levels. Team work is the

most important factor. There are many approaches

in the application of the TPM, but there is no evi-

dence for non-application due to a certain problem.

The total productive maintenance (TPM) is an

improvement in the manufacturing, i.e. it is a practi-

cal analogy to the total quality maintenance (TQM),

while the Japanese researchers explain it as concept

for management with the equipment in order to

achieve increased productivity by involving all em-

ployees. According the researcher S. Nakajima [3],

TPM’s objective is to continuously improve the

equipment and prevent equipment deterioration, in

order to achieve maximum efficiency. These ob-

jectives require strong management and great sup-

port from all involved employees.

TPM may be analyzed in three words [3]:

• Total: Meaning involvement from workers to

top management employees.

• Productive: Meaning no more unnecessary ac-

tivities or manufacturing delay and focusing

on services that satisfy the consumers’ needs.

• Maintenance: Keeping the equipment and

company clean and in an operating condition

that is good or even better than the original.

The success of every business improvement is

a strategy that rests on a strong and dynamic leader-

ship that has to be presented by winners. The author

J. Levitt [6] in his work points out that the key play-

ers for the TPM are the machine operators. In this

case the maintenance staff has an advisory role.

Also, he states that the winning factor of the TPM is

to train the operators to an extent that would be suf-

ficient to achieve full AM.

The earliest application of the TPM is in Japan,

especially in the fast-growing automobile industry,

i.e. in the Toyota Company and its branches. As a

result, many Japanese companies, encouraged by

the Toyota’s success, started to apply the TPM, but

at the early beginning there was no noticeable suc-

cess [9]. All of this changed in 1970 when Japan

faced economy decrease. From that moment it star-

ted to rapidly adapt TPM in order to improve the

manufacturing productivity [10]. The TPM applica-

tion process has been developed by the researcher

S. Nakajima [3]. He developed the process in sev-

eral stages in order to provide standardized and re-

peatable methodology.

For comparison, there are two different ap-

proaches to define the TPM: the Japanese approach

presented by the authors S. Nakajima [3], F. Gotoh

[9] and K. Shirose [11], and the Western approach

by the authors P. Willmott [12] and T. Wireman

[13]. These two approaches are also supplemented

by the approach of the author C. Bamber [14]. The

differences between the Japanese and the Western

approaches defining the TPM are small compared to

the similarities that are much more significant. The

Japanese value the team work in small groups and

participation of all company employees in the TPM

Total productive maintenance – tool to improve the companies performance 31

Маш. инж. науч. спис., 37 (1–2). 29–40 (2019)

process application, in order to meet the improve-

ments intended for the equipment used. The West-

ern approach is more focused on the equipment,

while the employees’ involvement in the goal achie-

vement is not crucial. Although it can be noticed

that both approaches are very similar, the Japanese

approach focuses on the people and the process,

while the Western approach starts from the im-

provement of the equipment efficiency, which does

not separate it from the team work, but also does not

lead to correct equipment management and equip-

ment use [14].

3. TOTAL PRODUCTIVE MAINTENANCE

(TPM)

TPM is an innovative Japanese concept. The

origin of TPM can be traced back to 1951 when pre-

ventive maintenance was introduced in Japan. How-

ever, the concept of preventive maintenance was

taken from USA. Nippondenso was the first com-

pany to introduce plant wide preventive mainte-

nance in 1960. Preventive maintenance is the con-

cept wherein operators produced goods using ma-

chines and the maintenance group was dedicated

with work of maintaining those machines, however

with the automation of Nippondenso, maintenance

became a problem, as more maintenance personnels

were required. So the management decided that the

operators would carry out the routine maintenance

of equipment [1].

TPM is a complex and long process that shows

the employees that it is a legitimate methodology

which would improve the processes. If the TPM is

to be successful in any industry, both teams – the

management and workers, must operate in an at-

mosphere that would be beneficial to the company.

The company employees need to truly take action if

this methodology is to succeed.

TPM is consisted of eight pillars. Its method-

ology has a manner of excellent planning, organiza-

tion, monitoring and practical control applied

through the eight pillars. The TPM initiative, as pro-

moted by the Japanese Institute for Plant Mainte-

nance, includes a plan for application of all eight

pillars that need to make gradual improvement of

the productivity through controlled maintenance,

reduction of costs and decreased delays. The meth-

odology core (Figure1) is classified in eight pillars

and activities:

• 5S

• Autonomous maintenance (AM).

• Focused maintenance.

• Planned maintenance.

• Quality maintenance.

• Education and training.

• Office TPM.

• Safety, health and environment protection.

Fig. 1. The pillars of TPM [10]

The mission of each pillar is to reduce losses

in order to eliminate all losses in the process.

Prior to the initiation of the TPM application it

is necessary for the management to compose a pro-

gram and inform all employees so that they could

understand that it is a matter of long-term program

that change the company culture, and not just an in-

itiative intended for the maintenance services.

TPM structure supports the culture changes

where the responsibilities and ownership of the pro-

cesses are clearly defined and supported.

We may also mention that the pillars within

themselves change the direction, develop the sys-

tem, process and standards along with the employ-

ees. It enables and motivates the leaders to operate

with their employees and teams to decrease the bar-

riers between them in order to create a single and

cohesive system where all employees from all levels

would work to achieve the same goal. This is a man-

ner of change management and observance of a

strict methodology which would provide consistent

future results. The manner of establishing of this

methodology is the application of all eight pillars.

By applying TPM many companies mark productiv-

ity increase as well as increase of the reliability of

the machines, the malfunction frequency is de-

creased and the effectiveness of the quality is in-

creased. However, it mostly affects the increase of

the productivity. This proactive strategy may con-

tribute to the improvement of the performances

stressed in many researches.


Mech. Eng. Sci. J., 37 (1–2), 29–40 (2019)

4. TECHNICAL DESCRIPTION

OF PRODUCTION EQUIPMENT

The application of one of the TPM tools, i.e.

the AM, and the need of its application will be

displayed in this chapter. The production line for

pickling metal sheet is integral part of the company

Arcelor Mittal – Skopje. The equipment is com-

posed of several assembly parts and it works as one

entirety. During its operation there are often delays

that are predictable due to certain events, but some

of them cannot be predicted as they occur suddenly.

The production pickling metal sheet line is shown

on Figure 2 and is made by the British company

WEAN LIMITED INC. The production line is for

producing the pickled metal sheets in a form of

strips, made from the hot rolled materials according

to the standards used for cold forming of sheet.

Fig. 2. Production process of pickled metal sheet [2]

4.1. Overview of delays and problems within

the period 2014–2017

The use of all tools offered by the AM defines

the critical equipment of the pickling metal sheet

line. The annual reports on the delays, as well as the

total line effectiveness are the biggest indication on

the major problems. The five most critical pickling

metal sheet assemblies are determined through

these reports for the period from 2014 to 2017, as

well as the analysis of the total effectiveness, but

they also determine the year of worst delays. The

chart shown on Figure 3 displays the delays in a

time interval on the pickling metal sheet assemblies

for the period from 2014 to 2017.

Fig. 3. Duration of delays of the assembly from 2014 to 2017 [2]


Маш. инж. науч. спис., 37 (1–2). 29–40 (2019)

The Figure 4 is a graphical display of the total

delay period of the pickling metal sheet line assem-

blies, for each year separately for the period from

2014 to 2017. Based on that, it has been determined

that the worst year with the biggest number of de-

lays on the pickling metal sheet line is 2014. This

year is taken as a reference for the determination of

the overall equipment effectiveness (ОЕЕ).

Fig. 4. Total pickling metal sheet delay period by years

5. DEFINITION OF OVERALL EQUIPMENT

EFFECTIVENESS INDICATOR

The overall equipment effectiveness (OEE) is

a key indicator for the performances of a process or

equipment. It may be set as a benchmark for the

measuring or analysis of a process and its effective-

ness. In other words, the OEE is the full use of time,

materials and facilities during the production pro-

cess [4]. The ОЕЕ is calculated based on the follow-

ing three indicators:

1. Availability (R) – is the ratio of actual produc-

tion time that a machine is working divided by

the time the machine is available.

2. Performances (P) – is the percentage of total

number of parts on that machine to its produc-

tion rate. In simple words, performance mea-

sures the ratio of actual operating speed of the

equipment and the ideal speed.

3. Quality (Q) – is an indicator calculated as the

proportion of the total number of functional

products manufactured with the machine and

the total number of products manufactured

within a period of one year production.

After the three indicators are defined, the OEE

can be calculated with the equation (1):

OEE = R·P·Q (1)

The calculated values of the OEE with the

equation (1) are values between 0 and 1 or expres-

sed in percentage it would be between 0% and

100%. The Table 1 displays the ideal values of the

three indicators, as well as the value of the ОЕЕ

after the application of the recommendations for

World Class Manufacturing [3, 4]. It is recommen-

ded and acceptable for the OEE to be 60% in which

case the companies achieve satisfactory results [4].

The Table 1 displays the calculated indicators

and the ОЕЕ for each individual year within the re-

viewed period. According to the data in the Table 1,

it is visible that 2014 has the worst effectiveness.

The reason due to which 2014 has this result is the

system of operation that existed that year, i.e. the

small-scale production planned. The occurrence of

a large number of delays of the pickling metal sheet

line contributed to this outcome. This shows that the

pickling metal sheet line in 2014 was at a delay for

one fifth of the available time and did not manu-

facture.

T a b l e 1

Ideal and calculated indicators

of the overall equipment effectiveness [3] (%)

Year R

Availability

P

Performances

Q

Quality

ОЕЕ – total

efectiveness

2014 82 64 92 48

2015 86 63 91 49

2016 80 71 94 53

2017 84 72 95 57

Ideal

values 90 95 99 84,645

5.1. Determine of critical equipment

Following the instructions from the research

[2], the most critical year within the period from

2014 to 2017 needs to be determined and then also

the five most critical assemblies for that year. Figure

3 displays the duration of the delays of the pickling

metal sheet line for the period from 2014 to 2017,

with 2014 being the most critical one. It also dis-

plays the ОЕЕ of the equipment for the period from

2014 to 2017 with the results given in Table 1, con-

firming that 2014 is a critical year when the equip-

ment is less effective. Analyzing the aforementi-

oned, it shall be considered that 2014 defines the

five critical pickling metal sheet line most critical

assemblies.

The critical assemblies of the pickling metal

sheet line are determined using the recommenda-

tions [2]. The Table 2 displays the ranked critical

assemblies based on special marks indicators for


Mech. Eng. Sci. J., 37 (1–2), 29–40 (2019)

several parameters such as: delays, quality, manu-

facturing, safety, maintenance costs, average time

for repair etc. By expressing the real evaluation of

the assemblies in Table 2, the classification of the

assemblies can be made. In this manner the assemb-

ly with over 15 points are set in the “AA” class, of

the most critical assemblies, the assemblies with 10

to 15 points are set in the “A” class, or critical as-

semblies, the assemblies with 1 to 9 points are set in

the “B” class, or problematic assemblies, and with 0

points are set in the “C” class, or defect free assem-

blies. The evaluation of the steel sheet metal pick-

ling line assemblies is made in the presence of ex-

perts from the maintenance and production sectors.

T a b l e 2

Pickling metal sheet line equipment ranking

Assembly MTTR

(min)

Number

of delay

Quality

impact

Production

impact

Safety

impact

Maintenance

costs

Total

points Class

1 Entry conveior 0 0 0 5 5 5 15 AA

Entry coil opener 0 0 0 2 1 1 4 B

2 Uncoiler 84 5 5 5 5 5 20 AA

3 Entry transfer car 300 6 5 5 5 5 20 AA

Entry hydraulic 250 4 3 5 1 5 14 A

4 Processor 112 7 5 5 1 5 16 AA

6 Mechanical shear 0 0 5 0 0 1 6 B

5 Welding machine 40 3 5 5 5 5 20 AA

7 Entry bridle rolls 360 2 5 5 0 3 18 AA

8 Entry Looper 0 0 1 1 1 2 5 B

Baths 0 0 1 1 1 1 4 B

12 Exit roll after baths 30 1 4 3 1 5 13 A

14 Side trimming machine 45 2 5 5 5 5 20 AA

Crop shear 0 0 1 1 1 1 4 B

Rubber conveior for mettal waste 0 0 1 1 1 1 4 B

15 Exit bridle rolls 540 1 5 5 1 2 13 A

System for oiling of strip 0 0 0 0 0 0 0 C

Coiler 0 0 5 5 1 3 14 A

Exit hydraulic 0 0 5 5 1 5 16 AA

16 Coil oppener 0 0 0 0 0 0 0 C

18 Fan 0 0 0 5 5 5 15 AA

Other 60 2 3 3 2 3 11 A

6. IMPLEMENTATION OF TPM TOOL:

AUTONOMOUS MAINTENANCE

The calculations that were done show the pro-

duction pickling metal sheet line has to be modified

regarding the manner of operation. By applying the

TPM tool: autonomous maintenance (AM), the de-

crease of the number of delays will be affected, as

well as the productivity increase. The application of

the AM will be based on the five critical points.

Also, the application of the AM is intended to elim-

inate the several adverse aspects occurring in the

course of operation such as:

• High costs due to excessive number of delays.

• Contaminated and damaged equipment.

• Important quality losses.


Маш. инж. науч. спис., 37 (1–2). 29–40 (2019)

• Limited knowledge of the equipment by the

operators.

• Very small number of improvement proposi-

tions.

By applying the AM, which is a part of the

TPM methodology, many good results may be achi-

eved regarding the improvement of the productivity

and decrease of the number of delays. This is confir-

med by using a line of indicators appearing during

the application of the seven steps of the AM. While

applying the first step, cleaning, an equipment ano-

maly notification system has been introduced. The

system is composed of two notification manners

with blue labels intended for the solution of the

problems by the AM-teams and red labels intended

for more serious problems solved by the maintenan-

ce teams.

Fig. 5. Expected blue label results

Figure 5 displays the expected results of the

blue labels after the application of the first step of

the AM. The blue labels mark which of the AM-

team members can solve the problems without

company maintenance assistance. By analyzing the

receive results displayed on Figure 5 it can be

expected that the number of found anomalies and

solved anomalies will grow each year. The solved

blue labels intended for the AM-teams shall mark

the defects solved by the AM-teams.

Fig. 6. Expected red label results

The Figure 6 displays the red label results after

the application of the first step of the AM. The ano-

malies marked with red labels are intended for the

company maintenance members, i.e. those are ano-

malies which the AM-teams cannot solve them-

selves. Analyzing the results displayed on Figure 6,

it can be expected that an increase will take place

regarding the solved and detected anomalies mar-

ked with red labels each year. After the application

of the first step of the AM, it is expected that the

AM-teams’ members will be trained for correct use

of the notification system.

While applying the second step of the AM an

inspection has been made of the most critical points

of the steel sheet metal pickling line, whereby the

anomalies detected are divided in several categories

and are displayed on Figure 7. After the application

of this step, the operators will be one level higher in

732

1427

2163 2167

701

1427

2099 2112

0

500

1000

1500

2000

2500

2018 2019 2020 2021

Nu

mb

er

of

an

om

ali

es

Time (years)

found anomalies marked withblue labels

solved anomalies marked withblue labels

274

559

886 881

235

444

786 790

0

200

400

600

800

1000

2018 2019 2020 2021

Nu

mb

er

of

an

om

ali

es

Time (years)

found anomalies markedwith red labelssolved anomalies markedwith red labels


Mech. Eng. Sci. J., 37 (1–2), 29–40 (2019)

the familiarization with the equipment and its func-

tioning. In that manner, they are no longer passive

observers, but become active participants in the

problem prevention.

The Figure 7 displays the critical equipment

anomalies prior to the application of the AM. Ana-

lyzing the results, it can be noticed that there are too

many anomalies of the critical equipment. The ano-

malies detected refer to all critical points. The

Figure 7 also displays that the category of unneces-

sary openings and damaged protective parts is the

most critical.

After the application of the second step, it may

be expected that all anomaly categories decrease.

This fact is displayed on the Figure 8.

With the application of the third step from the

AM, standardization, intended to create standards

for the critical points, it can be expected that the

number of small delays will decrease. It is due to the

insufficient knowledge of the equipment the opera-

tors have. The development of the standards for the

critical points of the equipment is necessary, as well

as the mutual cooperation with the operators,

includeing the company maintenance.

Fig. 7. Critical equipment anomalies prior to the application of the autonomous maintenance (AM)

Fig. 8. Critical equipment anomalies after to the application of the autonomous maintenance (AM)


Маш. инж. науч. спис., 37 (1–2). 29–40 (2019)

The Figure 9 displays the number of expected

developed standards after the first year of applica-

tion of the AM. Analyzing the obtained results, it

can be observed that rapid progress is expected

within a year from the application of the AM. This

progress is necessary because there are no standards

developed for the pickling metal sheet line up until

the AM commencement, and with that the entire

system is based on the operators’ experience.

The Figure 10 displays the number of devel-

oped standards after the first year of application of

the AM, for each individual critical point of the

equipment.

Fig. 9. Number of standards developed after the first year of the AM application

Fig.10. Number of standards developed after the first year of the AM application

The Figure 10 displays the results from which,

it can be observed that the most of the developed

standards are envisaged for the critical equipment –

welding machine. No standards exist for this equip-

ment and therefore the operators face problems such

as machine settings that sometimes can take up to

two or three hours. After the application of the third

step these problems are expected to be eliminated

and in the same time the operators’ knowledge of

the equipment is expected to increase.

The achieving of the objective to decrease the

number of delays and increase productivity may be

0

15

20

23

2526

2829

3130

35

38

0

5

10

15

20

25

30

35

40

jan feb mar apr may jun jul aug sep oct nov dec

Nu

mb

er

of

sta

nd

ard

s

Time (months)

89

10

56

0

2

4

6

8

10

2.Uncoiler 3.Entry transfercar

5.Weldingmachine

7.Entry bridlerolls

14.Sidetrimmingmachine

Nu

mb

er

of

sta

nd

ard

s

Critical equipment


Mech. Eng. Sci. J., 37 (1–2), 29–40 (2019)

expected to be reached after the application of all

seven steps of the AM. The Figure 11 displays the

increase of the overall epquipment effectiveness

(ОЕЕ) of the equipment after the application of the

AM of an identical production line in the Arce-

lorMittal Company, Gent, Belgium. The displayed

results on the Figure 11 show the OEE increase

trend from the beginning of the application of the

seven steps of AM in 2005, until the final applica-

tion of the AM in 2008.

Analyzing the Figure 11, it can be noticed that

the ОЕЕ of the equipment is satisfactory, staring

from 2005 and finishing in 2008. The achieved

results fully justify the correct decision of the

ArcelorMittal Company, Gent, to apply AM.

The Figure 12 displays the expected results for

the ОЕЕ of the pickling metal sheet line in the

ArcelorMittal – Skopje company. The columns

marked with blue and red color, i.e. the time period

by years from 2014 to 2017, give the actual data

used in the calculation to prove the need of

modification of the AM in the operation manner of

the production line. The columns marked with green

color, i.e. the time period by years from 2018 to

2021, represent the time during which the AM is to

be applied. That is the time period for which there

is no particular data, but due to comparison, the data

given on the Figure 11 for the period from 2005 to

2008 are used, as comparison values in the

application of the AM.

Fig. 11. Overall equipment effectiveness (ОЕЕ) after the application of the autonomous maintenance (AM) [9]

Fig. 12. Envisaging of the overall equipment effectiveness (OEE) for the period from 2014 to 2021

74,83

75,59

70,11

66,42

69,964,74

72,4372,52

58,94

63,61

69,5670,59

75,15

71,4571

77,21

68,96

64,94

79,02

0

10

20

30

40

50

60

70

80

90

Ove

rall

Eq

uip

me

nt

Eff

ec

tive

ne

ss

-ОЕ

Е (

%)

Time (years, months)

48 4953

57

75,59 76 77,5 79,02

0

10

20

30

40

50

60

70

80

90

Basis 2014 2015 2016 2017 2018 2019 2020 2021

Ove

rall

Eq

uip

me

nt

Eff

ec

tive

ne

ss

-ОЕ

E (

%)

Time (years)


Маш. инж. науч. спис., 37 (1–2). 29–40 (2019)

The predictions given in the Figure 12 repre-

sent the results from the ОЕЕ by years during the

application of the AM of the equipment and if in any

part of the four year application the results obtained

differ from the expected, immediate reaction is

needed to detect and solve the problem and correct

the course of events in the application.

The Figure 13 displays the comparative analy-

sis of the application of the AM between the expec-

ted results from ArcelorMittal – Skopje and the

achieved results in ArcelorMittal – Gent. The co-

lumns marked with blue color on Figure 13 are the

delays from 2014 to 2017 in ArcelorMittal – Skopje.

The columns marked with green color are the

expected results after the application of the AM in

ArcelorMittal – Skopje. The columns marked with

orange colour are the results obtained after the

application of the AM in ArcelorMittal – Gent. The

comparative overview shows that during all years of

application of the AM the same results as in Arce-

lorMittal – Gent are expected. The second and third

application years are considered to be exceptions,

and in that period the OEE of the production line in

ArcelorMittal – Skopje is expected to increase.

Fig. 13. Comparative overview after the АО application

7. CONCLUSION

The main benefits from the TPM methodology

application are the decrease of the number of delays

of the equipment, decrease of the clients’ com-

plaints, dedicated and educated workers, as well as

improvement of the quality of the product. The suc-

cessful TPM methodology application depends on

all involved participants in the company. Mainly,

the TPM methodology is helpful in the determina-

tion and decrease of the unnecessary costs. Accord-

ing to the obtained results from this research it can

be concluded that by applying the TPM methodol-

ogy the goal is achieved, i.e. the productivity is in-

creased and the number of steel sheet metal pickling

line delays are decreased.

REFERENCES

[1] Venkatesh, J.: An Introduction to Total Productive Mainte-

nance (TPM), The Plant Maintenance Resource Center,

2007.

[2] TPM Activity report – ArcelorMittal – Gent, Transformati-

on Program ArcelorMittal-Gent, Gent, 2008.

[3] Nakajima, S.: Introduction to Total Productive Mainte-

nance (TPM) (Preventative Maintenance Series), Cam-

bridge, MA, Productivity Press, 1988.

[4] Moradizadeh, H.: Overall Equipment Effectiveness and

Overall Line Efficiency Measurement Using Intelligent

Systems Techniques, University of Regina, April 2014.

[5] Kennedy, R.: Plant and Equipment Effectiveness, Mainte-

nance Journal, 1995.

[6] Levitt, J.: Handbook of Maintenance Management, Indus-

trial Press, 2009.

48 4953

57

75,59

70,1166,42

79,0276 77,5

0

10

20

30

40

50

60

70

80

90

Ove

rall

Eq

uip

me

nt

Eff

ec

tive

ne

ss

-ОЕ

Е (

%)

Time (years)

for period 2014-2014 AM-Skopje

results after implementation of AO in AM-Gent

expected results after implementation of AO in AM-Skopje


Mech. Eng. Sci. J., 37 (1–2), 29–40 (2019)

[7] Maggard, B.: OTPM That Works: The Theory and Design

of Total Productive Maintenance: A Guide for Imple-

menting TPM, Tpm Pr, 1992.

[8] Karlsson, U., Ljungberg, O.: Ways to Implement Total

Productive Maintenance in Europe, Proceedings of the

Second International TPM Conference, Birmingham,

1993.

[9] Gotoh, F., Tajiri, M.: Autonomous Maintenance in Seven

Steps: Implementing TPM on the Shop Floor, Productivity

Press, 1999.

[10] Ireland, F., Dale, B. G.: A Study of total productive ma-

intenance implementation, Journal of Quality in Main-

tenance Engineering, Vol. 7, Issue 3, pp. 183–192 (2001).

[11] Shirose, K.: TPM – Total Productive Maintenance: New

Implementation Program in Fabrication and Assembly

Industries in Tokyo, Japan Institute of Plant Maintenance,

1996.

[12] Willmott, P.: Total Productive Maintenance: The Western

Way, Butterworth Heinemann, Oxford, England, 1994.

[13] Wireman, T.: Total Productive Maintenance – An Ameri-

can Approach, Industrial Press, New York, 1991.

[14] Bamber, C., Sharp, J., Hides M.: Factors affecting success-

ful implementation of total productive maintenance: A UK

Manufacturing Case Study Perspective, Journal of Quality

in Maintenance Engineering, Vol. 5, No. 3, pp. 162–181

(1999), https://doi.org/10.1108/13552519910282601

https://doi.org/10.1108/13552519910282601




Received: May 28, 2019 UDC: 658.5:621.382.049.76]:519.86

Accepted: June 25, 2019


SIX SIGMA METHODOLOGY – TOOL FOR IMPROVING THE CAPABILITY

OF THE PRODUCTION PROCESS

Elena Papazoska1, Gligorče Vrtanoski2

1 MSc Student at the Faculty of Mechanical Engineering, “Ss. Cyril and Methodius” University in Skopje,



[email protected]

A b s t r a c t: Modern industrial production companies on a global scale over the past decade have been facing

sectoral challenges in terms of competitiveness, reducing production costs and increasing the quality of products and

services. This challenge is especially focused on investing in scientific, systematic models for development, monitoring

and maintenance of production facilities, but always the main emphasis is on the sustainability of quality in the condi-

tions of rapid expansion of the global market and automation of the industry. Topic in this paper is Six Sigma Method-

ology. Six Sigma is statistical methodology for normalizing process and a methodology that is data-driven and customer

focused, highly disciplined process that help develop and deliver near perfect product and services. Results of research

in this paper, the practical example, clearly show the importance of the sistematic analysis and usage of the Six Sigma

methodology in the productive processes with DMAIC method for stabilization, improvement and reduction of standard

deviation.

Key words: 6 sigma; black belt; depanelization; printed circued board (PCB); DMAIC

МЕТОДОЛОГИЈАТА ШЕСТ СИГМА – АЛАТКА ЗА ПОДОБРУВАЊЕ НА СПОСОБНОСТА

НА ПРОЦЕСОТ НА ПРОИЗВОДСТВОТО

А п с т р а к т: Современите компании за индустриско производство на глобално ниво во последната

деценија се соочуваат сo сериозни предизвици од аспект на конкурентност, редуцирање на трошоците за

производството и зголемување на квалитетот на производите и услугите. Овој предизвик е посебно насочен

кон инвестирање во научни, систематски модели за развој, следење и одржување на производните капацитети,

а секогаш главен акцент е ставен на одржливоста на квалитетот во условите на брзата експанзија на глобалниот

пазар и автоматизацијата на индустријата. Во трудот е претставена методологијата шест сигма. Шест сигма е

статистичка методологија за нормализирање на процесот, а наедно и методологија ориентирана кон податоци

и клиенти за високо дисциплинирани процеси кои овозможуваат постигнување услуги и производи кои се

стремат кон совршенство. Резултатите од истражувањата во овој труд, поточно квантитативното подобрување

добиено со практичниот пример, ја посочуваат важноста на систематското анализирање и на примената на

методологијата 6 сигма во производствените процеси преку методот DMAIC за стабилизирање, подобрување

и намалување на стандардната девијација.

Клучни зборови: 6 сигма; црн појас; депанелизирање; печатено електронско коло (ПЕК); методологија DMAIC

1. INTRODUCTION

The research carried out in this paper relates to

the 6 Sigma methodology and its practical applica-

tion in the production process. The main goal is to

demonstrate the importance and the benefit of im-

proving production processes through the applica-

tion of the 6 Sigma methodology.

The implementation of the 6 Sigma methodol-

ogy will be explained by the five phases of a real


42 E. Papazoska, G. Vrtanoski

Mech. Eng. Sci. J., 37 (1–2), 41–54 (2019)

practical example, and in order to achieve a reduc-

tion in the number of defective outputs from it.

In the first phase, define phase, explains the

importance of setting a measurable target for the

project. Proportionately predicts improvement and

a clear direction for the movement of the team that

will prepare the project, its selection and the special

role of all the members. It is also analyzed according

to which parameters it is chosen whether the project

should be developed using the 6 Sigma methodol-

ogy.

In the second phase, measure phase, the dia-

grams WPI-input-process-output and the basic pro-

cess flow diagram are presented [5].

Initially, the validation of the measuring tool

that the team selected for use in measuring the exit

from the process, as well as all the conditions that

need to be fulfilled, is presented. Their quantitative

values are displayed and analyzed in the Minitab

software package [2] which gives the acceptance of

the measurement system. The parameters that

should be measured as a way out of the process are

also defined. At this stage, tests for stability, nor-

mality and ability of the process are shown.

In the third phase, the analyze phase provides

an overview of the cause-effect diagram used to

identify the potential causes of the defect to be elim-

inated. In particular, the way in which the causes,

i.e. the reasons that can be controlled and the rea-

sons that can not be controlled, are shared. To elim-

inate potential causes, the "5 Why" tool (the tool

that continuously asks "Why" until the problem is

reached) and by analyzing the other reasons with the

tests of the 6 Sigma methodology and the Design of

Experiment (DE), and hypothesis testing [5].

The next phase of the 6 Sigma methodology is

the improve phase shown through the performed

setting of the improvement parameters and the way

how to validate the selected solution.

Control is the last phase that represents the

way how to control the improved process and how

to set up solid controls for the solution to stay set for

the process for which it has been defined.

2. THEORETICAL CONCEPT OF 6 SIGMA

METHODOLOGY

Interesting fact is that despite the great interest,

available literature, research, international confe-

rences, workshops and seminars, each company has

its own specific method and method of applying the

6 Sigma methodology.

Six Sigma methodology refers to the orienta-

tion towards finding and eliminating the causes of

variation in the processes. Also 6 Sigma develops

an alternative that will lead to a reduction in varia-

tion. Six Sigma seen from an organizational level is

a quality management structure that focuses on con-

tinual improvement of four key areas [7, 8]:

➢ understanding and managing the require-

ments of customers,

➢ streamlining the key processes to the desired

results,

➢ using a large amount of data to analyze in

order to minimize variation in key

processes,

➢ fast and constant improvements in business

process.

Six Sigma as a quality management tool also

includes metrics and methodology. That largely

contributed to a marked success is the fact that the

result of the improvement can be quantitatively ex-

pressed in number of defects and savings in money

[7, 8].

When implementing the 6 Sigma model there

are certain conditions that need attention and

fulfillment increases the chances for success of the

6 Sigma initiative, which are [10, 11]:

➢ support from top management.

➢ organizational structure.

➢ application of advanced statistical tech-

niques,

➢ developing ways to reward 6 Sigma team.

The goal of 6 Sigma is to generate an improve-

ment in the performance of an organization that

aims to determine based on the requirements of its

customers at which level of Sigma is appropriate the

operation of the process. Sometimes a 6 Sigma level

with 3.4 DPMOs is not a target for all processes due

to the financial aspect of the bet [12, 13].

Six Sigma methodology uses two different

models [3]:

➢ basic model for project – based projects in

the functioning processes (DMAIC), shown

in Figure 1, and

➢ basic model used to design new processes

and create new products or services

(DMADV), shown in Figure 2.

Six Sigma methodology – tool for improving the capability of the production process 43

Маш. инж. науч. спис., 37 (1–2) 41–54 (2019)

Fig. 1. DMAIC basic model

Fig. 2. DMADV basic model

3. APPLYING 6 SIGMA METHODOLOGY

IN REAL PRODUCTION CASE

The selected practical project using the 6

Sigma methodology shows the main benefit of ap-

plying the 6 Sigma through the results obtained

from the real case. Using the Minitab software pack-

age allows you to analyze and display the results ob-

tained from the practical example.

3.1. Define phase

The 6 Sigma project that has been developed

refers to improving the process of depanelization.

The process of depaneling of the printed circuit

board is one of the main reasons for the quality

problems and returned products by the client. De-

panelization is a production process that is placed in

the central position during production, more pre-

cisely, any defect in this process means spent time

and money from all preceding processes.

Printed circuit board (PCB) arrives in panel

and is depanelized on the milling machine.

Depaneling operation is done of combination

of manual and machine work in the next steps:

➢ Operator place PCB in the machine (Figure

3).

➢ Machine using rotation movement of the

blades perform the depanelization process.

➢ Operator take the PCBs out and throw not

needed borders as a waste material.

➢ Operator visualy checks depanelization

quality.

Fig. 3. Printed circuit board (PCB) in panel

Milling machine produces defective products

(Figure 4) which can not be completely detected in

the production scope and as such are sent to the cli-

ent.

3.1.1. Problem statement

Inside process of depanelization we can notice

several risks:

➢ Improper depanelization (demaged PCB) of

the printed circuit boards.

➢ The cutting quality is checked visually after

the depanelization is performed, which does

not guarantee the assurance that only "good"

pieces will be sent to the client.

3.1.2. Project objective

The goal of the project is measurable of the

quality of the process expressed through the benefit

of the business YB and product quality expressed

through customer satisfaction from the product Yc.

This can be explained as: eliminating the defects for

the production unit and eliminating products that are

returned from the client.


Mech. Eng. Sci. J., 37 (1–2), 41–54 (2019)

Fig. 4. Defects of depanelization process

3.1.3. Selection and problem elimination

When selecting is a priority for improvement,

Pareto diagrams are used that show the need to pri-

oritize the elimination of an appropriate problem.

Data for returned products from customers, de-

fects in the production process, utilization / inexpe-

rience of production facilities, delays and others are

used as input data for analysis. However, the most

important data in the analysis are the products re-

turned by customers.

The Pareto diagram given in Figure 5 shows

the total number of monthly returned products from

customers, of which 50% belong to one product

from the entire range of products (Figure 6).

Fig. 5. Number of returned printed circuit boards from customeres


Маш. инж. науч. спис., 37 (1–2) 41–54 (2019)

Fig. 6. Number of returned printed circuit boards of the analyzed product

With deeper analysis we can see which internal

process is giving most defective non-wanted type of

products which are main reason for customer

returns. This is shown on the Pareto diagram on Fig-

ure 7, where we can observe number of montly cus-

tomer returns due to depanelization process of the

selected product.

Fig. 7. Number of returned PCB of the analyzed product per months


Mech. Eng. Sci. J., 37 (1–2), 41–54 (2019)

It is obvious that by eliminating deviation in

the process of depanelization, improvement is

made. This will reduce the number of returned prod-

ucts by the client by 60%, which would increase cli-

ent satisfaction, confidence and the success for fur-

ther cooperation.

3.2. Measure phase

3.2.1. Diagrams for clarifying the process

Measure phase is closely connected with ana-

lyze phase. This phase contains several crucial ele-

ments, such as selecting a proper correct measure-

ment system (MS, gage), a method of measurement,

trained personnel to perform the measurement, and

selecting an appropriate measurable product that

will clearly reflect the problem. Later this measura-

ble will be used through the phase analysis and

phase control. That's why the team's versatility and

their specific knowledge of production play a key

role here.

In the measure phase, it is decided what will be

measured and the validation of the measuring sys-

tem is carried out.

At this stage, the goal to be achieved by the

client YC1 and the business YВ1 is set.

The improvement expected to be achieved by

the team is the reduction of the products returned by

the client and the reduction of the production de-

fects. They are:

➢ YC1 = reduce customer return for the milling

defects due to not proper cutting (x-axis and

y-axis dimensions) for 100%. ➢ YВ1 = reduce internal scrap for the milling de-

fects due to not proper cutting (x-axis and y-

axis dimensions) for 90%.

In addition to defining the goal of the business

and the client, the goal to be achieved from the

corresponding process is also defined YP1:

➢ YP1 = distance between two dots of the

printed circuit board (dimensions of x-axis

and y-axis).

The Input-Process-Output diagram shown in

Figure 8 provides the input attributes, the main

process and the output attributes of the system being

analyzed.

The 6 Sigma methodology always provides

more reliable results if the variables of the automatic

processes are analyzed, rather than from the manual

ones. This is because automated processes are sub-

ject to greater variation.

Fig. 8. Input-Process-Output diagram

The initial flow of the process is presented in

the diagram shown in Figure 9 which purpose is to

have a visual display of the process.

In this process there is only one automatic op-

eration to which the improvement is expected later.

3.2.2. Determinating and validation

of the measure system

The next step is to determine the measurement

system that will be used in the phase of measuring,

improving and validating the solution.

First, Gage R&R is being developed to imple-

ment validation of the measurement system. In this

case, ten printed electronic circuits (PCBs) and two

operators (employees who have previous experi-

ence with manipulating the measuring machine).

The graphical display for validating the mea-

surement system given in Figure 10 clearly shows

that there is an insignificant variation between the

operator one (1) and the operator two (2) in the

execution of the measurement process, but also that

there is an insignificant variation between the

printed circuit boards (PCB) in all four measure-

ments performed.

In the part of the numerical display of the val-

idation of the measurement system, the number of

categories is 30 which is greater than 5 (30 > 5).

This proves that the selected measurement system is

suitable for measurement.

The most complicated point of the printed cir-

cuit board (PCB) or precisely the distance between

the two closest points and the same is used to meas-

ure it.

Input

PCB in panel

Milling force(electric power)

Process

Depanelizing PCB

Output

PCB depanelized

Borders waste


Маш. инж. науч. спис., 37 (1–2) 41–54 (2019)

Fig. 9. Process flow diagram

Fig. 10. Grafical table for validation of the measurement system


Mech. Eng. Sci. J., 37 (1–2), 41–54 (2019)

For the appropriate data obtained in the meas-

urements, it can be decided that the measurement of

the PCU samples used in the process can be

performed by x-axis and y-axis measurements to

cover all directions of depanelization. This is shown

in Figure 11.

Fig. 11. Technical drawing of PCB with x and y dimensions with tolerances

3.2.3. Normality tests, control diagram and

capability tests for the process by x-axis and y-axis

By measuring the dimensions of 30 printed

electronic circuits along the x-axis and the y-axis,

the normality test, the control diagram and the capa-

bility test were made. All tests are made at panel

level.

The normality test given in Figure 12 shows

that the process is not normal, p < 0.005, for the x-

axis, and the process is normal, p = 0.184, for the y-

axis.

The control diagram given in figure 13 shows

that the process is stable, in fact, none of the groups

of printed electronic circuits (with a group of two

circuits) does not go beyond the x-axis and y-axis

control limits. In particular, only one group is at the

x-axis limit value.

Capability test of the process given in Figure

14 shows that the process is not capable, Cpk = Ppk

(because the process is not normal) = 1 for the x-

axis and the process is not capable, i.e. Cpk = 0.97

for the y-axis .

Fig. 12. Normality test for x-axis and y-axis


Маш. инж. науч. спис., 37 (1–2) 41–54 (2019)

Fig. 13. Control diagram for x-axis and y-axis

Fig. 14. Capability test for the process for x-axis and y-axis

With analyzing panel level information

received does not provide a complete picture of the

process, so 6 Sigma team concludes that it is

necessary to analyze the printed circuit board level

with the possibility to get more detailed information

about the process of depaneling.

After the conducted analysis it was concluded

that the measurements will have to be divided indi-

vidually for each printed circuit board.

On the basis of the obtained observations, con-

trol diagrams for all printed electronic circuits are

made, starting from the first to the sixth printed cir-

cuit board respectively, according to the x-axis and

the y-axis.

With the detailed control diagrams made in x-

axis and y-axis, each printed circuit board individu-

ally shows that the process is not stable in x-axis for

the printed circuit boards PCB 3, PCB 5 and PCB 6,

while along the y-axis for all six printed circuit

boards on the panel (Figure 15).

With this kind of analysis and result 6 Sigma

project can not continue, until the variation in the

depanelization is eliminated.

3.2.4. Stabilizing the process and repeated tests

for the normality of the process

The nature of the 6 Sigma methodology re-

quires a stable process before starting the analysis


Mech. Eng. Sci. J., 37 (1–2), 41–54 (2019)

and the process of improvement. The process should

produce stable-predictable, more precisely defec-

tive products to appear consistently.

The 6 Sigma team is focused on analyzing the

process and finding the cause of instability and var-

iation in the process. After the analysis of the pro-

cess, it was concluded that there was too much vi-

bration of the panel on the support, which is placed

along the y-axis of the milling machine. A solution

is proposed that could reduce vibration by increas-

ing the diameter of the supporting pins of the sup-

port on the dimensions Φ3.9 mm and Φ2.85 mm.

With this change in the support, it is expected that

the panel will occupy a more secure position, with

less vibrations during depanelization, and thus re-

duce the variation between the cuts. New pins were

made and placed on the support for the panel of the

machine for depanelizing. This is shown in Figure

16.

Fig. 15. Control diagrams for x-axis and y-axis (PCB1)

Fig. 16. Machine support for depanelization with marked changed pins


Маш. инж. науч. спис., 37 (1–2) 41–54 (2019)

After the change made to the pins, it is neces-

sary to depanelized the new panels in a total of 30

printed circuit boards. For them, control diagrams

are made to confirm whether there is a reduction in

the variation in the process. In doing so, a re-analy-

sis of the control diagrams is performed for all

printed circuit boards respectively in the x-axis and

in the y-axis.

With the detailed control diagrams made in the

x-axis and in the y-axis for each printed circuit board

respectively, it is shown that the process is stable in

x-axis and in the y-axis for all the printed electronic

circuits on the panel.

With this obtained result, the 6 Sigma project

can proceed further in implementing the steps of the

6 Sigma methodology.

3.2.5. Capability tests for the process

for x-axis and y-axis

Next is the elaboration of the tests for the abil-

ity of the x-axis and y-axis depanelization process

for all six panel positions individually for the

printed circuitry from PCB 1 to PCB 6. The capa-

bility of the process and the corresponding coeffi-

cients are given summarized in Table 1, whereby it

can be verified that the process is not capable of

proper depanelization of any position from the ex-

isting six on the panel, both in the x-axis and the y-

axis.

T a b l e 1

Cpk results for capability for PCB 1 to PCB 6


Cpk x y

1 1.21 1.89

2 0.22 2.02

3 1.70 2.10

4 0.09 1.86

5 1.40 –0.77

6 0.23 –0.16

Accordingly, it can be concluded that the

process of depaneling is an appropriate candidate

for further analysis and improvement in order to

enable it to produce the consistently required

standards.

3.3. Analyze phase

Analyze phase is the most comprehensive

phase that requires critical thinking and great dedi-

cation. At this stage 6 Sigma team must work as an

individual with a common goal and devote suffi-

cient time to the 6 Sigma project whenever neces-

sary.

In the analyze phase, in the implementation of

the appropriate required experiments, such as the

DOE, there may be defective products, so in no case

6 Sigma team should not start the 6 Sigma project

without the presence of a process expert. Also, it is

necessary that all affected competent individuals are

informed that on the process there is ongoing 6

Sigma project for smooth analysis and improve-

ment.

The first step that 6 Sigma team does at this

stage is analyzing with the brainstorming and using

the diagram fish bone. Figure 17 shows the fish

bone diagram for the depanelization process, ana-

lyzing the four elements of the process: people, ma-

chine, materials and methods.

For each of these elements the 6 Sigma team

sets out the reasons that are probable possibilities to

be the reason for the variation and malfunctioning

of the panel.

By using the analysis WHY-WHY part of the

possible reasons for variation divided by categories

is rejected.

By eliminating some of the potential causes of

malfunctioning and producing defective printed

electronic circuits, there are still three potential

causes (X1, X2 and X3) that need to be further ana-

lyzed.

3.4. Improve phase

From the analyze phase using DOE and hy-

pothesis tests it has been determined that all three

analyzed factors have an impact on the process of

depanelization, and that factor B: speed of depanel-

ization on the very process of depanelization in the

x-axis and along the y-axis; and the factors A: z-

axis; and C: fixation on the standard deviance.

All three factors need to be set at a minimum

level to obtain the most accurate and stable process

of depanelizing.

By setting the factors to a minimum level, sev-

enteen (17) panels were depanelized to confirm the

reduction in standard deviation. In this case, an anal-

ysis of all positions in the x-axis and along the y-

axis was performed on all six positions of the PCB

on the panel. With the results obtained, it can be

concluded that by adjusting all three factors to a

minimum level, a process of depanelization is ob-

tained with a significantly lower standard deviation


Mech. Eng. Sci. J., 37 (1–2), 41–54 (2019)

for all 6 (six) PCP positions in the panel and it is

decided that this set of factors should be introduced

into the production control plan, in order to start

batch production with the changed factors.

Fig. 17. Fis-hbone diagram for depanelization process

3.5. Control phase

The control phase takes place in a test period

of one month, as follows: on a daily basis the quality

department notice a fall in the defectively depene-

trated PCU and on a weekly basis if the client does

not return the PCU with a defect of depanelization.

At this stage, it is crucial to monitor the process on

a daily basis in order to detect all the variations, and

with slightest problem occurs the factors and im-

provement will be compromised and the process

part will be restored to a dead end.

Internally by the team it is necessary to take 3

(three) randomly selected PCUs on a daily basis and

take measurements within a month.

With the daily results obtained during the con-

trol month, backward tests of capability and control

diagrams were performed. The results are shown in

Figure 18 in the x-axis and on the y-axis, corre-

sponding to all 6 (six) positions of the PCB on the

panel.

Fig. 18. Capability tests for all six positions for x-axis and y-axis for PCB1


Маш. инж. науч. спис., 37 (1–2) 41–54 (2019)

An increased process capability for all 6 (six)

positions is seen, as shown in Table 2.

T a b l e 2

Срк capability results for PCB 1 to PCB 6


Cpk x-axis y-axis

1 2.52 3.16

2 1.58 2.80

3 1.22 2.19

4 1.39 2.64

5 1.44 0.66

6 1.39 0.67

3.6. Analyze and improvement

By analyzing the control diagrams given in

Figure 19 and in Table 3, it is found that the process

is with narrower boundary values and with reduced

standard deviation.

In none of the positions there is no unit that

comes out of the control boundaries. With these an-

alyses 6 Sigma project is closed and is proclaimed

for successfully implemented 6 Sigma improvement

project.

Fig. 19. Control diagrams before-after for PCB1 to PCB6 for x-axis and y-axis

T a b l e 3

Standard deviation values before-after

for PCB1 to PCB6

The same variation is analyzed on all the same

machines that are installed in the production capac-

ity and the stabilization of them is applied subse-

quently.

Additionally, 6 Sigma team reviewed the key

parameters that affected the incorrect depaneliza-

tion and produced a matrix to monitor the change in

parameters in the current production, which is filled

in and updated by the responsible engineers.

4. CONCLUTION

By applying the 6 Sigma methodology, the

company has the opportunity by reducing defects

Standard deviation values before-afte

Before After Before After

X1 0.26 0.13 Y1 0.26 0.16

X2 0.53 0.21 Y2 0.25 0.14

X3 0.25 0.17 Y3 0.22 0.12

X4 0.37 0.17 Y4 0.31 0.13

X5 0.35 0.19 Y5 0.24 0.23

X6 0.32 0.22 Y6 0.27 0.24


Mech. Eng. Sci. J., 37 (1–2), 41–54 (2019)

and variations to become more competitive on the

market and to establish a suitably acceptable relati-

onship with its customers by delivering products

and/or services that have the required quality and

timely delivered or performed.

The practical example demonstrates the ability

of the 6 Sigma methodology to stabilize and im-

prove the production process. It is delicate enough

to be enhanced during the day-to-day adjustment of

parameters or be enhanced with tools that contain a

lower level of statistical analysis.

Using the DMAIC model in the 6 Sigma meth-

odology helped the team in improvement of the

process of depanelization through stabilization of

the process was carried out, narrower limit values

were obtained at all PCB positions and a significant

decrease in the standard deviation by up to 50% for

part of the positions.

The very improvement of the product and the

machine for the depanelization in the production

capacity has been analyzed and replicated as a good

practice of all the same machines for the entire

range of products.

The fixing and placement of the z-axis of the

tool is implemented in the same way for all products

and machines while the speed of depaneling is ad-

justed depending on the material of the product, its

defective category and production capacity. This

shows that the 6 Sigma methodology is powerful

enough that results obtained from one improvement

can be replicated and standardized on processes that

are of the same nature as the one subjected to anal-

ysis.

REFERENCES

[1] McCarty, T., Daniels, L., Bremer, M., Gupta, P.: The Six

Sigma Black Belt Handbook, McGraw-Hill, 2004.

[2] Minitab софтверски пакет, верзија 17, Minitab Inc,

USA.

[3] Papazoska, E.: Application of the 6 Sigma Method to Im-

proving the Capability of the Production Process, Master

thesis, UKIM, Faculty of Mechanical Engineering,

Скопје, June 2019 (in Macedonian).

[4] Sheehy, P., Navarro, D., Silvers, R., Keyes, V., Dixon, D.,

Picard, D.: The Black Belt Memory Jogger: A Pocket

Guide for Six Sigma Success, Goal/QPC, January 2002.

[5] Wiklund, H., Edgeman, R.: Six sigma Seen as a Methodo-

logy for Total Quality Management, Measuring Bussiness

Excelence, March 2001.

[6] Henderson, R. G.: Šest Sigma Quality Improvement with

Minitab, A John Wiley & Sons, Ltd Publications, 2011.

[7] Lazibat, T., Baković, T.: Šest sigma sustav za upravljanje

kvalitetom, Znanstveni časopis za promicanje kulture

kvalitete i poslovne izvrsnosti, Vol. 1, No. 1, pp. 55–66

(2007).

[8] ISO 13053-1: Quantitative methods in process improve-

ment – Six Sigma, Part 1: DMAIC methodology, 2011.

[9] ISO 13053-2: Quantitative methods in process improve-

ment – Six Sigma, Part 2: Tools and techniques, 2011.

[10] ISO 18404: Quantitative methods in process improvement

– Six Sigma. Competencies for key personnel and their or-

ganizations in relation to Six Sigma and lean implementa-

tion, 2015.

[11] http://www.asq.org/topics/sixsigma.htm (accessed on 15.

01. 2019).

[12] Milosavljević, P.: Six Sigma Metoda, Mašinski fakultet u

Nišu, Srbija, Oktober 2016.

[13] Wilson, D., Wiltsie, P.: PMPA – Lean Six Sigma tools and

methods, 2005 (https://www.pmpa.org/docs/defaultsource

/technical-conference/09-today%27s-quality-lean. Pdf?sf

vrsn=0) (accessed on 15. 01. 2019).

[14] Lazić, M.: Six Sigma – Metodology for quality improve-

ment, Quality Festival, Kragujevac, Serbia, May 2011.

http://www.asq.org/topics/sixsigma.htm

https://www.pmpa.org/docs/defaultsource%20/technical-conference/09-to%1fday%27s-quality-lean.%20Pdf?sf%20vrsn=0






Received: July 9, 2019 UDC: 005.61:519.86]:368

Accepted: September 1, 2019


PROCESSES OPTIMIZATION AND REDUCTION OF OPERATIONAL COSTS

– CASE IN INSURANCE COMPANY –

Vesna Gjorčeva1, Gligoče Vrtanoski2




[email protected]

A b s t r a c t: The insurance industry is mainly based on its primary activity which is exercising the right to claim

payment in case of insured case occurrence, arising unexpectedly as a sudden event, not in any way related to the will

of the insured. For this purpose, work organization in an insurance company implies application of a complex and well

designed system of activities and processes. Each separate process should be functional in both directions. The first

one should be directed towards itself, thus providing high quality performance of the planned process activities. The

second one is to be focused on its complementary functioning together with the remaining processes included within

the insurance business. Clearly defined processes, based on empirical techniques and methods contribute to greater

effectiveness and efficacy which result in greater profitability as a final objective in the work of one insurance company.

The research in this paper aims to ascertain the impact of improved processes of operational cost reduction and increase

of profitability as the ultimate goal.

Key words: insurance industry; business processes; sales; claims; organization; synergy; efficiency; effectiveness

ОПТИМИЗАЦИЈА НА ПРОЦЕСИТЕ И НАМАЛУВАЊЕ НА ОПЕРАТИВНИТЕ ТРОШОЦИ

– СЛУЧАЈ ВО ОСИГУРИТЕЛНА КОМПАНИЈА –

А п с т р а к т: Осигурителната индустрија начелно се базира на својата примарна активност: остварување

на правото на осигурениците за надомест на штета која настанала како резултат на ненадеен, од волјата на

осигуреникот независен осигурен случај. За таа цел, организацијата на работењето на една осигурителна ком-

панија подразбира комплексен и пред сè добро осмислен систем на активности и процеси. Секој одделен процес

треба двонасочно да биде функционален. Еднаш во насока на функционирање сам за себе, со што би се обез-

бедило квалитетно извршување на планираните процесни активности, и еднаш во насока на негово комплемен-

тарно функционирање со другите процеси од дејноста. Добро дефинираните процеси, димензионирани врз

основа на емпириски техники и методи, придонесуваат за поголема ефикасност и ефективност, а со тоа и за

поголема профитабилност како крајна цел на дејствувањето на осигурителното друштво. Истражувањата од

овој труд имаат за цел да го констатираат влијанието на подобрените процеси врз оперативното намалување

на трошоците и зголемување на профитабилноста како крајна цел.

Клучни зборови: осигурителна индустрија; деловни процеси; продажба; штети; организација; синергија;

ефикасност; ефективност

1. INTRODUCTION

The subject of this research are the analyses of

a part of the sales processes, specifically those re-

ferring to their administration and management, as

well as their improvement, whose ultimate goal is to

increase profitability.

The insurance industry is basically based on its

primary activity which is exercising the right of the

insureds to be compensated for the damage occur-

ring as a result of a sudden, unexpected insured

event as opposed to their will or intention. For that

purpose, the organization of the work operations in


56 V. Gjorčeva, G. Vrtanoski

Mech. Eng. Sci. J., 37 (1–2), 55–64 (2019)

one insurance company includes a complex and

primarily well-designed system of activities and

processes. Each separate process should function in

both directions. Namely, its first instance would be

functioning for itself, which would ensure the qual-

ity execution of the planned process activities; sec-

ondly in the direction of its complementary opera-

tion together with the other business processes.

Processes can be divided into core business

processes and auxilliary processes.

Essential processes include [1, 11]:

• Sales processes.

• Underwriting processes.

• Processes for assessment and claim settlement.

• Processes for claims in court proceedings.

Auxiliary processes are [1, 11]:

• Financial processes.

• Legal processes.

• Employee management processes.

• IT processes.

• Control processes.

Among the sales processes and those for un-

derwriting are the processes for administering the

sales, which at the same time cover the adminis-

trative procedures for making the policies and the

policy documentation and the part of the underwrit-

ing referring to data control before the actual

issuance of the policies and their distribution.

Depending on the structure of the sales net-

work in an insurance company (size and organiza-

tion, the manner of managing the activities referring

to sales and related to data entry, their processing in

the system, and the creation of policies and policy

documentation submitted to the insured) the admi-

nistration process may be an integral part of the acti-

vities of the sales network or separate work unit

(section or a department) may be designated to

make sure it functions smoothly.

2. INSURANCE MARKET

The definition of the term market is different.

Basically, it refers to a place where the processes of

buying and selling occur. However, it also can be

defined as a ratio of supply and demand for certain

products and services. It is this kind of supply and

demand relationship that functions on the insurance

market [7].

Four main factors for the functioning of the

insurance market are [8]:

1. Need,

2. Payment ability,

3. Desire,

4. Authorization.

That is the market functions as a link between

the need of the individual or legal entity for pur-

chase of a particular insurance service (that need

may be self-initiated or prompted by a legal pro-

vision for mandatory procurement of the service),

the solvency of the individual / legal entity for the

procurement of that service, the desire to complete

the transaction and the authorization to negotiate,

purchase or sell an insurance service. The lack of

any of the listed factors prevents the functioning of

the insurance market as a whole [8]. In any case, the

existence of the insurance market is determined by

the existence and active participation of two inter-

ested parties, insurance buyers, i.e. potential in-

sureds, on the one hand, and insurance vendors, or

insurers, on the other.

2.1. Market potentials and targeted

insurance sales

The potential of the insurance market are all

existing insureds who have purchased an insurance

policy of a different type or a class of insurance and

which they intend to renew, as well as those who

have all the prerequisites to become insured, and

have still not bought an insurance policy. In order to

acquire approximate data on the potential of the

insurance market, market research has to be carried

out in order to provide answers to several key issues,

as shown in Figure 1 [7].

The answers to these questions have a major

impact on the structure of the portfolio of one insur-

ance company and the organization of sales chan-

nels.

Defining the most appropriate offer for a target

group of people or individuals that are deployed in

different territorial units is the basis for the targeted

sale of insurance products. With the registration of

the insurance company itself, the market potential

or the target group of that company has been already

determined. Thus, the insurance company that sells

life insurances has a different target group from the

company that is registered for the sale of non-life

insurance.

Companies registered for reinsurance aim at

insurance companies on the market which can trans-

fer the surplus risks to a reinsurance company thus

protecting their solvency.

Processes optimization and reduction of operational costs – Case in insurance company 57

Маш. инж. науч. спис., 37 (1–2), 55–64 (2019)

Fig. 1. Insurance market potential [7]

In each of these cases, market potential lies in

the same groups of people or individuals who buy

different insurance products, only in different roles.

Namely, one can potentially insure his/her property,

professional liability, health and life. However, this

is not entirely finalized, that is, the buyer can once

appear as an insured who insured the home, in an-

other case the car, next time the same insured can

buy an accident or health insurance policy, etc. So,

the diversity of supply and the multiplied role of the

potential insured makes the diversification of the

market potential towards a particular target group a

complex and a dynamic process that often changes,

and therefore requires the insurance companies to

constantly monitor those changes and offer an ap-

propriate and timely response.

The insurance market allows mass access only

to certain types of insurance. These are, as a rule,

obligatory types of insurance or insurance that is

traditionally accepted on a particular market (some-

where it is household and family insurance, some-

where group personal accident insurance [10]. The

sale of this type of insurance is carried out through

standardized forms and ways enabling coverage of

the overall insurance market [7].

All other types of insurance require a diffe-

rential approach on the market. The practice shows

that when it comes to voluntary insurance of pro-

perty, liability or life insurance, insured persons

have different needs, desires and interests. In order

to respond adequately to such requirements, the ins-

urance companies constantly upgrade their product

portfolio and promote the level of the services they

offer. In order to achieve a better access on the insu-

rance market, it is inevitable to make market seg-

mentation on different grounds (territorial, demo-

graphic, etc.) in order to meet the requirements of

the clients (insureds), which will ultimately contri-

bute to the increase in sales. A typical example of

this is the territorial segmentation based on a preli-

minary analysis of the results of sales of a particular

product to a particular territorial unit.

3. PROCESSES IN INSURANCE SALES

It is extremely important that the process of

selling insurance policies, burdened with all the

complexity previously elaborated, is thoroughly

planned because it is most closely related to the

success of the insurance company. Even if all other

aspects of management, planning, communication,

marketing, claims, finances etc., are organized im-

peccably, yet the sales process does not function

properly, the company will not show satisfactory re-

sults.

This is the most important reason to create a

detailed sales process that provides all the necessary

steps, tasks and levels of responsibility that will lead

to maximum efficiency and effectiveness.

The sales process should be simple and well

defined. This is the key to a successfully executed

selling process, which will eventually turn the op-

portunity into a factual client. For this purpose, the

first step in defining the process, the mapping,

Market potential

Who are the participant on the Market?

What do clients mostly

puchase?

Why do clients buy certain products?

Who most frequently

buys a certain product?

How does the sales take

place??

When do the clients buy?

Where does the sales mostly

happen?


Mech. Eng. Sci. J., 37 (1–2), 55–64 (2019)

should be performed by analyzing the basics of the

process through 5 key words: Who (Which), Where,

When, How and Why [9]. Mapping, in fact, should

answer questions that begin with the stated words

and through those responses, it will determine the

efficiency of the process and its further steps.

When the mapping is completed and answers

to all questions are evident encompassing the entire

process cycle from start to finish, including all the

auxiliary processes, the methods for successful

planning of the sales process needs to be defined. It

should be noted that whenever sales are discussed,

due to its natural connection with marketing, these

two processes are considered simultaneously and

when planning the same, this mutual relation must

be taken into consideration [9].

The methodology of the sales planning process

is based on several postulates. Below is the list of

the most important ones in order to obtain a well-

planned process [9, 11]:

▪ Repetition of steps – In the world practice, only

2% of sales are successfully completed after the

first contact. This means that more contacts are

required, more sales interviews and, finally,

more steps in the sales process are needed to

conclude the sale. For even 80% of sales, it

takes five to eight contacts to conclude the deal.

This means that if you contact a potential buyer

or customer less than five times or more than

eight times there is a high probability that there

is a problem with repeating the steps. Therefore,

it is necessary for a specific sales process to ac-

curately define the optimal number of steps that

are repeated until the conclusion of the sale.

• Efficiency of the sales process – Time kills

purchase deals. The speed at which the potential

buyer turns into a customer and the number of

potential customers that need to make that

change determines the efficiency of the sales

cycle. In order to achieve greater efficiency, the

right steps need to be taken to measure this pe-

riod of time required for such change from a po-

tential buyer to a client. This results in loss re-

duction since the number of those potential buy-

ers who became clients becomes bigger which

has positive effects on the profit.

• New versus existing customers – Profitability

of a client who has concluded an insurance con-

tract over a certain period of time determines the

time cycle for successful sales. Insurance com-

panies spend much more time getting new cus-

tomers than keeping the existing ones. In fact, it

is very likely that existing customers will re-buy

a policy, that is, to renew their existing one, to

buy an additional product and spend more

money. In that way they have bigger potential to

become even more profitable. Hence, knowing

the time cycle for successful sales, you can de-

termine the amount of funds that should be spent

on a particular segment of potential buyers.

▪ Predictability of requirements – Every sale

takes place in cycles, so the sale of policies is no

exception to this rule. This means that when

planning the process, the time of the sales cycle

and the variations of that same cycle should be

monitored in order to predict the loyalty of the

buyer as accurately as possible. Knowing the

time of the policy renewal of already existing

buyers, it becomes certain and provides an

opportunity for a quantitative and qualitatively

improved offer.

• Brand awareness – In order to preserve the

structure of the sales portfolio in a good condi-

tion, a high level of brand recognition and the

solutions that it provides should be constantly

maintained. In that direction, much more attenti-

on should be paid to constantly improve and

maintain a certain level in reference to public

relations since they are much more important

and should be treated with greater care as com-

pared to the classical marketing approach in

advertising certain products. Especially in in-

surance, where the recognizable quality of a par-

ticular brand, whether it's a company, a brand

product, or a brand service, brings a lot more

clients than advertising that is just spending

money. When it comes to insurance marketing,

it's more important to increase the positive

brand recognition and the good reputation of the

insurance company than to increase the funds in

the advertising budget.

• Reduction on discounts – Although the most

commonly used tool in selling insurance on our

market, discounts are disadvantages in sales and

advertisements of the insurance products and

services. It would be best if they are used occa-

sionally, only when other sales methods fail. In-

stead of using discounts, the reason that creates

the need for it needs to be discovered as well as

to make an effort to locate and remove such

reason from the selling process. If that is ren-

dered impossible, then it needs to be replaced it

with an improved offer. A potential buyer or an

existing one who wants to renew the policy sho-

uld be offered added value and this should lead


Маш. инж. науч. спис., 37 (1–2), 55–64 (2019)

him to focus on the improved offer rather than

the discount.

• Trained sales agents – Nothing sells better than

a well-trained seller. The constant training of

insurance sales agents is imperative. They must

at any time improve their knowledge about

products, the way they are presented, improve

their negotiating and sales skills. In this way

they will be able to improve their effectiveness.

That will increase their morale at the same time

improving the profitability of the company. This

would be a winning combination for everyone

included in the insurance business.

To sum up, well defined sales processes can

increase the effectiveness through reduction of non-

efficient selling programs.

3.1. Division of sales processes

The division of the selling process may be

based on [3, 11]:

• the type of distribution channel through which

the sale is made,

• defined separate operating units for execution of

sales.

The type of distribution channel defines the

steps in the process, their interdependence and the

duration of their execution. Depending on the struc-

ture of the distribution channel, the process can be

simple, with a small number of involved stakehold-

ers and with a small number of steps, as in the case

of direct sales. This process is shown in Figure 2.

Fig. 2. Process of direct sales in insurance

4. ADMINISTRATION PROCESS

OF INSURANCE POLICIES

AND POLICY DOCUMENTATION

Sales processes and underwriting processes are

essential processes for the functioning of one insu-

rance company. The part of the underwriting pro-

cess, which is actually a continuation of the sales

process, is the process of administering policies and

policy documents. This process at the same time

covers administrative procedures for the preparation

of policies and policy documents and the underwrit-

ing section relates to data control before issuance of

policies and their distribution. Furthermore, it tracks

the policy and ultimately finalizes with the return of

the verified policy documentation in the insurance


Mech. Eng. Sci. J., 37 (1–2), 55–64 (2019)

company where it is recorded and kept in the com-

pany's archive.

Depending on the structure of the sales net-

work in an insurance company, its size and orga-

nization, the manner in which sales activities are

managed pertaining to the data entry, their proces-

sing in the system and the production of the policy

documentation, the administration process can be an

integral part of the sales network activities. Additi-

onally, the administration process may be delegated

to a separate working unit (service or sector) in the

insurance company.

Below is a presentation of data and findings

from the analysis of a typical example of policy

administration and policy documentation of are

insurance company, where a separate work unit has

the responsibility to run this process.

The reviewed period covers a time span of 10

consecutive years, in which two working units

merged into one, rationalization of the work

activities and jobs was done, the parts of the process

related to the use of application software were

improved, all these leading to reduction of total

costs.

4.1. Structure of the process

The administration process in the two re-

viewed years is with a different structure. In the in-

itial year it is more complex due to the greater

number of employees, lower utilization of applica-

tion software and other IT solutions as well as

greater volume of manual work. The latter it was

characterized with several steps in the process and

poor effectiveness, because the weight of the

process lay in manual administration and data entry

(number of employees, placement in the process), at

the expense of data control which should ensure the

process quality.

The most simplified version of this process is

shown in Figure 3 which shows the main stages of

the process that function as separate entities and

which have different dynamics in the execution of

the activities that comprise each individual unit.

The second comparative year, 2016, has a

smaller number of steps due to the introduction of

smart solutions through application software for this

kind of activities, which automatically reduces the

phases of the process, the steps of the individual

phases in the process and consequently the changed

processes, the number of employees .

Fig. 3. Structure of the process of policy administration for 2006 [11]

Legend (Explanation of the process):

• Administration – in the part of the administration, the following activities are included: reception of documentation, printing of policies

and archiving of the returned documentation from the client.

• Data entry – refers to the input of data required for creation of the computer system policy through appropriate application software.

The operator should be trained in recognizing the elements of the policy and the police documentation.

• Data control – means control of the entered data in the system, whereby, as a rule, these officers have a higher level of authorization,

which allows them to intervene in the process of making the policy.

• Archiving of documentation – the insurance company must keep a proper record of all issued policies and policy documents, because they are contracts signed by the company and by the client, and as such they are referred to as documents for an obligatory relation.

The collection of all documentation related to the policy and its archiving in accordance with the legal regulations is the task of this

unit.


Маш. инж. науч. спис., 37 (1–2), 55–64 (2019)

Fig. 4. Structure of the process of policy administration for 2016 [11]

Legend (Explanation of the process):

• Sales network – in 2016, the insurance market recognizes broad diversification in the direction of sales channels. Direct sales,

insurance brokers, agents, insurance agents, travel agencies, banks. Regardless of the source of all information from the domain of sales, they are processed in one place. This ensures the consistency of the administration process.

• Data entry – refers to the input of the data required for the development of the computer system policy through appropriate application

software. The operator should be trained in recognizing the elements of the policy and the police documentation.

• Data control – means control of the entered data in the system, whereby these officers, as a rule, have a higher level of authorization,

which allows them to intervene in the process of making the policy.

• Archiving documentation – collecting all documentation related to the policy and its archiving in accordance with legal regulations is

the task of this unit.

By comparing the two processes, it is evident

the existence of rationalization both in the process

phases and in the number of officers. The process

in 2006 is composed of four working units, while

the latter from 2016, comprises of three. The

number of officers is doubled. This is achieved with

the help of automation.

Automation in administrative processes is a

key to increased efficiency. In these processes, since

activities are largely dependent on strict monitoring

of administrative procedures, it is very simple to

replace the manual work with a systemic routine us-

ing a computer application. Also, the control mech-

anisms of the process are mostly left to the computer

system serving process. Thus, through savings in

human resources, office supplies and operating

costs, the process is streamlined.

4.2. Description of separate phases in the process

Both processes from the previous item, the one

that shows the state in the policy administration

department in 2006, and the one from 2016, have

several stages. In order to understand the impor-

tance of certain parts of the process and their impact

on rationalization, we will present them in detail as

follows.

It is evident that the 2006 process (in short

process 2006) has several stages and the activities

are performed by two units within the department.

Figure 5 shows all the elements of the process and

their connection. Such organization determines the

activities of the departments and their interdepen-

dence.

In addition to being a process with fewer sta-

ges, in the process in 2016 (in short process 2016)

changes in the steps and in the descriptions of indi-

vidual activities can be noted. The elements of the

process and their connection are shown in Figure 6.

It is evident that the department for policy

administration and policy documentation is absent.

The activities of this department are fully trans-

ferred to the data entry department and the control

department, which in the process of 2016 counts 10

officers. The archive of the documentation is a

responsibility of one operator, the team being an

accoutability of a department manager.


Mech. Eng. Sci. J., 37 (1–2), 55–64 (2019)

Fig. 5. Placement of officers in separate phases of the administration process 2006 [11]

Fig. 6. Placement of officers in separate phases of the administration process 2016 [11]


Маш. инж. науч. спис., 37 (1–2), 55–64 (2019)

4.3. Statistical indicators and analysis

The analysis of statistical indicators, as well as

the description of the individual phases of the

process, should provide a detailed picture of the

process optimization.

The following is an overview of the analysis of

the three selected parameters: reduction of the

number of employees, reduction of the salary costs

and overhead costs, consequently the automation of

the parts of the process related to renewal of policies

and policy documentation.

Table 1 shows the reduction in the number of

employees in the department, with the comparative

percentage of the two reviewed periods being 47%.

On the basis of these data, a comparison of the

salaries in both reviewed periods was made, taking

into account the average gross salary of the jobs in

the financial department with similar complexity,

and a comparative value of –27% was obtained,

which means that the reduction in the number of

employees brought savings in payroll costs of 27%

An analysis was made of overheads by policy

and salaries of the employees of the sector by

policy, and in both items significant decrease was

determined. The obtained results are shown in

Figures 7 and 8..

T a b l e 1

Comparison – number of employees and salaries

in the reviewed time spans

Number of:

Employees Salaries

2006 2016 2006 2016

Manager 1 1 – –

Administrators 6 – –

Data entry officers 8 6 – –

Control officers 4 4 – –

Archive records officers 2 1 – –

Total: 21 12 – –

–43% –27%

Fig. 7. Graph on the total number of cases per different products [11]

Fig. 8. Graph on the rationalization of overheads and cost for salaries per policy [11]

0

10000

20000

30000

40000

50000

60000

2006

2016

0

10

20

30

40

50

60

Overheadexpences/per policy

Salary/per policy Total Expences/perpolicy

2006

2016


Mech. Eng. Sci. J., 37 (1–2), 55–64 (2019)

5. CONCLUSION

Based on the conducted research it can be con-

cluded that the sales network is the driving force of

an insurance company. The better its organization

and the more educated and motivated employees

work in it, the greater and more reliable the growth

of the insurance company becomes. This logically

leads to a conclusion that in order to accomplish

planned sales, it is just as important to work on its

backup, that is, the administrative support needs to

function according to a well-designed process, with

an optimal number of officers and impeccable IT

support. It enables a high quality execution of the

activities in all stages of this two-way process, once

in the direction of efficient functioning for itself and

once in the direction of its complementary operation

with the other processes related to sales.

The presented data and results from the analy-

sis of one typical example of how policy administra-

tion and administration of policy documents is or-

ganized, are taken from an insurance company

where a separate work unit is responsible for per-

forming such operations.

They show that in the reviewed period of 10

consecutive years within which there was a merger

of two work units into one, rationalization of the

working activities and jobs was made with the

improvement of those parts of the process related to

the use of application software. The number of

process phases in general, as well as certain

individual phases is reduced. In this way, many ben-

efits have been achieved such as savings in human

resources, overheads and operating costs (salaries

and allowances). The results are as follows:

• reduction of the number of employees by 43%

and salaries by 27%,

• reduction of overheads by 54%,

• reduction of total costs by 47%.

Reduction of costs and simultaneous increase

in the volume of sales result in great effects in the

risk management process as a part of the underwrit-

ing business. Because sales and insurance processes

are half of the core processes in an insurance

company, their optimization is the key to profitable

operation of the company and the achievement of a

positive financial result.

REFERENCES

[1] Nanda, V.: Quality Management System for Product De-

velopment Companies, CRC Press, Boca Raton – London

New York Washington, DC, 2005.

[2] De Bettignies, H.-C., Lépineux, F., Tan, C. K.: The insu-

rance business and its image in society: Traditional issues

and new challenges, ABCM, 2006.

[3] Vaughan, E. J., Vaughan, T. M.: Fundamentals of Risk

and Insurance, Wiley, 2013.

[4] Miller, D.: Breaking with tradition in the insurance indus-

try: Strategies to insure operational efficiency and future

growth, Business Process Solutions, Executive perspec-

tive, OpenTex, 2011.

[5] Rejda, G. E., McNamara, M. J.: Principles of Risk Mana-

gement and Insurance, Pearson Series in Finance, Twelfth

edition, 2013.

[6] Barbir, V.: Čimbenici uspješnosti prodaje usluge osigu-

ranja, Ekonomski pregled, 55 (9–10), pp. 815–839 (2004).

[7] Njegomir, V.: Uloga finansijskih derivata u upravljanju

rizikom osiguranja, Računovodstvo, vol. 55 (2011).

[8] Nakić, S.: Menadžment prodaje usluga osiguranja, Puto-

kazi – Interdisciplinarni znanstveno-stručni časopis Sve-

učilišta Hercegovine, Vol. 1. No. 2., pp. 185–197 (2013).

[9] Anderson, C.: 8 Procedures to Take Control of Sales and

Marketing, Research paper, https://www.themanager.org/

Strategy/Procedures_3_Sales.htm.

[10] Law on compulsory traffic insurance, Official Gazette of

the Republic of Macedonia no.88/05, 70/06, 81/08, 47/11,

135/11, 112/14 and 145/15.

[11] Gjorčeva, V.: Optimization of Processes in Insurance

Company in Order of Operational Costs Reduction,

Master Theisis (in Macedonian language), Faculty of

Mechanical Engineering, UKIM, Skopje, July 2019.

,

https://www.themanager.org/%20Strategy/Procedures_3_Sales.htm

https://www.themanager.org/%20Strategy/Procedures_3_Sales.htm




Received: May 21, 2019 UDC: 334.724:005.334]:001.891.7(497.7)



MANAGING ORGANIZATIONAL CHANGE IN COMMUNAL PUBLIC ENTERPRISES:

A LITERATURE REVIEW

Georgi Hristov1, Gligorče Vrtanoski2




[email protected]

A b s t r a c t: This work presents a literature review regarding the organizational change. The resistance to change

– a “natural associate” on change – was not considered as a separate topic under the scope of this work. More than

thirty academic articles were reviewed and analyzed. An effort was done to link, to confront and, whenever possible,

to compare the different findings about the organizational change as found by the academic research. In general, the

review focuses on the organizational change literature and, in particular, the available peer reviewed academic articles

that focus on the organizational change in public sector. The influence of different factors and behaviours (employees’

participation and commitment, the change context, the management and leadership support, timing, communication

and strategic change process) over the change process was examined. Some models for implementation the change

process and the revolutionary change are mentioned. The concept of changing “whole system” is also mentioned as an

important one when speaking about the change in public sector. The lack of research regarding the organizational

change in communal public enterprises is noted and suggestions for further research are given.

Key words: change process; organizational change; communal public enterprise

УПРАВУВАЊЕ СО ОРГАНИЗАЦИСКИТЕ ПРОМЕНИ ВО КОМУНАЛНИТЕ

ПРЕТПРИЈАТИЈА: ПРЕГЛЕД НА ЛИТЕРАТУРАТА

А п с т р а к т: Трудот дава преглед на литературата во врска со организациските промени. Oтпор кон

промените, што природно го следи нивното воведување, не беше посебно анализиран. Анализирајќи над 30-

ина академски и научни трудови, беше направен обид да се поврзат, спротистават и, секогаш кога е можно, да

се споредат различните научни сознанија за организациските промени. Општо земено, прегледот се фокусира

на литературата за организациските промени со посебен акцент на научните трудови кои се однесуваат на

јавниот сектор. Трудот го проучува влијанието на различните фактори (учеството на вработените и нивната

посветеност, контекстот на промените, управувањето и поддршката од раководството, времето, комуникација-

та и процесот на стратешки промени) во текот на процесот на промена. Споменати се некои модели за импле-

ментација на процесот на промени и радикални промени се споменати. Концептот за промена на „целиот сис-

тем“ е спомнат како клучен во случај на промени во јавниот сектор. Нотиран е недоволниот број истражувања

на организациските промени во комуналните јавни претпријатија се нотирани и се дадени предлози за поната-

мошни истражувања.

Клучни зборови: процес на промена; организациски промени; комунално јавно претпријатие

1. INTRODUCTION

Provision of potable water in the Republic of N.

Macedonia is responsibility of municipalities which

establish utility companies named as Communal

Public Enterprises (CPEs). The term “public” refers

that the government (local or central) owns the util-

ity and that the goods or services are provided in a


66 G. Hristov, G. Vrtanoski

Mech. Eng. Sci. J., 37 (1–2), 65–70 (2019)

monopolistic market. Since the collapse of com-

munism in late 80’s, the planned economy has been

replaced by market economy and most of state-

owned companies have been privatized. However,

the water utility companies are still operating, or

better to say “surviving” as public enterprises. De-

centralization process transferred many responsibil-

ities for delivery of public services from central

governmental level to municipalities, but it has not

been followed with suficient funds to develop the

sector adequately. Thus, the current situation at

CPEs can be characterized as a critical one due to:

poor operational and financial performance, long

debt collection period, over employment, outdated

IT and other equipment [1, 2]. Additionally, even

day-to-day operations seem to be highly influenced

by political interests. In short, the current operations

of the CPEs, still carrying much legacy of the for-

mer system, are not sustainable anymore and could

harm and potentially destroy the water supply sys-

tems in operation. An intensive debate about differ-

ent possible forms of CPEs’ transformation, like

privatization, concession, build-operate-transfer

(BOT), public-private partnership (PPP), outsourc-

ing, contracting etc., which might replace the exist-

ing (unsustainable) way of service delivery is ongo-

ing. Whatever form is decided, and eventually ap-

plied, the changes are inevitable in the CPEs.

The publication “Introduction to Outsourcing

and EU Water Sector Review” authored by the Asso-

ciation of Communal Service Providers (ADKOM)

urged for an immediate action to improve (1) finan-

cial liquidity, (2) maintenance of the water supply

networks and (3) capital investments [3]. Addition-

ally, it showed that both, the politically appointed

managers and employees agreed that “something”

must be changed. Therefore, the municipalities face

the challenges to find solutions for immediate im-

provement in the sector. Some have called for “rad-

ical” changes, too. In such a case, the universally

accepted maxim that “people resist change” might

not be true, at least verbally. This supportive envi-

ronment toward change is in line with findings that

individual resistance is quite rare [4]. Instead, it is

suggested that obstacles to change more often reside

in the organization's structure or in its performance

appraisal or compensation system. This observation

shifts the attention from individuals to the greater

organizational system within which the change is

occurring [5]. Also, the change outcomes are

stronger when perceived need for change is high

than when it is low [6], thus one can assume that

current environment is supportive to introducing

change process in communal public enterprisies.

Therefore, this article aims to provide literature re-

view about the organizational change in the public

utility sector. Eventually, it can serve the managers

as a guide to the available academic findings on this

topic to better prepare themselves, the enterprises

and employees for a coming change process, but

also to the asset owners as well as to customers.

Literature review of some academic research

regarding the organizational change as found in

the public enterprises is given in Section 2. It be-

gins with some pioneering “classics” articles re-

garding the change and continues with the particular

research and findings that address public enter-

prises. Section 3 gives short overview of Macedo-

nian communal sector and assess possibilities for

practical utilization of organizational change. Fi-

nally, the conclusion and recommendations for fu-

ture research are given in Section 4.

2. LITERATURE REVIEW

a) Organizational change

Change is a part of life. In business context,

particularly in recent years, as companies face in-

creased competition, globalization, increased use of

information and communication technologies, re-

cession and at the same time search for excellence

(or survival), changes are inevitably tied with the or-

ganizations [7]. Thus, managing change has at-

tracted many researchers becoming a popular topic

in the wider framework of social change [8] as well

as in the organizational and management literature.

Kurt Lewin – the “father” of the term resistance to

change [9], – suggests a change-implementation

process of unfreezing, moving (change) and refreez-

ing. Relaying on Lewin’s theory, Coch and Franch

published the first known reference [10] on re-

sistance to change concluding that groups which

participate in the design and development of the

changes have much lower resistance than those that

do not. Furthermore, they advise managers to hold

meetings, communicate the need for change and en-

courage employees’ participation in change plan-

ning. Later, it has been noted that the Coch and

Franch’s research is actually about the participation,

not about the resistance [9, 11].

Recently, many authors [12, 6] recommend

employees’ participation as a strong tool for suc-

cessful change process. But, others have challenged

this finding as well. For instance, even long ago

[11], additional criticism of the Coch and French’s

Managing organizational change in communal public enterprises: A literature review 67

Маш. инж.науч. спис., 37 (1–2), 65–70 (2019)

study regarding the concept of participation has

been expressed. In this sense, the Lawrence’s study

symbolizes a first effort to escape from dominant

thinking that participation as a magic panacea for

every change misfortune. Kotter and Schlensiger

were among the first who claimed that organizations

and individuals need to change continually [4]. Uti-

lizing the contingency approach, they suggested that

one must consider the context in which the changes

occur as well. This is in line with findings suggest-

ing that organizational change is difficult to separate

from the context of the business it is in [13]. There-

fore, it is essential to have a thorough understanding

of the organization and its people, as well as of the

change and its consequences. Refference [12]

agrees that the analysis of the context with the

choice of a contingent strategy, question the idea

that participation and involvement are the recipe for

any change process.

Similarly to Lewin, but for the level of an or-

ganization, [14] distinguishes three stages in the or-

ganizational change process – idea generation,

adoption and implementation. It distinguished be-

tween organizations that promote and those that

resist change. In addition, [15] indicated that or-

ganizational change usually engages changes at

three levels: individual, structures and systems, and

climate (interpersonal style). Therefore, an individ-

ual’s response to change depends not only on her/his

personal characteristics, but also on the type of or-

ganization, the existing climate and culture. In this

line, the mechanistic organizations (strong hierar-

chical structure, well defined job descriptions, au-

thority and power based on seniority and experi-

ence) are far worse at managing and coping with

change than organic organizations (flat structure,

flexible job descriptions, weaker authority and pro-

cedures) [12]. Other contribution how organization

can support employees in case of revolutionary

change and to assess whether actions taken depend

on various contextual criteria, is presented in [7].

The authors found that when “behaviours that are

supportive of revolutionary change are undertaken

… there can be a positive impact on critical out-

come variables. Conversely, when behaviours per-

ceived as non-supportive are undertaken … there

can be a decidedly negative impact on both the or-

ganization and the employee” (p.197).

Other important determinant which influences

change is time. Many behavioural scholars, busi-

ness executives and management gurus agree that

timing is one of the most important elements in

planning, delivering, implementing and managing

change [12]. Intentionally or not, most of the

changes are planned and implemented during crisis.

Some authors [16] consider it to be THE crucial var-

iable. Even more, others claim that individual reac-

tions are subject to modifications over time [12].

Communication is other important determi-

nant influencing the implementation of change. The

research literature points that communication is

positively related with an effective change process

[17]. Reference [6] contributed to change theory by

addressing the knowledge gap related to participa-

tion in strategic change. The findings suggest that,

generally, the use of participation seems to be

strongly related to successful implementation of

strategic change, particularly in case when a com-

pany faces the “survival threat”. Also, it was con-

firmed again that “employees' perceptions of the or-

ganization's need for change interact with the use of

participation, making the participation-outcome

links stronger when perceived need for change is

high than when it is low” (p.210).

Refference [6] proposes a 12-step model for

change implementation. The model is based on

three previous well-known change models, i.e.

Kotter’s 8-step model [18], Jick’s 10-step model

[19] and 7-step change acceleration process used at

General Electric which follows notion of unfreez-

ing, moving and refreezing [9]. While Kotter points

out that “skipping any step creates only an illusion

of speed with the consequence of no satisfying re-

sults” [18], in addition, it has been suggested that

all 12 steps are not to be regarded only sequentially,

but also as an integrated, iterative process to enable

change [20]. But, do these criteria of strictly follow-

ing the steps in a change process allow for flexibility

regarding the organizational context? No, they do

not. The reference [21] advises that any organiza-

tional context requires different change strategies

and tools. Even more, they argue that if various

change initiatives are not priority on top manage-

ment agenda, if leadership is not seen as a vital com-

ponent to successful implementation of change ini-

tiatives, then it is hard to accept that such an organ-

ization has committed itself to organizational

change regardless of the model it has chosen.

Although it is generally accepted that em-

ployee commitment plays prominent role in the im-

plementation change models, only recently a model

on commitment to organizational change initiatives

that could serve as guide towards systematic future

investigation has been developed [22]. The model

suggests that commitment could take different

forms and have different implications on the nature


Mech. Eng. Sci. J., 37 (1–2), 65–70 (2019)

and level of employees’ behavioural support for a

change. The further research [23] replicates and ex-

tends this model using samples from different

change contexts. The fact that the obtained results

are similar, provides for a proven evidence about

generalization of the model proposed at [22]. In ad-

dition, refference [23] extended the previous find-

ings by examining relations between commitment

and behavioural support for change (1) over time

and (2) in a non-western societal culture. Actually,

the findings obtained with a sample of Indian man-

agers were very similar to those obtained in [22]

with Canadian nurses. Finally, the findings regard-

ing the relations between commitment and support

for organizational change are consistent with the

claim that employee commitment is a key to the suc-

cessful implementation of organizational change,

but even more, they conclude that commitment to

change is more important than commitment to the

organization.

b) Organizational change in public utilities

The changes in public sector in most Western

economies have been mainly inspired by increased

demand for greater financial accountability, effi-

ciency and effectiveness [24]. Others have found

different reasons for initiating changes. For exam-

ple, the reasons for initiating changes in public sec-

tor is to exhibit many features of the private sector,

including some scope for entrepreneurial behaviour

[25]. Reffernce [26] connects it with the need to deal

with turbulent environments and shifting public sec-

tor towards greater competition by applying private-

sector management style in public domain. Some

public organizations used the Lewin’s three-step

model while others have adopted business process

re-engineering [27]. Some authors argue that what-

ever model is implemented, the progress can be

achieved only if a transformation team is appointed

which has been given authority for change and in-

ternal power [28].

Many authors (e.g. [26 – 28]) agree about deep

differences between public sector organizations and

private companies when it comes to implementation

of the organizational change. Some argue that gov-

ernments have no alternative, but to utilize different

market-based business-oriented reform in the public

sector [29]. Contrary, others [30] argue that trans-

ferring change concepts and approaches from pri-

vate to public sector can lead to contradictory re-

sults. From current perspective, the later findings

seem to be the correct ones. This means that the con-

cepts and approaches to organizational change in

public sector should be accommodated to public

context, which not necessarily has the same motive

to introduce and implement change as private sec-

tor. This is supported by other authors [31] about

what a “changed” public organization is expected to

perform: enact new relationships and partnerships;

think and act strategically; network with other agen-

cies; manage resources effectively; redefine bound-

aries of systems and govern for accountability and

transparency. In short, this type of change is differ-

ent from other forms of organizational change as it

involves the “whole system” approach – getting the

widest representation in the room and that all stake-

holders would try to improve the “whole system” at

the same time [31].

3. ORGANIZATIONAL CHANGE

IN MACEDONIAN’S CPEs

Public enterprise is a form of government in

business. It is expected to achieve economic and op-

erational efficiency, and at the same time serve so-

cial or policy objectives and be accountable to the

public. The reality in Republic of North Macedonia

is that CPEs’ assets are significantly depreciated

and, in general, employees are old, poorly educated

and not-motivated. Although over employment is

evident, there are still pressures for additional new

politically motivated employments. In addition, be-

sides the awareness of need for change (and sur-

vive), there is an emphasized resistance to change

due to fear of losing jobs, IT frustration, loosing po-

litical influence etc. As previously mentioned, there

is on-going debate in the country about the urgent

necessity of transforming (changing) the CPEs. The

debate is mainly focused about what changes are to

be implemented which will provide for companies’

sustainability, improved service level delivery and

increased customer satisfaction leading to increased

performance and cheaper services eventually. The

proposals fall in a continuum from full privatization,

at one side, to keeping the public form, at the other

side.

Practical examples of different management

forms already exist over the world. For example, in

Canada, water and sewage utilities are publicly

owned and operated. In France, many municipali-

ties contract out water and sewage operations to pri-

vate companies. England and Wales have fully pri-

vatized their water and sewage services. Anyway,

the main goal to be achieved is affording an efficient

company that will provide quality service delivery

at reasonable prices. Regarding the efficiency, some

Managing organizational change in communal public enterprises: A literature review 69

Маш. инж.науч. спис., 37 (1–2), 65–70 (2019)

authors claim that there are several reasons to be-

lieve that public enterprises will be less efficient that

private enterprises producing the same product [32].

They mainly relay on the studies reviewed [33]

which offer quite convincing evidence that private

firms are more efficient than public enterprises,

even in different country settings and industries. For

example, for water utilities, it was found that private

firms are more efficient than public firms by

amounts ranging from 15% to 40%. Very contrary

to these findings, others argue against privatization

of CPEs as a possible change model for increasing

efficiency [34]. They claim that CPEs appear no less

efficient than privatized ones. Some of their argu-

ments against are “that privatization carries signif-

icant risks in water and sanitation, given the nature

of the service as a natural monopoly, the de facto

lack of competition on an international scale, the

difficulty of regulating multinational companies, es-

pecially in transition and developing countries, the

potentially high economic and social costs of mo-

nopolistic behaviour by commercial operators” [34,

p. 52]. Even more, they provide evidence that public

water supply sector in transition and developing

countries is as affordable as the developed coun-

tries.

A snapshot on the current efficiency of the al-

ready privatized Macedonian companies in other

sectors is in line with above Lobina and Hall’s find-

ings. Namely, the evidence showed that the effi-

ciency of the privatized companies has not in-

creased as expected, although, the profitability does.

The increased profitability satisfies an owner’s in-

terest only, however, on the costs of lower invest-

ments and capacity development. Very probably,

weak regulatory and institutional mechanisms to

control financial operations of private companies

and lacking expertise in regulating public (particu-

larly water supply services), might be enough argu-

ments towards keeping public form of communal

services delivery. However, this shall not prevent

introducing change processes in the public enter-

prises’ operations. It is only suggested that privati-

zation might not be the magic panacea for solving

the operation and financial inefficiency of public

communal enterprises in Republic of North Mace-

donia.

Clearly, changes are necessary and urgent. The

employees and management of Macedonian public

companies are convinced in the need of change and,

at least, verbally are supportive. However, the ru-

mours against the change are already spread around.

The issue of rumours is not a new one and it is al-

ready well addressed by organizational change and

resistance to change literature. Three main reasons

[35] are revealed for organizational resistance to

change: technical barriers (habit and inertia), politi-

cal reasons (threats to coalitions may signal leader-

ship problems), and cultural reasons (lack of a cli-

mate’s support of change, regressing to “old days”

of operations). All three reasons perfectly fit in the

current real situation with the political and cultural

ones having probably the biggest influence in the

Republic of North Macedonia. It is also important

to note that the CPEs carry a huge legacy system and

company’s history of “status quo” and such enter-

prises which have not practiced changes before can-

not carry out the change successfully [12].

4. CONCLUSION

The paper provided some insights of the basic

organizational change factors with focus on public

sector. Based on the literature reviewed it is obvious

that public sector faces more challenges than private

with managing the organizational change process.

Many water supply utilities from Central and East-

ern Europe experience the process of transformation

in the last twenty years, however, on the other side,

there is still lack of research regarding the change in

public enterprises (e.g. [34 – 21]). Therefore, it is

suggested for more research on the topic in the sec-

tor in order to fill-in the existing gap between the

accumulated knowledge and theory about organiza-

tional change, in general, and the CPE’s change, in

particular. It is also advised to test the existing find-

ings regarding the participation, communication,

commitment, management and leadership support,

etc. in public utility sector in Central and Eastern

Europe.

Such future research should focus on contex-

tual factors within the public enterprises bearing on

mind the legacy they carry as well as political influ-

ence. In this regard, attention must be paid on dif-

ferent cultural settings, company’s history and the

customers. This “whole system” approach should be

verified under such settings, as customers are an im-

portant stakeholder in public sector operations. This

will enable to reveal the reasons and factors prevent-

ing public companies to achieve the required im-

provements when introducing change process,

something what is well noted in [21].

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Received: May 18, 2019 UDC: 004.896:531.17]:007.52-025.42

Accepted: May 25, 2019


KINEMATIC MODELLING AND ANALYSIS OF SERIAL MANIPULATOR

Simona Domazetovska, Hristijan Mickoski, Marjan Djidrov

Faculty of Mechanical Engineering, "Ss. Cyril and Methodius" University in Skopje,

Karpoš II bb, P.O. box 464, 1001 Skopje, Republic of North Macedonia

[email protected]

A b s t r a c t: The purpose of this paper is modelling and simulation of serial manipulator type with four rotating

joints (RRRR). CAD model was developed by using the software SolidWorks for modelling the serial manipulator.

Simulation model of serial robot is made by conversion from SolidWorks to Matlab/Simulink. The serial robot can be

shown schematic as a kinematic connection of rigid bodies that are interconnected using rotary kinematic pairs. The

manipulator movement is defined so the movement of each member is related to the previous one. The position and

orientation of the gripper must be defined to ensure safe handling. In this paper, the steps needed to model the serial

manipulator together with all its components, its transfer into Simulink and its Proportional Integral Derivative (PID)

controlling and simulation is described. The obtained results for velocity and acceleration in kinematic pairs contribute

in detailed analysis of kinematics and control design.

Key words: serial robots; serial robot kinematics; manipulator; PID control

КИНЕМАТСКО МОДЕЛИРАЊЕ И АНАЛИЗА НА СЕРИСКИ МАНИПУЛАТОР

А п с т р а к т: Целта на овој труд е моделирање и симулација на сериски робот со четири ротирачки

зглобови (РРРР). Моделот CAD е изработен во програмскиот пакет SolidWorks со цел моделирање сериски

робот. Извршена е симулација во програмскиот пакет Matlab/Simulink. Имитационен модел на сериски робот е

добиен со префрлање на моделот од SolidWorks во програмскиот пакет Matlab/Simulink. Серискиот робот може

да биде анализиран како кинематска врска на крути тела кои меѓусебно се поврзани со ротирни или кинематски

парови. Движењето на роботот се дефинира така што се дефинираат движењата на секој член во однос на

претходниот. За да се обезбеди сигурна манипулација во просторот, потребно е да се дефинира положбата и

ориентацијата на фаќачот. Во овој труд целосно се дефинирани и опишани сите чекори потребни за моделира-

ње на овој робот заедно со сите негови составни делови, негово префрлање во програмскиот пакет Мatlab/

Simulink и управување преку пропорционална потполнo деривирана (изведена) контрола (PID-контрола) и

симулација. Добиените резултати за брзините и забрзувањата во неговите кинематски врски служат за детална

анализа на кинематиката и контрола на движењето.

Клучни зборови: сериски робот; кинематика на сериски робот; манипулатор; PID-контрола

1. INTRODUCTION

Computer modelling, simulation and imple-

mentation tools have been widely used to support

and develop nonlinear control, robotics, and MAT-

LAB/SIMULINK courses. MATLAB with its tool-

boxes such as SIMULINK [1] is one of the most

accepted software packages used by researchers to

enhance teaching the transient and steady-state

characteristics of control and robotic courses [2].

The international organization defines the

robot as an automatically controlled, reprogram-

mable, multipurpose manipulator with three or more

axes. Robot manipulator is a collection of links that

connect to each other by joints, these joints can be

revolute and prismatic that revolute joint has rotary

motion around an axis and prismatic joint has linear

motion around an axis [3]. Each joint provides one

or more degrees of freedom (DOF). From the

mechanical point of view, robot manipulator is


72 S.. Domazetovska, H. Mickoski, M. Djidrov

Mech. Eng. Sci. J., 37 (1–2), 71–77 (2019)

divided into two main groups, which called; serial

robot links and parallel robot links. In serial robot

manipulator, links and joints is serially connected

between base and final frame (end-effector).

Most of industrial robots are serial links and

can be used as surgical robot and space robot mani-

pulator.

Kinematics is an important subject to find the

relationship between rigid bodies and end-effector

in robot manipulator. Kinematic modelling of ro-

bots benefits the industrial automation processes by

making them semi-autonomous or even fully auto-

nomous. Because of the task nature and operational

environment, the industrial robots are usually com-

posed up of series of rigid links mounted on a base.

A 6-Degree оf Freedom (DOF) robotic arm mani-

pulator is widely used in the industry. The most

common applications of industrial robots include

Spot welding, Spraying, Assembling and Manufac-

turing. Many of these applications actually require

accomplishment of pick and place task. Implemen-

tation of this task fundamentally requires having the

kinematic model of the robotic arm being active.

The forward kinematic model predicated on

Denavit Hartenberg (DH) parametric scheme of

serial robot arm position placement using Robotics

toolbox is analyzed by the researchers in [4]. Given

the desired position and orientation of the robot end-

effector, the realized kinematics model provides the

required corresponding joint angles. In the area of

robot modelling and simulation, kinematics is a

widely researched topic. The robot modelling and

analysis techniques are typically based on line trans-

formation or on point transformation. Clothier et al.

[5] proposed a geometric model to solve the un-

known joint angles required for autonomous positi-

oning of a robotic system. In [6] is presented a

method for forces and moments determination in

kinematic joints of a three-member manipulator

analytically by using the Lagrangian second-order

equation and the principle of virtual work. Sahu et

al. [7] derived a new method, quaternion algebra,

for solution of forward kinematic problem. Popovic

et al. [8] developed a strategy to analyze the upper

extremity movement of the arm, while complete

Wang et al. [9] presented body kinematics of a

radial symmetrical six legged robot. Kinematic ana-

lysis of a new type of hybrid (parallel–serial) robot

manipulator, consisting of two serially connected

parallel mechanisms were analyzed in [10].

A method for solving the complete dynamic

problem in serial robots with rigid links and ideal

joints using the Gibbs-Appell equations as starting

point is presented in [11].

The researchers in [12] present a new formu-

lation method to solve kinematic problem of serial

robot manipulators, aiming to formulize inverse

kinematic problem in a compact closed form to

avoid singularity problem. The main targets in de-

signing control systems are stability, good distur-

bance rejection, and small tracking error [13]. Seve-

ral industrial robot manipulators are controlled by

linear methodologies [e.g. Proportional Derivative

(PD) controller, Proportional Integral (PI) controller

or Proportional Integral Derivative (PID) control-

ler].

Modelling and simulation of serial manipu-

lator, type RRRR (rotation, rotation, rotation, rota-

tion) will be analyzed in this work. For this purpose,

CAD modelling in Solid Works and modelling and

simulation of the behaviour of the serial manipu-

lator in Matlab/Simulink will be analyzed. PID

control will be applied to the manipulator in order

to control the robot.

2. MODELLING OF THE SERIAL ROBOT

IN SOLID WORKS

Modelling of different systems is a process of

creating appropriate model of the analyzed system

thus, all the necessary research and teaching of the

system can be performed on the model, rather than

on a real system. The process of modelling systems

is important stage while researching in terms of

reducing the time and resources. The simulation is

not a method to make an optimal solution, but pro-

vides an opportunity to evaluate the quality of the

system relative to another.

Modelling of the parts and their kinematic

pairs was analyzed in SolidWorks. In order to

understand and develop the properties of serial

robots, a model of a serial manipulator (Figure 1)

was developed and based on this model direct

kinematics is presented.

As it can be seen from Figure 1, the serial robot

has a functional and a simple structure. The model

is consisted of six individual parts that are con-

nected through kinematic pairs, creating a compact

structure of serial manipulator. The components of

which the robot is consisted are:

– base, which is attached to the work surface,

– rotational joints which allows one degree rota-

tion of the robot,

– connection part, that enables the second rota-

tion of the robot and has a larger dimension,

so it can allow larger working space,

Kinematic modelling and analysis of serial manipulator 73

Маш. инж. науч. спис., 37 (1–2). 71–77 (2019)

– cylindrical part that allows the third rotation

of the manipulator. It has a cylindrical recess

which enables translation of the connected

kinematic pair,

– piston section, which enables increasing of the

working space,

– gripper, the executive member, located at the

end of the robot’s structure in order to perform

the certain mission.

Fig. 1. Structure of the serial robot modelled in Solid Works

Due to the greater stability required to ensure

high accuracy of the gripper, four support parts are

placed at an angle of 90° to eachother. The robots

control interface is attached on the base consisted of

electronics. The material and dimension of the base

are chosen according to the required performance.

The rotary part is composed of a cylinder that

has the same dimensions as the cylindrical opening

of the base. Using the mate tool, the rotary part is

connected with the base. The robustness and relia-

bility of the serial manipulator while increasing the

working space are one of the things that have to be

considered while modelling.

The cylindrical part is consisted of two mutu-

ally normal cylindrical openings. The opening of the

cylinder part is intended to form a piston mecha-

nism, whose main achievement is to increase the

robot’s working space. The piston part is composed

of a cylinder, a circular heat for limitation of the

movement and holder for the gripper. The gripper is

the last link from the serial robot, which structure is

shown on Figure 2.

All of the previous parts actually serve to posi-

tion the gripper to the required location of perfor-

mance. The gripper is the most complex part of the

serial manipulator, composed of many parts that

form one functional structure. The structure allows

performing movements of the gripper through

cylindrical axis located in the middle, hydraulic

driven. The movement of the gripper is transferred

through the mechanisms.

Fig. 2. CAD model of the gripper

Figure 3 shows a schematic representation of

the serial robot, showing all of its parts along with

the provided manoeuvres. The workspace is rela-

tively high, allowing the gripper manipulating away

from the base with great accuracy.

Fig. 3. Schematic representation of the serial manipulator

2.1. Direct kinematics modelling

Denavit-Hartenberg’s method is an efficient

procedure for the determination of direct kine-

matics, widely used in robotic applications. In order

to calculate the direct kinematic equations for an

open chain manipulator, it is necessary to derive and

define a relative position and orientation of two

consecutive links. While solving the kinematics of

the links, relationship between the two parts has to

be defined.


Mech. Eng. Sci. J., 37 (1–2), 71–77 (2019)

The axis 𝑖 is defined for the connections of the

parts 𝑖 − 1 and 𝑖 .The axis of the joint 𝑖 + 1 is

chosen, and the point Oi is located between the inter-

section of the zi axis with the normal segment to the

zi–1 and zi axes. Axis xi is defined which has the same

direction as the drawn segment and at the same time

is normal on the z-axis. In order to complete the

coordinate systems, axis yi is selected.

Once the kinematic parameters are defined, the

transformation between the 𝑖 − 1 and 𝑖 coordinate

systems can be expressed.

The homogeneous transformation matrix for

the chosen system in the selected coordinate system

will be:

𝐴𝑖𝑖−1 (

cos(𝜃𝑖) −sin(𝜃𝑖) 0 0sin(𝜃𝑖) cos(𝜃𝑖) 0 0

0 0 1 𝑑𝑖

0 0 0 1

) (1)

If the selected system is moved from its

position along the x-axis, the position is rotated for

angle αi along the x-axis. The new position will

match with the new position of the coordinate

system i. Its homogeneous transformation matrix

will be:

𝐴𝑖𝑖′

(

1 0 0 𝛼𝑖

0 cos(𝛼𝑖) −sin(𝛼𝑖) 00 sin(𝛼𝑖) cos(𝛼𝑖) 00 0 0 1

) (2)

The resulting transformation of the coordinate system is obtained by multiplying the individual

homogeneous transformations:

𝐴𝑖𝑖−1(𝑞𝑖) = 𝐴𝑖

𝑖−1𝐴𝑖𝑖′

(

cos(𝛳𝑖) −sin(𝛳𝑖)cos(𝛼𝑖) sin(𝛳𝑖)sin(𝛼𝑖) 𝛼𝑖cos(𝛳𝑖)sin(𝛳𝑖) cos(𝛳𝑖)cos(𝛼𝑖) −cos(𝛳𝑖)sin(𝛼𝑖) 𝛼𝑖sin(𝛳𝑖)

0 sin(𝛼𝑖) cos(𝛼𝑖) 𝑑𝑖

0 0 0 1

) (3)

The Denavit-Hartenberg method allows the

definition of kinematic functions by combining

individual homogeneous transformations into a

resultant transformational matrix. This procedure

can be applied to any open kinematic chain.

3. ANALYTICAL MODELLING OF SERIAL

ROBOT

The behaviour of physical systems in many

situations may better be expressed with an analy-

tical model. Modelling a robot involves study of its

kinematic behaviour. A kinematic model is con-

cerned with the robot’s motion without considering

forces producing the motions. The Simulink pro-

gramming package is part of Matlab and has a great

application in the technique and serves for mode-

lling, simulation and analysis of dynamic systems in

multiple areas. It can work with non-linear and

linear systems in discrete and continuous time and

explore the impact in the real models, which are real

phenomena and affect the real model. Simulink uses

a block library that, with a simple drag-and-drop

procedure, ships into a separate window for a model

and with appropriate blocking of the blocks, a

model is created that can be easily repaired and

updated later on. It is connected to the Matlab tools

and has instant access to them, so Simulink models

can be easily analyzed and visualized. Once the

Solid Works model is developed, in order to

perform a simulation, it should be transferred to

Matlab/Simulink which is enabled automatically by

the Multibody tool provided by MathWorks. The

basic criteria needed to be established are: the prog-

ram compatibility, installation files, connectivity,

solid model support and model export. The Matlab/

Simulink model of the serial robot is shown on

Figure 4.

The simulation of the gripper is created as an

imitation model independent of the previous one,

modelled due to its functionality in Matlab. The

controlling of the gripper is performed due to the

geometry of the two parts of the gripper, rotated for

450, in order to achieve closing of the gripper.

Figure 5 shows the visual look and the Simulink

model of the gripper.


Маш. инж. науч. спис., 37 (1–2). 71–77 (2019)

Fig. 4. Matlab/Simulink model of the serial robot

Fig. 5. Matlab/Simulink model of the gripper

4. PID CONTROL

PID (Proportional Integral Derivative) con-

trollers use a control loop feedback mechanism to

control process variables and are the most accurate

and stable controller. PID integral differential meth-

od is the expansion of simpler PD management.

Enlargement is done by adding an integral compo-

nent. Adding this component substantially reduces

the positional error in the joints of and it is approxi-

mate to zero.The PID law is represented by the

following equation:

u(t) = 𝐾𝑝𝑒(𝑡) + 𝐾𝑖 ∫ 𝑒(𝑡)𝑡

0𝑑𝑡 + 𝐾𝑑

𝑑𝑒(𝑡)

𝑑𝑡 (4)

where 𝐾𝑝 is a proportional amplifier, Kd is a differ-

rential amplifier and Ki is a integration amplifier.

The connection of the PID controller to Simul-

ink simulated models is very useful and effective.

Since the wanted motion is initiated in kinematic

pairs, the actuator block is linked to the kinematic

link between two rigid bodies. In order to have

control accuracy data, a kinematic relationship

sensor is set which measures displacements, velo-

city and acceleration. To assign a value to the mana-

gement, a step function is used which is passed thro-

ugh one slider and will have values from −100° ÷ 130 °, and it can be real-time during the simulation

to change and in that way to perform planned cont-

rol in real time.The sum of the two values is dedu-

cted by the return function representing the error

and thus controlling the accuracy of the entire sys-

tem. The controlling of the system in Matlab/Simu-

link is shown on Figure 6.

Individual PID controllers can operate inde-

pendently in relation to each other and this is their

great advantage. It is possible to generate a force in

a kinematic pair and thus move one part of the robot,

while the previous parts remain stationary.


Mech. Eng. Sci. J., 37 (1–2), 71–77 (2019)

Fig. 6. PID control of the serial manipulator

5. RESULTS

The velocity and acceleration of each of the

kinematic pairs are analyzed. The results of the

measured data are shown on a graph for each

kinematic pair separately. The serial robot requires

fivesuch structures that are placed in the model and

tested. The results for the five parts are shown on

Figure 7.

After applying control on the manipulator’s

gripper, the results for the velocity and acceleration

are analyzed, shown on Figure 8.

Fig. 7. Velocity and acceleration results for each of the kinematic pairs

Fig. 8. Velocity and acceleration – results for the gripper

6. CONCLUSION

Modelling and simulation of robotic systems

using various software reflects the process of de-

signing, constructing and controlling robots in the

real world. Simulating the dynamic processes pro-

vides an overview of the behaviour of the existing

dynamic system with proper management. Simula-

tion is of great importance because with it the cons-

tructors can presume and evaluate the behaviour of

the robot, as well as to confirm and optimize the

robot movement plan for the given problem. The

simulation significantly reduces the time and costs


Маш. инж. науч. спис., 37 (1–2). 71–77 (2019)

that are unavoidable in experimental research of

dynamic systems, and plays an important role in the

evaluation of production.

The presented serial robot manipulator has

been kinematically modelled followed by the ana-

lysis of its workspace and for the modelling of the

robot SolidWorks and Matlab softwares were used.

Forward kinematic model has been validated by

using Matlab and PID controlling was used to con-

trol the serial robot manipulator.

The possibility of simulation opens up a wide

range of opportunities for creative solving of many

problems. Serial manipulators are more and more

used in industry, and in environments that are inac-

cessible or risky for humans. Their simple structure

made up of rotary and translator kinematic pairs

allows the executive member to easily position and

orient in the workspace. They work with great accu-

racy and speed, in places that require great precision

and responsiveness.

REFERENCES

[1] Kurfess, T. R.: Robotics and Automation Handbook. CRC

Press, 2004.

[2] Ogata, K.: Modern Control Engineering (pp. 6142–6143).

Upper Saddle River, NJ, Prentice Hall, 2009.

[3] Piltan, F., Emamzadeh, S., Hivand, Z., Shahriyari, F.,

Mirazaei, M.: PUMA-560 robot manipulator position

sliding mode control methods using MATLAB/SIMU-

LINK and their integration into graduate/undergraduate

nonlinear control, robotics and MATLAB courses. Inter-

national Journal of Robotics and Automation, 3 (3), 106–

150 (2012).

[4] Iqbal, J., Islam, R. U., Khan, H.: Modelling and analysis of

a 6 DOF robotic arm manipulator. Canadian Journal on

Electrical and Electronics Engineering, 3 (6), 300–306

(2012).

[5] Clothier, K. E., Shang, Y.: A geometric approach for

robotic arm kinematics with hardware design, electrical

design, and implementation. Journal of Robotics, Volume

2010, Article ID 984823, 10 pages,

http://dx.doi.org/10.1155/2010/984823

. [6] Mickoski, H., Mickoski, I., Djidrov, M.: Dynamic

modelling and simulation of three-member robot mani-

pulator. Mathematical Models in Engineering, Vol. 4,

Issue 4, pp. 183–190 (2018).

[7] Sahu, S., Biswal, B. B., Subudhi, B.: A novel method for

representing robot kinematics using quaternion theory,

2008.

[8] Popovic, N., Williams, S., Schmitz-Rode, T., Rau, G.,

Disselhorst-Klug, C.: Robot-based methodology for a

kinematic and kinetic analysis of unconstrained, but

reproducible upper extremity movement. Journal of

Biomechanics, 42 (10), 1570–1573 (2009).

[9] Wang, Z., Ding, X., Rovetta, A., Giusti, A.: Mobility

analysis of the typical gait of a radial symmetrical six-

legged robot. Mechatronics, 21 (7), 1133–1146 (2011).

[10] Tanev, T. K.: Kinematics of a hybrid (parallel–serial) robot

manipulator. Mechanism and Machine Theory, 35 (9),

1183–1196 (2000).

[11] Mata, V., Provenzano, S., Valero, F., Cuadrado, J. I.:

Serial-robot dynamics algorithms for moderately large

numbers of joints. Mechanism and Machine Theory, 37

(8), 739–755 (2002).

[12] Sariyildiz, E., Temeltas, H.. Solution of inverse kinematic

problem for serial robot using dual quaterninons and

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May, pp. 475–480.




Received: November 4, 2018 UDC: 004.896:531.17]:007.52-025.41

Accepted: February 20, 2019


CAD MODELLING OF PARALLEL ROBOT (TRIPOD) IN MATLAB/SIMULINK

Maja Anačkova, Hristijan Mickoski



[email protected]

A b s t r a c t: The purpose of this paper is to create a model simulation of a parallel robot with PID controller

using the programming package Matlab/ Simulink. In this paper, forward and inverse kinematics of parallel robot tripod

is presented; model of the parallel robot in the programming package Solid Works is constructed; simulation model of

the parallel robot tripod is made by conversion from Solid Works to Matlab/Simulink and results for velocities and

accelerations in its kinematic joints are obtained that serve to the management and control of the mobile platform as a

major problem in the construction of a parallel robot. Model simulation of parallel robot will be the basis for creating

models of parallel robots with more complex structure, detailed understanding of their kinematics and control design

as an inevitable part of the future of robotics and mechatronic.

Key words: parallel robots; tripod; parallel robot kinematics; model simulation

CАD-МОДЕЛИРАЊЕ НА ПАРАЛЕЛЕН РОБОТ (ТРИПОД) ВО MATLAB/SIMULINK

А п с т р а к т: Целта на овој труд е креирање на имитационен модел на паралелен робот со пропорцио-

нално целосно деривирано (PID) управување во програмскиот пакет Matlab/ Simulink. Во овој труд е разрабо-

тена директна и инверзна кинемaтика на паралелен робот со три нозе; модел на паралелниот робот е изработен

во софтверскиот пакет Solid Works; имитационен модел на паралелен робот со три нозе е добиен со префрлање

на моделот од Solid Works во програмскиот пакет Матлаб/Симулинк и се добиени резултати за брзините и

забрзувањата во неговите кинематски врски кои служат за управување и контрола на движењето на подвижната

платформа, што е главна задача при конструкција на еден паралелен робот. Симулацијата на модел na парале-

лен робот со три нозе ќе биде основа за креирање на модели на паралелни роботи со многу посложена струк-

тура, детално разбирање на нивната кинематика и управување како неизбежен дел од иднината на роботиката

и мехатрониката.

Клучни зборови: паралелен робот; кинематика на паралелен робот; симулација на модел

1. INTRODUCTION

In the last decades, parallel robots have moti-

vated a great interest because of their characteristics

of small moving masses, preciseness and high-

speed controllability compared to the serial robots.

They have been widely used for the reconfigurable

structure due to their inherent modularity. Such de-

sign and analysis for a reconfigurable parallel robot

is given in [1] and [2]. Generally, parallel robots are

constructed from a fixed, called stationary platform,

a mobile or moving platform and legs which con-

nect these two platforms. This parallel kinematics

have significant advantages over the serial robots

because of their accuracy, rigidness and higher load

capacity. These parallel kinematics machines

(PKMs) have many applications such as from air-

crafts simulators, machining tools, micro-motion

machines [3]. In industrial applications, most

widely used are the parallel robots that generate

spherical rotation around a certain point as shown in

[4].

The problem of kinematics of these parallel

structures means determination of their direct and

inverse kinematics equations. The direct kinematics

explains the motion in terms of a base fixed


80 M. Anačkova, H. Mickoski

Mech. Eng. Sci. J., 37 (1–2), 79–86 (2019)

Cartesian coordinate systems according to which

the position and orientation of the end effector (in

this case the moving platform) are determined. The

inverse kinematics is more complex, it includes

calculation of the possible values for the angular and

linear displacements of the joints in order for the

mobile platform to achieve a certain trajectory or a

desired position [5]. A comparative analysis of these

two methods is presented in [6].

The kinematics and dynamics problems of the

robots in general are solved by using the modelling

and simulation methods in a certain software that

supports this analysis. Most commonly used soft-

ware is Matlab software package, more concisely

Matlab/Simulink which allows this kind of identi-

fication and analysis of the robot parameters in a

virtual environment. It allows real-time simulations

of the motion of the robot showing the changes in

the position, velocity and acceleration of a desired

joint or body [7]. From the simulated model of

parallel manipulator in [8] it can be concluded that

the choice of the generalized coordinate does not

provide a unique determined position on the mobile

platform without taking into account the conditions

of the kinematic joints, linear and the angular velo-

cities. Matlab/Simlunk also allows integrating a

control algorithm and the response of the robot

under the given control. A model of 3-RRR planar

parallel robot controlled by a PID controller in

Matlab/Simulink is explained in [9].

In this paper, a three-legged RRR parallel

robot model in the Solid Works program package-

was developed as given in Section 2. Based on this

model, a simulation of the movement of the mov-

able platform (its trajectory) was later conducted

considering the direct and inverse kinematics ex-

plained in Section 3. Further, PID control was

implemented and graphs of the dynamic parameters

were exported and shown in Section 4 in order to

understand the motion of the movable platform.

2. MODELLING OF THE TRIPOD IN SOLID

WORKS

The kinematic and dynamic analytical study of

different systems (mechanical, electrical, etc.) is

usually done by their modelling and simulation. The

goal of the modelling process of a single system is

to create an adequate, verifying model of the sys-

tem. Thus, all the necessary research and system

studies can be performed on the model instead of a

real system, which saves time and resources.

Modelling is the most important stage in the rese-

arch of a single system. It should lead to a model

that will contain the basic properties of the system

necessary to solve the tasks of the research. The

model should be fully available for the means of

appropriate science and mathematics and to store all

the characteristic elements of the systems output.

Closely related to the modelling process is the

process of simulation. The term simulation refers to

an experimental approach for analyzing and obser-

ving the functional properties of a system using its

simplified model. The simulation of mechanical

systems gives us visualization of the dynamic beha-

viour of the mechanical system. At the core of the

simulation is the verifying model of the system as a

real object for testing. Simulation is not a method to

make an optimal solution, but provides an opportu-

nity to evaluate the quality of the system relative to

another. It represents an experiment performed on

the model. In order to understand and analyze the

properties of parallel robots, a three-legged parallel

robot model was designed in the Solid Works prog-

ram package.

The model of parallel robot consists of a sta-

tionary (bottom) platform, three legs representing

clips that can perform a translatory movement and a

movable (upper) platform (Figure 1). The bottom

platform fixed to the base through the three pairs of

screws and nuts. The joints of the platform's legs are

made by means of rotational connections (Figure 2).

Fig. 1. Model of tripod in “Solid Works”

Fig. 2. Rotational joints between the legs

and the stationary platform

CAD modelling of parallel robot (tripod) in Matlab/Simulink 81

Маш. инж. науч. спис., 37 (1–2), 79–86 (2019)

The lower and upper platforms are flat triang-

les that are identical by their dimensions (Figure 3).

Fig. 3. Platform geometry

Tripod motion is allowed in three degrees of

freedom: translation along the y-axis (top-down)

(Figure 4a), rotation around the y-axis (Figure 4b)

and translation by z-axis (Figure 4c).

Fig. 4. Degrees of freedom of the tripod

Since we have already defined the geometry

and degrees of freedom of this robot, we can easily

obtain the equations for its direct and inverse kine-

matics.

2.1 Direct kinematics

The rotational connections attached to the fix-

ed platform are 𝐴𝑖, while those on the mobile plat-

form are 𝐵𝑖 , where 𝑖 = 1, 2, 3 . Accordingly, the

three feet of the robot will be 𝐴𝑖𝐵𝑖 . The points

𝐴𝑖 and 𝐵𝑖 form a flat triangle with sides 𝑎 and 𝑏

respectively. We specify the lengths of the sides

with 𝑖 = 1, 2, 3 and their slope to the fixed base is

0, i.e. they are placed at right angles to the base

(Figure 5).

Fig. 5. Coordinate systems of the platforms

On the stationary platform, we join the coordi-

nate system Axyz, such that point A is at the center of

the symmetry of the base, the axes x and z lie on the

base, and the y-axis is normal to the stationary

platform. Analogously, the Bxyz coordinate system is

attached on the mobile platform.The positions of the

rotational pairs 𝐴1, 𝐴2, 𝐴3 in the Axyz coordinate

system are:

𝐴1 = (𝑎

2, 0,𝑎

2)𝑇

= (𝐴11,𝐴12,𝐴13,)𝑇,

𝐴2 = (𝑎

2, 0, −

𝑎

2)𝑇= (𝐴21,𝐴22,𝐴23,)

𝑇, (1)

𝐴3 = (−𝑅, 0,0)𝑇 = (𝐴31,𝐴32,𝐴33,)

𝑇.

Similarly, the positions of the rotational pairs

with respect to the Bxyz coordinate system are:

𝐵1 = (𝑏

2, 0,𝑏

2)𝑇

= (𝐵11,𝐵12,𝐵13,)𝑇,

𝐵2 = (𝑏

2, 0, −

𝑏

2)𝑇= (𝐵21,𝐵22,𝐵23,)

𝑇, (2)

𝐵3 = (−𝑟, 0,0)𝑇 = (𝐵31,𝐵32,𝐵33,)

𝑇.

The position of the mobile platform relative to

the stationary platform is determined by the Euler

angles 𝜑1and 𝜑2 and the vector 𝐵 = (0, 𝐵𝑇). The

geometric relationship of the coordinate systems,

that is, the position of the movable coordinate

system relative to the stationary of the lower

platform is described using a 4×4 matrix with

homogeneous transformations:

𝑇 = 𝑇(0, 𝜑1, 𝜑2) =

= [

cos𝜑1 −sin 𝜑1𝑠𝑖��𝜑1cos𝜑2 −cos𝜑1cos𝜑2

0 0𝑠𝑖��𝜑2 0

sin𝜑1 sin𝜑2 −cos𝜑1sin𝜑20 0

cos𝜑2 00 1

] (3)

From the previous equation follows that the

position of the rotational pairs Bi in relation to the

coordinate system Axyz are determined by the vector:

[𝐵𝑖] =

(

[𝐵𝑖,1]

[𝐵𝑖,2]

[𝐵𝑖,3]

1 )

= 𝑇(0, 𝜑1, 𝜑2)

(

[𝐵𝑖,1]

[𝐵𝑖,2]

[𝐵𝑖,3]

1 )

=

= 𝑇(0,𝜑1, 𝜑2)𝐵𝑖 = 𝑇𝐵,


Mech. Eng. Sci. J., 37 (1–2), 79–86 (2019)

[𝐵1] =

(

𝑏

2cos𝜑1

𝑏

2sin𝜑1 cos𝜑2 +

𝑏

2

sin𝜑2

𝑏

2sin𝜑1 sin𝜑2 +

𝑏

2

cos𝜑2

1 )

,

[𝐵2] =

(

𝑏

2cos𝜑1

𝑏

2sin𝜑1 cos𝜑2 −

𝑏

2

sin𝜑2

𝑏

2sin𝜑1 sin𝜑2 +

𝑏

2

cos𝜑2

1 )

, (4)

[𝐵3] = (

−𝑟cos𝜑1−𝑟sin𝜑1 cos𝜑2−𝑟sin𝜑1sin𝜑2

1

).

Consequently, the generalized coordinate 𝑙𝑖 is

calculated according to the following equation:

𝑙𝑖 = 𝑙𝑖(0, 𝜑1, 𝜑2) = √∑(𝐴𝑖,𝑗 − [𝐵𝑖,𝑗])2,

𝑗 = 1, 2, 3 and 𝑖 = 1, 2, 3. (5)

2.2. Inverse kinematics

The rotational pairs are designed on the base

(stationary platform) with A, B and C while they are

on the movable platform with a, b, and c. We repre-

sent the lengths of the legs with the generalized

𝑙1, 𝑙2 and 𝑙3 coordinates:

𝒍𝟏 = (𝑿𝑨𝟏 − 𝑿𝑩𝟏)𝟐+ (𝒀𝑨𝟏 − 𝒀𝑩𝟏)

𝟐+

+ (𝒁𝑨𝟏 − 𝒁𝑩𝟏)𝟐,

𝒍𝟐 = (𝑿𝑨𝟐 − 𝑿𝑩𝟐)𝟐+ (𝒀𝑨𝟐 − 𝒀𝑩𝟐)

𝟐+ (6)

+ (𝒁𝑨𝟐 − 𝒁𝑩𝟐)𝟐,

𝒍𝟑 = (𝑿𝑨𝟑 − 𝑿𝑩𝟑)𝟐+ (𝒀𝑨𝟑 − 𝒀𝑩𝟑)

𝟐+

+ (𝒁𝑨𝟑 − 𝒁𝑩𝟑)𝟐.

3. MODEL SIMULATION IN

MATLAB/SIMULINK

For faster and more efficient problem solving

in the modern practice, advanced software and soft-

ware packages are required. Such program package

is Matlab created from MathWorks and it is a pro-

gramming language for technical calculations

which can also perform visualization and program-

ming. The Simulink programming package is a part

of Matlab software and has a great application in the

modelling, simulation and analysis of dynamic sys-

tems in multiple areas. It is practical, because it can

work with non-linear and linear systems, and can

work in discrete and continuous time. It also can

explore real models, their impact from friction, air

resistance, etc., which are real phenomena and af-

fect the real model. Simulink uses a block library

that, with a simple drag-and-drop procedure, ships

into a separate window for a model and with appro-

priate arranging of the blocks, a model that can be

easily repaired and updated is created. It is connec-

ted to the Matlab tools and has instant access to

them, therefore Simulink models can be easily ana-

lyzed and visualized (Figure 6).

Fig. 6. Block scheme of the tripod in Simulink


Маш. инж. науч. спис., 37 (1–2), 79–86 (2019)

Once the Solid Works model is developed, in

order to perform a simulation it should be

transferred to Matlab/Simulink which is enabled

automatically by the Multibody tool provided by

MathWorks.

The first generation of SimMechanics under

Matlab/Simulink includes a library of blocks and

visualization tools that have been released in Sim-

Mechanics versions before Matlab R2012a. The

latest generation is simpler modelling with a new

library of blocks, with a much more powerful com-

puting machine, more advanced visualization based

on OpenGL® computer graphics, and more detailed

integration between SimscapeTM products. Sim-

Mechanics first and last generation technologies

have different sets of capabilities. Furthermore,

Matlab automatically builds the imitation model of

the parallel robot and the simulation of its motion

(Figure7).

Fig. 7. Model simulation built in Matlab/Simulink

4. PID CONTROL OF THE TRIPOD

The Proportional Integral Derivative (PID)

controlled law of motion management introduces a

new, time-dependent variable, which is denoted by

𝜉 and whose time differential is:

�� = 𝑞. (7)

The previously defined law now receives the

form:

𝜏 = 𝑘𝑝�� + 𝑘𝑣 �� + 𝑘𝑖𝜉. (8)

By combining the previous equations, we

define the behaviour of a manipulative robot with n-

degrees of freedom during its management of the

PID controller:

𝐵(𝑞)�� + 𝐶(𝑞, ��)�� + 𝑔(𝑞) = 𝑘𝑝�� + 𝑘𝑣 �� + 𝑘𝑖𝜉 (9)

or the solution for the equivalent in relation to the

vector of the position is:

[𝜉𝑇0𝑇0𝑇]𝑇. (10)

To achieve the desired position 𝑞𝑑for which 𝜉∗ is a constant, one way is to solve a differential

equation where 𝜏0 is a constant vector and the

solution is given with:

𝜉∗ = 𝑘𝑖−1𝜏0. (11)

If we assign a constant moment to the mani-

pulation robot 𝜏 = 𝜏0, the solution to the previous

equation is simply the position vector 𝑞 and the

velocity ��. In case when the desired position 𝑞𝑑 is a

function of the time, the equation has no solution,

i.e. it can not be expected that the error of position

q is tending to 0. In the best case also assuming that

the initial error of the positions 𝑞(0) and ��(0) the

velocity are small, so the error of positions 𝑞 over

time remains limited. In this case, the PID controller

is connected to the mobile platform, as shown in

Figure 8.

The P, I, and D amplifiers can be modified by

clicking in the according blocks. The PID controller

manages the trajectory that describes the mobile

platform, which is actually the ultimate goal of the

parallel robot controllability. By changing the valu-

es of the proportional, differential and integral amp-

lifier, its position, velocity and acceleration are

changing. Namely, with the aid of a sensor, we can

explicitly obtain the schedules of displacement, spe-

ed and acceleration corresponding to the given

ratios for the amplifiers. To calculate these three

sizes, we create subsystems with mathematical ope-

rations as shown in Figure 9

The subsystems contain blocks with which the

displacement, velocity and acceleration vectors

along the three axes are depicted in one graph as

total displacement, total speed and total accelerati-

on, using the well-known equation:

𝑝 = √𝑝12 + 𝑝2

2 + 𝑝32,

𝑣 = √𝑣12 + 𝑣2

2 + 𝑣32, (12)

𝑎 = √𝑎12 + 𝑎2

2 + 𝑎32


Mech. Eng. Sci. J., 37 (1–2), 79–86 (2019)

Fig. 8. Block diagram in Matlab/Simulink with PID control

Fig. 9. Calculation of the position, velocity and acceleration

5. RESULTS

To show and verify the function of the sub-

systems, the values for the position, speed, and shift

in the values of the amplifiers of the controller P =

0.8, I = 0.2 and D = 0.2 are selected arbitrarily. The

mobility examination of the mobile platform is

proceeded during a period of 3 seconds (T = 3). The

graphs for the position, velocity and acceleration

accordingly are given in Figure 10. These graphs

were obtained for the chosen arbitrary values of the

PID controllers amplifiers that we have set in advan-

ce.


Маш. инж. науч. спис., 37 (1–2), 79–86 (2019)

The graphs will be different for different

amplifier values. This means that with the PID con-

troller we directly influence on the movement of the

centre of gravity of the mobile platform, that is, its

trajectory, which was actually the purpose of its

installation. We also control its speed and accelera-

tion, thus affecting the dynamics of the manipulator.

a)

b)

c)

Fig. 10. Graphs for the a) position, b) velocity and c) acceleration


Mech. Eng. Sci. J., 37 (1–2), 79–86 (2019)

6. CONCLUSION

With the help of the software package "Solid

Works", a new parallel manipulator with three de-

grees of freedom was modelled. The structure of the

manipulator consisted of three legs, each connected

with a rotary pair to the movable and stationary

platform of the manipulator. Direct and inverse

kinematics was considered for this manipulator,

following with simulation of the motion. Finally,

the movement of the mobile platform was control-

led by a PID controller, with reference to the relia-

bility of the trajectory of the mobile platform from

the values of the PID controllers.

Primarily, the purpose of this paper work was

to look at parallel manipulators, whose applications

today are innumerable and spread new horizons in

the robotics industry. Furthermore, the possibilities

of direct communication between the Solid Works

and Matlab/Simulink software packages for model-

ling a parallel manipulator through the Multibody

tool were presented. So far, the application of these

two software packages as independent has perhaps

been more complicated, but through the Multibody

tool, it has become unlimited. The PID controller

was considered as the most used in today's applica-

tions in the technology processes and was used as

an ideal option for managing the parallel manipu-

lator in order achieving complex trajectories which

is widely used and extremely important.

REFERENCES

[1] Xi, F., Li, Y. and Wang, H.: Module-based method for

design and analysis of reconfigurable parallel robots.

Frontiers of Mechanical Engineering, 6 (2), pp. 151–159

(2011).

[2] Xi, F., Xu, Y., Xiong, G.: Design and analysis of a re-

configurable parallel robot. Mechanism and Machine

Theory, 41 (2), pp. 191–211 (2006).

[3] Bi, Z. M., Lang, S. Y.: Kinematic and dynamic models of

a tripod system with a passive leg. IEEE / ASME Trans-

actions on Mechatronics, 11 (1), pp. 108–111 (2006).

[4] Karouia, M., Hervé, J. M.: A three-DOF tripod for genera-

ting spherical rotation. In: Advances in Robot Kinematics,

Springer, Dordrecht, 2000 (pp. 395–402).

[5] Laski, P. A., Takosoglu, J. E., Blasiak, S.: Design of a 3-

DOF tripod electro-pneumatic parallel manipulator. Robo-

tics and Autonomous Systems, 72, pp. 59–70 (2015).

[6] Staicu, S.: Recursive modelling in dynamics of Delta

parallel robot. Robotica, 27 (2), pp. 199–207 (2009).

[7] Lapusan, C., Matis, V., Balan, R., Hancu, O., Stan, S. and

Lates, R.: Rapid control prototyping using Matlab and

dSpace. Application for a planar parallel robot. IEEE

International Conference on Automation, Quality and

Testing, Robotics,Vol. 2, pp. 361–364). IEEE, May 2008.

[8] Jovčevski, D., Djidrov, Marjan, Mickoski, H.: Kinematic

model analysis of a parallel manipulator with six and three

degrees of freedom, Mechanical Engineerring – Scientific

Journal, Vol. 36, No. 2, pp. 137–144 (2018). ISSN 1857–

5293.

[9] Stan, S. D., Manic, M., Maties, V., Balan, R.: Kinematics

analysis, design, and control of an Isoglide3 Parallel Robot

(IG3PR). In: 34th Annual Conference of IEEE Industrial

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Received: May 21, 2019 UDC: 697.34:697.2]:696.2-047.44



LIFECYCLE COSTS COMPARATION BETWEEN DISTRICT HEATING

AND INDIVIDUAL GAS HEATING

Dame Dimitrovski, Dalibor Stojevski

Faculty of Mechanical Engineering, “Ss. Cyril and Methodius” University in Skopje,


[email protected]

A b s t r a c t: The purpose of this work is to define the economically more feasible solution to the air pollution

problem in Skopje through use of district heating (DH) or individual gas heating. Suburb model is Lisiče in Skopje.

Analyzed are the total lifecycle costs of entire city quarter through use of the mentioned heating types. The energy

consumption and CO2 emissions from different lifecycle phases depend on the properties of pipe material, type of

technologies used (during manufacturing the pipe, installing equipment and pumping technologies) and the type of

fluid. Four phases are considered in this lifecycle assessment, which are production and fabrication, transportation to

job site, pipe installation and operation or service phase. As can be concluded, total lifecycle costs in DH system are

lower than the costs for individual gas heating. The slightly higher operating costs are annulled by the costs for

maintenance and CO2, which are significantly larger by use of individual gas heating system. By use of DH system in

the suburb of Lisiče, the emission of PM10/2,5 will be practically extinguished as the DH system uses natural gas as only

source. This will lead to improved air quality in this part of Skopje.

Key words: district heating, gas heating, air pollution, heating costs

СПОРЕДБА НА ТРОШОЦИТЕ ВО ТЕКОТ НА РАБОТНИОТ ВЕК НА СИСТЕМOT

ЗА ЦЕНТРАЛНО ГРЕЕЊЕ И ИНДИВИДУАЛНОТО ГРЕЕЊЕ СО ГАС

А п с т р а к т: Целта на овој труд е да се дефинираат економски исплатливи решенија на проблемот на

загадувањето на воздухот во Скопје преку анализа на системи за централно греење со гас и индивидуално

загревање на објектите со гас. Како модел е земена населбата Лисиче. Во трудот се анализирани параметрите

од целиот работен век на производот (услугата) за двата вида греење. Анализирани се процесите: проектирање,

производство и транспорт на материјалите, вградување и работа на системот. Поради долготрајноста на

системот, управувањето со отпад по завршувањето на работниот век на услугата не е земено предвид. Како

што може да се заклучи, трошоците за централното греење се пониски во споредба со индивидуалното

загревање со гас. Повисоките трошоци кај централниот дистрибутивен систем за топла вода се компензираат

со трошоците за одржување на индивидуалните системи. Со користење централен систем за снабдување со

топла вода, погонуван со природен гас, во населбата Лисиче, емисиите од системите за загревање во овој дел

на градот ќе бидат нула. Па така, за очекување е дека со тоа ќе се подобри квалитетот на амбиенталниот воздух

во овој дел од Скопје.

Клучни зборови: централно греење; греење на гас; загадување на воздух; трошоци за греење

BACKGROUND

Skopje is at the top of most polluted cities in

the world. The situation repeats every heating sea-

son [1]. Figure 1 shows the monthly distribution of

PM10 and PM2,5 in Skopje in 2017.

All relevant studies get to the conclusion that

the air pollution is caused by burning wood which

is most common heating by the individual house-

holds [2, 3].

The city quarter JI03 (Lisiče suburb) is charac-

terized with dense structure of individual houses,


88 D. Dimitrovski, D. Stojevski

Mech. Eng. Sci. J., 37 (1–2), 87–91 (2019)

which the highest percentage use wood in old stoves

as heating source. Figure 2 shows the disposition of

the Lisiče suburb. Figure 3 shows the fuels used for

household heating in Skopje.

Fig. 1. Monthly distribution of PM10/2,5 in Skopje in 2017

Fig. 2. Disposition of Lisiče suburb

Fig. 3. Used type of heating in Skopje area

Detail analysis was made for the entire life-

cycle costs of district heating and individual gas

heating.

The following costs groups were taken into

calculation:

• material costs,

• installation costs,

• exploitation and maintenance costs.

All costs were summarized as a whole for the

entire quarter, in order to find solution which can be

promptly initiated and can lead to the fastest solving

of the air pollution problem.

EXPERIMENTAL

The Lisiče suburb is located in the eastern part

of Skopje. Even though it’s relative close to the city

urban part, its conjuncture can be considered as

rural. For getting info regarding number of objects

and their heat consume, poll through the cadastre

Lifecycle costs comparation between district heating and individual gas heating 89

Маш. инж.науч. спис., 37 (1–2), 87–91 (2019)

was made and the following type of objects were

counted:

As can be viewed from the satellite view,

predominantly the suburb is consisted of individual

houses. According several polls, most widely used

type of heating in areas with dominant individual

houses is the wood heating in stoves [3]. Table 1

shows the number of objects considered in the study

and the heat consume.

T a b l e 1

Objects and heat consume

1 story 2 story 3 story

Number of objects 321 93 2

Heat consume (kW) 3624 2789 76

The relative age of the houses in Lisiče suburb

is > 40 years, with poor thermal insulation. In the

recent years, the trend of improving the energy

efficiency of the houses is obvious. Therefore, we

take average thermal insulation in the calculation.

Taking into consideration the above menti-

oned, the following input parameters were taken

into account for the heat type economic feasibility:

• Equipment is designed for heating of the

whole house;

• Specific heat consume of the houses is taken

as 115 W/m2;

• Design room temperature is 20 ˚C;

• Design ambient temperature is –15 ˚C;

• Heating hours per year is 2745.

RESULTS AND DISCUSSION

Design of district heating system

This part of Skopje does not have district

heating (DH) network. The main DH network under

control of BEG AD is approximately 1000 m from

the potential connection point with the conceptual

secondary and connection line network in Lisiče.

According design parameters (flow velocity, heat

consume…), the main pipeline should be DN150.

The secondary DH network should be 3 km′ DN80.

Connection lines are 15 m′ at DN25. In Table 2, the

prices of components used in central district heating

system are shown.

T a b l e 2

Prices of components used in DH system

Pipes

(EUR/m')

Control valves

(EUR/piece)

Heat meter

EUR/piece)

Inner

installation

(EUR/kW)

DN25 63 590 301 133

DN32 74 826 413

DN40 86 1.062 578

DN50 98 2.360 826

DN65 113 3.340 826

DN80 134 5.310 1.333

DN100 181 / /

DN150 262 / /

DN200 378 / /

The heat station is designed as indirect, with

installation of heat exchanger which separates the

network medium from the indoor installation

medium. Other necessary components and their

costs (installation and VAT included) are:

Design of individual gas system

This part of Skopje does not have gas infra-

structure. The main gas network is approximately

3000 m from the potential connection point with the

conceptual secondary and connection line network

in Lisiče.

According design parameters (flow velocity,

heat consume, etc.), the main pipeline should be

DN100. The secondary gas network should be

HDPE DN65, while the gas connections should be

G3-G10, depending of heat consume. Table 3 shows

the prices of components used in individual gas

system for heating.

T a b l e 3

Prices of components used in gas system

Capacity

(kW)

Boiler

(€)

Connecting line with GMS

(€)

24 770 1.036

28 803 1.036

33 1.306 1.036

55 2.033 1.569

85 3.084 2.369

90 D. Dimitrovski, D. Stojevski

Mech. Eng. Sci. J., 37 (1–2), 87–91 (2019)

Other necessary components and their costs

(installation and VAT included) are:

– Exploitation and maintenance costs of DH

system.

Final yearly heat need of the Lisiče suburb at

6.5 MW heat consume are 7.137 MWh. The costs

towards the DH operator are as follows [5]:

• engaged heat consume – 17.863 EUR/MW/year;

• heat energy price – 35 EUR/MWh.

There is no maintenance costs in this system.

– Exploitation and maintenance costs of indi-

vidual gas system.

Gas boiler efficiency is taken at 92% according

low heating value [4]. This requires 814.216

Nm3/year gas consumption.

The costs for the gas consumption are as fol-

lows:

• gas border price – 354 USD/1000 Nm3;

• import costs – 2% of border price;

• trading margin – 47 EUR/1000 Nm3;

• gas transmission tariff [6] – 27 EUR/1000 Nm3;

• gas distribution tariff [7] – 52 EUR/1000 Nm3.

Maintenance costs are costs for inspection of

the gas boiler and inner installation and cleaning of

chimneys, total 60 EUR/house.

– CO2 footprint in production and installation

phase of DH system [8].

The energy consumption and CO2 emissions

from different lifecycle phases depend on the pro-

perties of pipe material, type of technologies used

(during manufacturing the pipe, installing equip-

ment and pumping technologies) and the type of

fluid. Four phases are considered in this lifecycle

assessment, which are production and fabrication,

transportation to job site, pipe installation and

operation or service phase. The working period of

this heating is 40 years.

– CO2 footprint in production and installati-

on phase of individual gas system.

The working period of specific components of

this heating varies between 10 (boilers) and 40

(pipes) years. CO2 emissions from the DH and gas

system in the early phase are given in Table 4 and

Table 5.

T a b l e 4

Emission of CO2 in early phase of DH system

DN25 DN150

Pipes production

Weight (kg/m') 7,06 12.480

Total length (m) 40,66 6.000

CO2 in production (t) 585 1620

Pipes transport

Distance between site and plant (km) 4000 4000

Max pipe sections per truck 165 29

Total truck sessions 6 17

Total fuel consumption (l) 10.070 27.881

CO2 per fuel (CO2/l) 3 3

Total CO2 for transport (t) 27 74

Pipes installation

Necessary excavation/fill hours (h) 5.200 5.000

Fuel consumption (l/h) 10 10

Total fuel consumption (l) 52.000 50.000

CO2 per fuel (CO2/l) 3 3

Total CO2 for installation (t) 154 148

Total CO2 emission of DH system in early

phase is 2608 t.

T a b l e 5

Emission of CO2 in early phase of gas system

DN20 DN65 DN100

Pipes production

Weight (kg/m') 0,12 1,05 3,13

Total length (m) 6240 3000 3000

CO2 in production (t) 11 45 134

Pipes transport

Distance between site and plant (km) 360 360 360

Max pipe sections per truck 4.000 378 176

Total truck sessions 1 1 2

Total fuel consumption (l) 144 144 288

CO2 per fuel (CO2/l) 3 3 3

Total CO2 for transport (t) 0,4 0,4 1

Pipes installation

Necessary excavation/fill hours (h) 1.560 1.000 1.250

Fuel consumption (l/h) 10 10 10

Total fuel consumption (l) 15.600 10.000 12.500

CO2 per fuel (CO2/l) 3 3 3

Total CO2 for installation (t) 46 30 37

Total CO2 emission of individual gas system in

early phase is 303 t.

Lifecycle costs comparation between district heating and individual gas heating 91

Маш. инж.науч. спис., 37 (1–2), 87–91 (2019)

CONCLUSION

Comparation of costs of different heating types

and CO2 emissions is given in Table 6.

T a b l e 6

Lifecycle CO2 emission and cost comparison

DH Gas

Total CO2 emission in early

phase (tCO2) 2608 303

Total CO2 emission in

exploitation (tCO2) 16.869 48.623

Total CO2 emission (tCO2) 19.477 48.926

CO2 price (EUR/t) 22 22

Total CO2 costs (EUR) 428.500 1.076.362

Total investment costs (EUR) 2.743.463 3.664.730

Total operating costs (EUR) 18.399.652 18.151.475

Total maintenance costs (EUR) – 1.250.000

Total costs (EUR) 21.571.615 24.142.567

As can be concluded, total lifecycle costs in

DH system are lower than the costs for individual

gas heating. The slightly higher operating costs are

annulled by the costs for maintenance and CO2,

which are significantly larger by use of individual

gas heating system.

By use of DH system in the suburb of Lisiče,

the emission of PM10/2,5 will be practically extin-

guished as the DH system uses natural gas as only

source. This will lead to improved air quality in this

part of Skopje.

Acknowledgements. This work was supported by

the colleagues from Balkan Energy Group. The authors

would like to thank all of them for providing the data.

REFERENCES

[1] European Environment Agency: Air Quality in Europe, 23

(2015).

[2] Tashevski, D., Filkovski, R., Armenski, S., Dimitrovski,

D., Shesho, I.: Defining techno-economic optimal and

ecologic sustainable heat structure of Skopje, 59 (2017).

[3] Dimitrovski, D.: UNDP Support: Analysis of household

heating practices in Skopje Valley, 2017.

[4] Or, G., Lelyveld, T., Burton, S.: Final Report: In-situ mo-

nitoring of efficiencies of condensing boilers and use of

secondary heating, Prepared by: GASTEC at CRE

LtdAECOM EA Technology, Prepared for: The Energy

Saving Trust, Contract Number: GaC3563, June 2009.

[5] Energy Regulatory Agency of Macedonia: Decision for

heat price for supply Heat Balkan Energy, 2018.


gas transmission tariff for GA-MA, 2019.


gas distribution tariff for Kumanovo Gas, 2019.

[8] Khan, L. R., Tee, K. F.: Quantification and comparison of

carbon emissions for flexible underground pipelines,

Canadian Journal of Civil Engineering, 42 (10), pp. 728–

736 (2015).




Received: January 20, 2018 UDC: 633.18:664.782.4-97

Accepted: February 20, 2018


DRYING CONDITIONS FOR PADDY PROCESSING

IN MIXED-FLOW HIGH-CAPACITY PLANT

Filip Mojsovski



[email protected]

A b s t r a c t: A research was conducted to obtain information on needed procedures for transforming one uni-

versal cereal dryer in special equipment for paddy. Harvested paddy was dried under controlled air conditions in con-

tinuous-flow high-capacity grain dryer. The realization of the planned study was carried out in three steps: 1) cor-

rection of dryer construction, 2) insertion of intermittent drying process, and 3) selection of correct drying conditions.

Intermittent drying process was studied by tempering paddy during its processing. In a drying section two zones sys-

tem was exploited, zone 1 with air temperatures up to 45oC, and zone 2 with air temperatures up to 40 oC. In a cool-

ing section air temperatures up to 26 oC were used. Variations in moisture content, between the grains from two suc-

cessive horizontal elements of the dryer, were in the range of near one percentage points. In the first horizontal ele-

ments of heating section, the variation of moisture content wet basis was two times higher than in the rest horizontal

elements of drying section. Correct drying conditions, for local paddy varieties, were selected and are reported.

Key words: food drying; paddy; drying conditions

УСЛОВИ НА СУШЕЊЕ ЗА ТРЕТМАН НА ОРИЗОВА АРПА

ВО ИНДУСТРИСКА СУШИЛНИЦА СО КОМБИНИРАНО СТРУЕЊЕ

А п с т р а к т: Спроведено е истражување со цел да се добијат информации за потребните постапки при

трансформирањето на една универзална житна сушилница во специјална опрема за оризова арпа. Ожнеаната

оризова арпа е сушена, при контролирани состојби на воздухот, во индустриска сушилница со континуиран

протек на воздух. Реализацијата на планираната студија беше спроведена во три етапи: 1) приспособување на

конструкцијата на сушилницата, 2) воведување сушење со прекини и 3) избирање правилни услови на суше-

ње. Процесот на сушење со прекини е проучуван со менување на температурата на оризовата арпа во текот на

нејзиниот третман. Во делот за сушење беше користен систем со две зони, зона 1 со температури на воздухот

до 45oC, и зона 2 со температури на воздухот до 40 oC. Во делот за ладење беа користени температури на воз-

духот до 26 oC. Промените на содржаната влага во зрната од два сукцесивни хоризонтални елементи на

сушилницата беа во опсег од близу еден процент. Во првите хоризонтални елементи од делот за греење про-

мената на содржаната влага по влажна основа беше два пати поголема од онаа во другите хоризонтални еле-

менти од делот за греење. Избрани се оптимални услови за сушење на локалните сорти оризова арпа и се

објавуваат.

Клучни зборови: сушење на храна; оризова арпа; услови на сушење

INTRODUCTION

It is certain that rice is among the world basic

foods and feeds. The annual world production of

paddy was 650 million tonnes in 2007 and 770

million tonnes in 2017 [1].

Paddy hull is removed during the milling pro-

cess in order to produce white rice. In the milling

process approximately 70 % white rice is produc-

ed, because the loss for dehulling is up to 30 % [2].

94 F.Mojsovski

Mech. Eng. Sci. J., 37 (1–2), 93–98 (2019)

Paddy is harvested at high moisture content

and must be dried. Drying of grain, in forced con-

vection system, is the most practiced preservation

method. Estimation of the quantity of air required

to remove the moisture from the dried rice is based

on psychrometric [3, 4]. Of all cereals, rice is

probably most difficult to process without quality

loss.

Immediate drying of the harvested paddy is

essential to prevent quality deterioration. The qual-

ity characteristics of paddy can be seriously dam-

aged by early harvesting (immature and high-

moisture content grain), incorrect combine settings

(broken kernels) and rapid drying (stress-cracked

kernels). To obtain the desired product quality, the

pre and post treatment of dried product is also im-

portant. Radical cleaning and correct storage are

necessary.

In the five steps grain processing, harvesting-

drying-storage-handling-transportation, drying is

the duty of a thermal engineer.

Paddy drying is thermal process of simultane-

ous heat and mass transfer. The kernel is capillary-

porous body. The pore, tiny opening trough which

fluids may pass, are partially filled with liquid wa-

ter and partially filed by mixture of air and water-

vapor. In the thermal drying process, the moisture

evaporates and leaves the kernel. The movement of

evaporated moisture inside the grain is influenced

by capillary forces, but at the kernel surface, partial

vapor pressure difference between the water-vapor

in the kernel and surrounding air, is driving force.

The moisture movement in capillary-porous body

due to the diffusion and Еarth gravitation is also

present, what additionally complicates the under-

standing of the matter. Existing food drying theory

cannot be sufficient to evaluate the drying rate un-

der different drying conditions. It remains to be

seen if the solution can be find using laboratory

and field tests.

Throughout the harvest season, huge quanti-

ties of paddy are available daily and the need for

reduction of drying time, favors the use of high-

capacity dryers.

In the actual research, tower-type mixed-flow

dryer is exploited (Figure 1).

Composed of 17 horizontal elements, with di-

mension 3 × 3 × 1 m, the dryer reaches 26 m

height. The inner construction of the horizontal

element provides mixed-flow in the dryer. The rel-

ative direction of the air and the grain in this

mixed-flow system is a combination of crossflow,

concurrent and countercurrent flow. Therefore, the

variation in the kernel moisture content is small.

This is the major advantage of mixed-flow dryer

application.

Fig. 1. Tower-type cereal dryer

1 – filling module, 2 – horizontal element,

3 – lower horizontal element, 4 – hot air duct,

5 – cold air duct, 6 – unloading auger

The moist grain kernels, after cleaning, are in-

troduced at the upper side of the dryer, into the

drying section and then into the cooling section.

In a drying section heated air carries heat into

the paddy mass, to evaporate its moisture and then

removes the evaporated water out of the system.

The amount of moisture removed from paddy, per

horizontal element of drying section, should be

controlled and limited.

In a cooling section the ambient air removes

heat from the paddy mass and then discharges it,

into the environment.

Drying section consists of 13 horizontal ele-

ments, each 1 m high, built-up in six groups, 3 + 2

Drying conditions for paddy processing in mixed-flow high-capacity plant 95

Маш. инж. науч. спис., 37 (1–2). 93–98 (2019)

+ 2 + 2 + 2 + 2. Every group is separated by 0.5 m

high horizontal element. These five lowers hori-

zontal elements provide the intermittent regime of

drying.

Intermittent cereal drying process uses dis-

continuous heat input. During the pause in the heat

supply, the moisture has enough time to be dislo-

cated within the material. This kind of drying pro-

cess can improve the quality of dried product [5].

Intermittent cereal drying has already wide

application in practice.

High-capacity cereal-drying systems improve

grain quality as a result of the intermittent drying.

A tempering section or tempering period separates

two adjoining drying stages. This results in a reten-

tion time, adequate to sufficiently reduce the tem-

perature and moisture content gradients in the ker-

nels, before subsequent further drying.

Cooling section consists of 4 horizontal ele-

ments, in which the hot, dried grain is cooled with

the ambient air, to within 5oC of its dry-bulb tem-

perature. During the cooling process, some mois-

ture is also removed.

According to the manufacturer documenta-

tion, the actual dryer is designed as universal, for

all cereals drying.

OBJECTIVE AND PROCEDURES

The purpose of this paper is to summarize the

results of the efforts to make this type of dryer pri-

marily convenient for paddy drying.

The realization of the planned study was car-

ried out in three steps: 1) correction of dryer con-

struction, 2) insertion of intermittent system of dry-

ing, and 3) selection of correct drying conditions.

In the phase of preparation for planned tests,

air distribution was modified to enable zonal air-

flow and uniform air velocities at the entrance of

drying room. To satisfy the exact needs of drying

process, the drying space was organized as multi-

thermal zone system [6].

Grain cleaner was introduced, as auxiliary but

important equipment, one that can enhance the dry-

er performance. In the case when cleaning is not

enough effective, accumulated impurities obstruct

the correct grain flow in the horizontal elements of

the mixed-flow dryer.

Rice is highly sensitive to amount and intensi-

ty of received heat during the drying. The experi-

ence, from industrial drying practice, shows that

drying rice slowly, with intermittent tempering, is

a suitable drying method.

The level of drying air temperature has basic

influence on grain drying. Temperature gradients

in a kernel, cause expansion in the nonhomogene-

ous grain material. Drying process in which paddy

temperature reaches 38 oC, provoke cracks in the

interior of the kernel. Then, in the milling process,

the percentage of whole kernels will be not toler-

antly low.

Only during the pass-through in the first hori-

zontal elements of drying section, since paddy is

still cool and relatively high in moisture, the tem-

perature can be slightly higher.

The resistance to the airflow into drying room

is a result of energy lost through friction and turbu-

lence. It depends on three factors: the rate of air-

flow, the surface and shape characteristics of pad-

dy, and the realized voids in the horizontal ele-

ments during the mutual movement of air and pad-

dy. Paddy has the roughest hull surface of all cere-

als. Higher rate of airflow was provided by pres-

sure build-up on the air-entrance side.

The airflow rates necessary to dry and cool

the grain mass are provided by centrifugal fans.

Tests were carried out in order to find the correct

fan regime. The airflow, at the entrance of heating

and cooling section, was controlled by measure-

ments. At the same measuring points, temperature

and relative humidity of air were registered.

The intermittent drying is realized with con-

structive and functional interventions. All five

lower horizontal elements are built as vertical

ducts and have not direct drying-air supply. The

grain moves within the lower horizontal element

but is not heated. The second kind of pause in heat-

ing is controlled by unloading auger and heating

process. Simultaneously grain movement and heat

supply are stopped. Duration of tempering period

was evaluated by tests.

Drying conditions (“the combination of dryer

construction, dried product state during the process

and drying medium state during the process”),

were selected as correct, in the case when the dried

product was of first-rate quality. Drying conditions

were investigated by computer simulation and

fieldwork activities [7].

The paddy state in drying process was con-

trolled continuously. The tests procedure contained

measurements, visual evaluation and test judging.

Dried material state (initial, zonal and final

moisture content and temperature), drying medium

96 F.Mojsovski

Mech. Eng. Sci. J., 37 (1–2), 93–98 (2019)

state (temperature, relative humidity, flow) and

dryer function (zonal drying time, energy con-

sumption) were controlled by measurements. The

field tests were necessary to verify the expected

dried rice quality, reached under specified drying

conditions.

Dried paddy state control was realized by

sampling in time and space. Measuring platforms

were built at the base level of every horizontal el-

ement. Sampling tube enables to take specimen

from all horizontal elements during the drying pro-

cess. It is constructed as tube-in-tube device, which

collects grains from measuring points for laborato-

ry analysis. The movement of sampling tube into

the paddy mass was obstructed because of the

tough and abrasive nature of husks. Direct meas-

urement, moisture content determination method,

with apparatus based on infra-red radiation, was

used in laboratory conditions. Drying medium state

was controlled by digital psychrometers and ane-

mometers. Attention was concentrated on regime

parameters, operation problems, diagnostics and

plant efficiency.

RESULTS AND DISCUSSION

In the period of September to November,

when local paddy varieties, Monticelli, Saint An-

drew and RS76 are dried, the atmospheric air tem-

perature range, at the location of drying plant, is

between 30 and 2 oC. For these temperatures, from

the climatic curve, the level of relative humidity is

graphically evaluated from 35 to 80 %, and en-

thalpies from 54 to 10 kJ/kg [8].

Psychrometric chart, with coordinates of tem-

perature and humidity ratio, was used for conven-

ient graphical illustration of drying air states

changes during its heating and humidifying (Figure

2).

Fig. 2. Psychrometric diagram

The comparison of data, obtained from the

psychrometric diagram for the two extreme atmo-

spheric states (2oC, 80 % and 30 oC, 35 %), shows

great difference in needed amount of heating en-

ergy, for more than three times, ∆i for (1L, 2L) = 49

– 10 = 39 kJ/kg, and ∆i for (1H, 2H) = 65 – 54 = 11

kJ/kg.

By examination, it was found that the heat de-

mand of the dryer, can be provided by applying

paddy husk as fuel. Heating values of up to 15 000

kJ/kg were obtained, by measuring the heat gener-

ated during combustion of local paddy husk in cal-

orimeter. Such an approach was considered as

most desirable from an ecological standpoint [9].

Drying conditions for paddy processing in mixed-flow high-capacity plant 97

Маш. инж. науч. спис., 37 (1–2). 93–98 (2019)

The option for recirculation, of part of the

dryer exhaust air, was examined and abandoned as

not attractive. The grain was cleaned before it was

dried. The used grain cleaner removed up to 1 kg

weed seed and trash from 100 kg of processed

paddy. The level of examined parameters, relevant

for the selection of drying conditions, is presented

in Table 1.

T a b l e 1

The relevant data from field and laboratory tests

Parameter Value

1. Air

1.1. Atmosphere,

– Temperature, oC 2 – 30

1.2. Drying room

1.2.1. First two horizontal elements,


1.2.2. Third to thirteenth horizontal element,


1.2.3. Fourth to seventeenth horizontal element,


2. Paddy

2.1. Filling auger:

– Moisture content, wet basis, % 16 – 28


2.2. First two horizontal elements:



2.3. Third to thirteenth horizontal element:



2.4. Fourteenth to seventeenth horizontal element:



2.5. Unloading auger:



Paddy was harvested at an average moisture

content, wet basis, between 18 and 30 %, during

the wet harvest season, and between 16 and 26 %,

during the dry harvest season. Up to 8 % difference

in initial moisture content was registered, between

the most mature and least mature kernels.

Variations in moisture content, between the

grains from two successive horizontal elements of

the dryer, were in the range of one percentage

points. In the first horizontal elements of heating

section, the variation of moisture content wet basis

was two times higher than in the rest horizontal

elements of drying section.

Regarding to the temperature regime, at the

entrance of drying room, three zones system was

selected as a correct one. In the zone 1, the first

98 F.Mojsovski

Mech. Eng. Sci. J., 37 (1–2), 93–98 (2019)

two horizontal elements of drying section, air tem-

peratures up to 45oC were used, in the zone 2, the

rest of horizontal elements of heating section, air

temperatures up to 40oC were used, and in the zone

3, four horizontal elements of cooling section,

temperatures up to 26 oC were used.

The exit kernel temperature of 35 oC was not

surpassed.

CONCLUSIONS

Dryer construction was adjusted for zonal

paddy drying and requirements of measuring equi-

pment.

True drying intensity was reached with in-

volving intermittent paddy tempering of up to 2

hours.

Correct drying conditions, for local rice varie-

ties, were obtained.

REFERENCES

[1]FAO (Food and Agricultural Organization of the United

Nations), Faostat, Data, 2019.

[2] Brouker, D. B., Bakker-Arkema, F. W., Hall, C. W.:

Drying and Storage of Grain and Oilseeds, Van Nostrand

Reinhold, New York, USA, 1992.

[3] Gatley, D. P.: Understanding Psychrometrics, American

Society of Heating, Refrigerating and Air-Conditioning

Engineers, Atlanta, USA, 2013.

[4] ASHRAE (American Society of Heating, Refrigerating

and Air-Conditioning Engineers), Handbook Fundamen-

tals, Chapter 1: Psychrometrics, Atlanta, USA, 2013.

[5] Aquerreta, J., Iguaz, A., Arroqui, C., Virseda, P.: Effect

of high temperature intermittent drying and tempering on

rough rice quality, Journal of Food Engineering, Vol. 80,

No. 2, pp. 611–618 (2007).

[6] ASHRAE (American Society of Heating, Refrigerating

and Air-Conditioning Engineers), Handbook HVAC Ap-

plications, Atlanta, USA, 2011.

[7] Mojsovski, F.: Drying conditions for rice and tomato, In-

ternational Journal of Mechanical Engineering and Tech-

nology, Vol. 5, No. 10, pp. 78–85 (2014).

[8] Mojsovski, F.: Analysis of humidity level in psychromet-

ric thermal processes, PhD Thesis, Faculty of Mechanical

Engineering, Skopje, Macedonia, 2007 (in Macedonian).

[9] Mojsovski, F., Dimitrovski, D.: Thermal conditions for

rice parboiling process realised with the use of renewable

energy resource, Journal of Environmental Protection

and Ecology, Vol. 16, No. 2, pp. 699–704 (2015).




Received: June 6, 2019 UDC: 725.21.05:624.012.6]:[519.612:531.2



CONCEPT FOR STUDENT GLASS PAVILION

Bojana Trajanoska, Elisaveta Dončeva, Daniela Pana, Hristijan Gjorgievski



[email protected]

A b s t r a c t: Contemporary architecture and engineering are based on combining structural glass and steel,

where glass is used for its transparency and steel for its strength. The intention behind this pavilion concept is decreasing

the lack of modern glass structures in our surrounding. This article describes the FE modelling and analysis of а glass

structure planned tо be located in the technical campus of the Faculty of Mechanical Engineering in Skopje. The final

exterior of the structure is consisted of five glass frames adhesively bonded and mechanically connected with bolts

which give the support of the structure and hold the façade and roof panels. Different scenarios were presented regard-

ing the stability and safety of the glass structure. The carried out FEM simulations are presented, based on predicted

static loads, according to the pavilion's location and the climatic parameters. At the end of this article, visual represen-

tation of the CAD model within the campus space is given.

Key words: glass pavilion; steel connection; structural glass; state of the art; finite element analysis

КОНЦЕПТ ЗА СТУДЕНТСКИ СТАКЛЕН ПАВИЛЈОН

А п с т р а к т: Модерната архитектура и инженерство се темелат на комбинирањето на конструктивно

стакло и челик, при што стаклото се користи поради провидноста, а челикот поради својата јакост. Овој кон-

цепт за студентски павилјон произлегува од недостигот на модерни стаклени конструкции во нашата околина.

Трудот го опишува моделирањето и анализата со метод на конечни елементи на конструкција од стакло пла-

нирана да се постави во техничкиот кампус на Машинскиот факултет во Скопје. Крајниот надворешен изглед

на конструкцијата се состои од пет стаклени рамки атхезивно споени и механички зајакнати со завртки, кои го

даваат скелетот на конструкцијата на која се поставуваат стаклените фасадни и покривни панели. Во поглед на

стабилноста и безбедноста на стаклената конструкција, прикажани се различни конструктивни случаи. Презен-

тирани се извршените симулации со примена на методот на конечни елементи, при што статичките оптова-

рувања се пресметани врз основа на локацијата и климатските услови. Визуелната репрезентација на моделот

CAD е прикажана на крајот од трудот каде што се забележува хармоничното совпаѓање на конструкцијата со

околината на техничкиот кампус.

Клучни зборови: стаклен павилјон; челични врски; конструктивно стакло; преглед на постојните трендови;

метод на конечни елементи

1. INTRODUCTION

In the modern architecture and engineering,

structural glass elements tend to replace the tradi-

tional structural materials, like steel or concrete.

This dramatic change brought a new trend in glass

roofs and external glass frames in home living. The

two primary factors for using structural glass over

any other building materials are innovative day-

lighting and transparency, which empower a sense

of unlimited space [2, 5]. Aditionally these reasons

are basic requirements when designingл a student

friendly environment for continuous learning or group

working.

Although structural glass cannot be compared

with steel in terms of durability and toughness, it is

the only transparent material with high strength that

can be used in many contemporary load-bearing

structures. Strength values for structural glass de-

sign and its application are summarized in Table 1.

100 B. Trajanoska, E. Dončeva, D. Pana, H. Gjorgievski

Mech. Eng. Sci. J., 37 (1–2), 99–105 (2019)

T a b l e 1

Strength values of structural glass [4]

(MPa)

Compressive strength 880 – 930

Tensile strength 30 – 90

Bending strength 30 – 100

The high brittleness of the structural glass

makes it risky to use in crowded locations because

under tensile loads, any surface crack might cause

failure of the glass element.

One of the common solutions regarding this

problem is using treatment such as annealing, tem-

pering and heat strengthening, as well as laminating

in order to improve the mechanical properties and

structural characteristics. Laminated glass has be-

come extensively used as a safety glass in modern

hybrid structures due to the polymeric interlayer

that holds together the elements pieces when shat-

tered. The interlayer, typically PVB or EVA, keeps

the glass plies together even broken, constraining

from breaking into large sharp pieces. Different

types of glass breaking are shown in Figure 1.

tempered laminated annealed

Fig. 1. Breaking of common glass types

The low ductility and the high compressive

strength of the glass allows connections with greater

strength and hardness, like the ones with stainless

steel. Bolted connections (Figure 2) are used for

connecting glass elements where stress concentra-

tions may occur. Regarding the performance of the

bolt, forces up to 30 kN can be transmitted per bolt

[6]. In addition to prevent restraint forces, the num-

ber of bolts should be as minimal as possible in fa-

vor of greater bolt diameters.

Based on the above mentioned structural char-

acteristic, the mechanical behavior the transparency

and the inovative daylighting prospects of the struc-

tural safety glass as a laminated glass, it is chosen

as the most adequate material for designing the stu-

dent pavilion accommodating new modern concepts

with psychological benefits.

Fig. 2. Bolt connection [6]

Concept for student glass pavilion 101

Маш. инж.науч. спис., 37 (1–2), 99–105 (2019)

2. CONCEPT

The student glass pavilion idea arouse from the

need of creative and inovative working space which

students can use in their spare time at the technical

campus of the Faculty of Mechanical Engineering

in Skopje, and later the concept was introduced ac-

cordingly.

The glass pavilion is 5 × 5 × 2.5 m, supported

on a concrete fundament where steel groundwork is

placed. The contact glass-steel is prevented with

rubber installed inside the groundwork. The glass

columns and beams are formed of tempered glass,

joint with PVB, giving a high strength laminated

panel (Figure 3).

Fig. 3. Structural members

The lateral and horizontal glass panels that

confine the structure consists of one fully tempered

glass ply and heat-strengthened ply with inner PVB

layer. Dimensions of the structural members are

given in Table 2.

When designing, a previously detailed plan is

required. Furthermore, a comprehensive research

and calculations were carried out in order to realize

the concept of glass pavilion. Finally, a flow dia-

gram with various steps of work is presented (Fig-

ure 4).

Fig. 4. Concept realization steps

A state of the art research has been done in the field

of glass building construction. Wilson reviews the Glass

Reading Room of the Arab Urban Development Institute

in Riyadh, Saudi Arabia (Figure 5) [2]. The glass cube is

formed of laminated glass panels, connected with friction

grip connections in order to provide stability through the

frame that carries the applied loads.

T a b l e 2

Dimensions of designed structural members

Structural

member

Glass type, layer of

glass (mm)

Dimensions

L × W × H (mm)

Column 1 fully tempered,

2 × 10 200 × 20 × 2500

Inner column 1 fully tempered,

4 × 10 200 × 40 × 2300

Beam 1 fully tempered,

4 × 10 5000 × 40 × 200

Column 2 fully tempered,

2 × 10 200 × 20 × 2500

Inner column 2 fully tempered,

4 × 10 200 x 40 x 2300

Beam 2 fully tempered,

4 × 10 920 × 40 × 200

Roof pane

fully tempered

1 × 5 + heat

strengthened

1 × 5

2500 × 1000 × 10

Façade pane

fully tempered

1 × 10 + heat

strengthened 1 × 5

2500 × 2500 × 15

Fig. 5. Glass Reading Room in AUDI in Riyadh, Saudi Arabia

[2]

In [10] the new pavilion located in Zurich,

Switzerland (Figure 6) is analyzed). Matt-finished

stainless-steel frame and colored but transparent

glass, are the primary exterior details that give this

polygonal-plan structure compliance with the envi-

ronment and fulfill the illumination requirements.


Mech. Eng. Sci. J., 37 (1–2), 99–105 (2019)

Fig. 6. The color glass pavilion in Zurich, Switzerland [10]

All glass enclosure is discussed in [3, 7], built

at the Leibniz Institute for Solid State and Material

Research in Dresden, Germany (Figure 7). Their

main goal is to describe the arrangement of the stru-

ctural members, frame assembly and final installla-

tion. The fully glazed enclosure is made from lami-

nated safety glass, bonded to the frame with a struc-

tural silicon adhesive as a joining technique. Hence,

the glass corners are joint with acrylate adhesives,

which give an exclusively transparent outlook.

Fig. 7. All glass enclosure at Leibniz Institute in Dresden,

Germany [3]

Breakthrough in the application of structural

glass was building the Apple Inc glass cube, the

Fifth Avenue, store located in New York City,

which was the first of a kind [1]. The structure itself

shows functionality and simplicity. First glass cube

(Figure 8) connected the engineering with the art;

the second cube (Figure 9), further enhanced that

connection. The limiting factors of the production

technologies of glass resulted in a glass cube with

164 units joined, forming a standing art piece [1].

Fig. 8. Original glass cube – Apple store

Fig. 9. New glass cube- Apple store

The advancement in the production technology

of structural glass was validated with constructing

the second glass cube. Thirty-five units joined to-

gether proved that glass production has moved for-

ward. Comparing the two of them (Table 3), it is in-

evitable not to see the difference in the roof design.

Two spanning beams with secondary roof beams

from sides and between the spanning beams holed

with roof fins. The façade panes were able to be as

large as 15 m × 3.6 m, which gave the final look of

the second glass cube.

The reduction of the number of the glass struc-

tural members in the new Apple store, led to fewer

glass-steel connections. One of the few reasons for

rebuilding this glass cube was to establish the new

developed connection that holds the glass panes to-

gether (Figure 10). Before it was completed, a nu-

merical analysis was run with particular attention to

the interaction between the glass, interlayers and fit-

tings. The connection model (Figure 11) confirmed

the expected behavior of the joined materials [1] and

let to a unique challenge- rebuilding the glass cube.


Маш. инж.науч. спис., 37 (1–2), 99–105 (2019)

T a b l e 3

Comparison of the structural members

of the two Apple glass cubes [1]

Building part Cube 1 Cube 2

Columns 5 per elevation

× 4 = 20

2 per elevation

× 4 = 8

Façade panles

(incl. doors)

72 12 + 2 doors + 2

side lights = 16

Roof beams 25 at 3.3 mm + 10

at 1.6 m = 35

2 at 10 mm + 7

at 3.3 m = 9

Roof panles 36 3

Entrance canopy 1 1

Subtotals 109 panels

20 fin columns

35 beams

20 panels

8 fin columns

7 beams

Total 164 glass units 35 glass units

Fig. 10. New developed fitting [1]

Fig. 11. Local connection model [1]

3. STRUCTURAL ANALYSIS

This paragraph shows the results of different

analysis performed on these article subject con-

cepts. Using laminated safety glass, all bearing ele-

ments were tested using FEM analysis, including

the enclosed structure itself. The frame members,

stated as glass beams and columns, are made of fully

tempered glass layers, each with thickness 10 mm.

The glass frame ware tested separately, as a primary

bearing column-beam assembly. Mainly, it was ex-

pected a local stress to occur between the glass and

the stainless-steel connection, because of the differ-

ent behavior of the materials under loading condi-

tions (Figure12).

Fig. 12. Stress distribution of the structural frame

However, significant displacement was evalu-

ated centrally on the glass beam, with maximum

displacement of 0.182 mm (Figure 13).

Fig. 13. Maximum displacement of the structural frame:

column-beam

Regarding the above-analyzed factors, three

different scenarios were examined under the same

load conditions (Table 4).

T a b l e 4

Scenarios for FEM analysis

Scenario No. Description

Scenario 1 Structured without support beam and column 2,

roof panel thickness 10 mm

Scenario 2 Structured with support beam and column 2,

roof panel thickness 15 mm

Scenario 3 Structured with support beams and five cross

beams with adhesive fittings, roof panel

thickness 10 mm

A brief comparison of the FEM results is given

in Table 5 and a significant explanation is summa-

rized.


Mech. Eng. Sci. J., 37 (1–2), 99–105 (2019)

T a b l e 5

Comparison of FEM results

Scenario Max. stress

(MPa)

Max. displacement

(mm)

Scenario 1 13.80 26.39

Scenario 2 7.39 6.23

Scenario 3 7.96 7.57

The stress distribution is present for each sce-

nario and remarkably lower stresses were observed

on the front and back façade panes of Scenarios 2

and 3 (Figures 16 and 18, respectively), when com-

pared to stress result from the Scenario 1, shown in

Figure 14

The displacement analysis of Scenario 1 pre-

sented in Figure 15 shows considerably larger dis-

placement of the front and back façade panes under

buckling behavior, while the rest members of the

structure are sufficiently substantial for the sugges-

ted scenario. On the other hand, the results obtained

from both, Scenarios 2 and 3, illustrate smaller dis-

placement gradient (Figures 17 and 19, respective-

ly).

Fig. 14. Scenario 1 – Von Mises stress

Fig. 15. Scenario 1 – Displacement






Маш. инж.науч. спис., 37 (1–2), 99–105 (2019)

The exemplify results are due to the additional

central support frame (Scenario 1 is modeled with-

out the support beams and columns).

Another conclusion can be outlined from the

simulation analysis. As mentioned before, glass has

high compressive strength, but it depends on the

size of the glass panel [9]. The larger the size is the

more chance of finding critical imperfections and

defects in the glass element. The buckling phenom-

ena in glass panels under compression is frequent

problem in all glass structures [11]. Based on this

knowledge, laminated glass columns are arranged

on both, left and right side of the façade for support

and preventing sudden failure. Considering these

side columns arrangement, no significant stresses

nor displacement were determined in none of the

scenarios.

4. CONCLUSIONS

This comprehensive study on structural glass

student pavilion opens the possibility for conversion

of creative and innovative project. The mechanics

and safety for this structure was proven by using

FEM analysis on each scenario under static loads.

Scenario 3 was chosen as an eventual structural so-

lution for further detailed and accurate technical de-

velopment (Figure 20).

Fig. 20. Visual representation of the student glass pavilion

located in the technical campus in Skopje

Furthermore, the preceding results of the stress

and deformation that occurred in Scenario 3 were

dependable and rational when choosing the final

concept as well as the total weight of the glass struc-

ture.

The vast field of application of the glass struc-

tures is evaluated by the state of the art, which are

serving different functions. While being the driving

factor, safety is the main concern when designing

and constructing glass structure. Simplicity and the

ability to comply with the environment is one of the

benefits of an all-glass structure, which implies on

the physiological state of the users.

REFERENCES

[1] Bostick, C., O'Callaghan, J.: The Apple glass cube: Ver-

sion 2.0, In book: Challenging Glass 3 & Conference on

Architectural and Structural Applications of Glass, Tech-

nical University (TU) Delft, The Netherlands, 2012.

[2] Wilson, P.: All-glass enclosures – Spaces for working and

living, In book: Challenging Glass 4 & COST Action

TU0905 Final Conference, pp. 641–647, 2014.

[3] Weller, B, Nicklisch, F., Prautzsch, V. Döbbel, F.,

Rücker, S.: All glass enclosure with transparently bonded

glass frames. In: Challenging Glass 2 – Conference on Ar-

chitectural and Structural Applications of Glass, Bos,

Louter, Veer (Eds.), TU Delft, May 2010.

[4] Fröling, M.: Strength design methods for glass structures,

Doctoral thesis, Lund, Sweeden, Division of Structural

Mechanics, Lund University, 2003, pp. 9–15.

[5] Louter, C., Bos, F., Belis, J., & Lebet, J. P. (Eds.): Chal-

lenging Glass 4 & COST Action TU0905 Final Conferen-

ce. CRC Press, 2014.

[6] Wurm, J.: Glass Structures – Design and Construction of

Self-supporting Skins, Birkhäuser Verlag, 2007.

[7] Weller, F., Nicklisch F.: Bonding of glass – Latest trends

and research, In: Structures Congress, 2010 ASCE, Or-

lando, Florida, 2010.

[8] Trajanoska, B., Gavriloski, V., Bogatinoski, Z., Gavrilo-

ski. M.: State of the art in research of reinforced structural

glass elements, Mechanical Engineering – Scientific Jour-

nal, vol. 33, 1, pp. 27–32 (2015).

[9] Morgan, T.: Aspects of Structural Glass, Institute of Struc-

tural Engineers, SE Counties Branch, 2010.

[10] Helzel, M., Taylor, I.: Stainless Steel and Glass, Euro Inox,

The European Stainless Steel Development Association,

Brussels, Belgium, 2008.

[11] Bedon, C., Amadio, C.: Stability of flat glass panels under

combined in-plane compression and shear, In book: Chal-

lenging Glass 4 & COST Action TU0905 Final Confer-

ence, Lausanne, Switzerland, 2014.




Received: Jully 19, 2019 UDC: 72.05:57]:[005.961:005.336.1



BIONIC PRINCIPLES OF SPACE OPTIMIZATION APPLIED

IN THE PRODUCT DESIGN PROCESS

Nikola Gerasimovski, Elena Angeleska, Sofija Sidorenko



[email protected]

A b s t r a c t: The main goal of the research presented in this paper is providing multi-functionality and space

optimization of products by exploring and applying modern bionic and design principles. The specific design issue that

needed to be addressed was – design of a multifunctional mountain hiking backpack that allows optimal use of space

and maximal comfort when being used. An ideal solution to this stated problem was accomplished by following several

phases in the process: study of available literature in the areas of multifunctionality, adaptability and product

optimization; analysis of bionic phenomena which were the basic inspiration for creating a modular and compact

design; detailed analysis of ergonomic aspects and anthropometric measurements; recognition of the target group and

market analysis; materials analysis; development of design solutions and selection of the most suitable concept

according to its strongest fulfillment of the given design requirements; elaboration of the final concept and its

evaluation.

Key words: bionics; biologically inspired design; ergonomics; multi-functionality; modularity; optimization of space

БИОНИЧКИ ПРИНЦИПИ ЗА ОПТИМИЗАЦИЈА НА ПРОСТОРОТ

ПРИМЕНЕТИ ВО ПРОЦЕСОТ НА ДИЗАЈНИРАЊЕ

А п с т р а к т: Главна цел на овој труд е преку истражување и примена на современите бионички методи

и принципи на дизајнирање да се изнајдат ефикасни начини за обезбедување мултифункционалност и опти-

мизација на просторот кај производите. Конкретниот дизајнерски проблем за кој беше потребна анализа на

споменатите принципи е креацијата на мултифункционален ранец за планинарење, кој овозможува оптимално

искористување на просторот и максимална удобност при негова употреба. Добивање идеално решение на овој

проблем беше постигнато низ неколку фази: проучување на расположлива литература од областите на мулти-

функционалност, адаптибилност и оптимизација на просторот кај производите; анализа на бионички феномени

кои беа основна инспирација за креирање модуларен и компактен дизајн; детална анализа на ергономските

аспекти и антропометриски мерки; анализа на целната група и пазарот; анализа на материјали; разработка на

идејни решенија и избор на најсоодветен концепт според најсилно задоволување на зададените дизајнерски

барања; разработка на финалниот концепт и негова евалуација.

Клучни зборови: бионика; биолошки инспириран дизајн; ергономија; мултифункционалност; модуларност;

оптимизација на простор

1. INTRODUCTION

Space optimization, modularity and multi-

functionality are complex design principles that al-

low creation of useful products that satisfy various

target group requirements and they could be adjust-

ed for optimal utilization by a wide range of users.

Therefore, these principles provide guidance in the

development of new products with an extended life

cycle in accordance of the fast growing “circular de-

sign model” trend.

Parkinson, Balling and Hedengren [1] define

optimization as the process of determining the best

design and explain the basics of the process. In order

108 N, Gerasimovski, E, Angeleska, S. Sidorenko

Mech. Eng. Sci. J., 37 (1–2), 107–115 (2019)

to optimize, the first step is to create a valid, accu-

rate model of the design problem. Besides a model,

variables which are free to be adjusted and criteria

(objectives and constraints) to be optimized are also

required. The objectives represent goals to be max-

imized or minimized and constraints are limitations.

The design variables of the model are adjusted in

order to achieve objectives and satisfy constraints.

Modularity is another crucial design principle

which aim is to assist creation of flexible products

with low sensitivity to change. These modular pro-

ducts have multiple benefits: reduced production

costs, simplified design updates and reparations, in-

creased product diversity, reduced transportation

time and costs, easier testing etc. Designers and en-

gineers have developed numerous methods for cre-

ating modular products. The Modular Function De-

ployment (MFD) [2] differs from other product

building methods by providing a comprehensive ap-

proach that takes into account the requirements of

all stakeholders in relation to the product develop-

ment. It suggests following 5 steps: defining user re-

quirements, choosing technical solutions, generat-

ing concepts, grading concepts and improvement of

the modules. Creating a modular design helps main-

taining the complexity of the product at a low level,

good deployment of the functions and structure of

the interface.

In the last decade, there is a drastic increase in

the demand for products with added value, that need

to be easy to use, comfortable, flexible to changes

and with modern aesthetics – or in one word, multi-

functional. Multi-functionality can be achieved by

combining many aspects in the design process such

as: following the latest technologies of materials

and production, in-depth analysis of the target

group, creating models of the products, testing their

performance and evaluating results. A well-desig-

ned multifunctional product will increase the feel-

ings of satisfaction and comfort when being used.

The overall comfort is defined as ‘a pleasant state,

physiological, psychological and physical harmony

between a human being and the environment’ [3]

and plays a great role in product design.

All mentioned design principles were recog-

nized as crucial for a successful design of a hiking

backpack and were therefore followed as a guide in

the process of concept generation. They were appli-

ed by using bionic design strategies, detailed study

of the market, ergonomic analysis, study of the lat-

est technologies for backpack production and study

of the user needs.

2. PRINCIPLES OF SPACE OPTIMIZATION

DISCOVERED IN NATURE

Bionic design is a tool that provides functional

principles and forms of nature as an inspiration for

generating concepts and product development.

Bionic methods in the process of product de-

sign are applied by two common approaches:

➢ Process guided by a bionic solution that ins-

pires how to solve an existing design problem.

➢ Process guided by a given design problem for

which a solution is searched in biological sys-

tems.

Versos and Coelho propose the bi-directional

bionic design method [4] and Helms [5] suggests

that in order to find solutions designers must rede-

fine and restructure the problem and functions to

bring them closer to similar problems in nature and

see how they are solved by natural organisms. Al-

ways ask the question ‘how does nature do or

doesn’t do it’.

The bionic method of Versos and Coelho [4]

was adopted for further application in order to study

bionic examples and receive knowledge that can

provide answers that will help achieve the set desig-

ner goals. This was done by the following steps:

1) Defining the designer problem – ‘How to en-

sure maximum utilization of space?’

2) Restructuring the problem in several functi-

ons (Table 1).

3) Asking questions about how those restruc-

tured functions might be solved in nature

(Table 1).

4) Analyzing natural examples (Table 2).

5) Defining solutions and drawing conclusions

(Table 3).

6) Application of the nature inspired solutions

in design concepts.

T a b l e 1

Redefining the design problem (steps 2 and 3)

Decomposition of the

design problem How does nature do it?

Shape and size

transformation

How do living organisms change

their size and shape to adjust to

change of events?

Modular composition

and compact structure

How does nature provide com-

pact structures? What kinds of

elements are natural organisms

composed of?

Multi-functionality How do living organisms achi-

eve multi-functionality?

Bionic principles of space optimization applied in the product design process 109

Маш. инж.науч. спис., 37 (1–2), 107–115 (2019)

T a b l e 2

Finding solutions in nature (step 4)

Shape and size transformation

Pangolins change their shape when they feel threatened

by curling up into a tight, impenetrable ball to protect

their tender undersides.

Armadillos have a similar strategy like pangolins – curling in

a sphere is their defence tactic.

Puffer fish use a reversed method. They maintain a compact

shape and when threatened ‘inflate’ into a virtually inedible

ball several times their normal size.

Modular composition and compact structure

Spirals

Arrangement of sunflower seed

Spiral structure of pineapples

Spiral structure of aloe

Spiral snail shell

Symmetry

Bilateral symmetry of insects

Radial symmetry of flowers

Fractals

Romanesco broccoli – fractals

Fern - fractal pattern

Tessellations

Honeycombs tessellation

of hexagons

Tessellation pattern

of snake and lizard skin

Natural organisms show us how compact complex shapes can

be achieved by a regular repetition of geometric elements.

Natural patterns are formed spontaneously from the forces that

act in the physical world, and at the most basic level these

patterns can often be described using the same mathematical

and physical principles [6].

Multi-functionality

Multi-functionality provides saving resources, material and

space and it is a common principle in nature. For example,

cockroaches and crabs use exoskeletons as a support – it is an

attachment framework for their musculature and at the same

time it has a role in defence from pests and predators.

T a b l e 3

Conclusions from the bionic research (step 5)

Shape and size

transformation

The main volume of the backpack needs to

have elements contained within itself to

enable compact design and small size.

Size enlargement can be achieved by

opening the contained elements one by

one to gradually increase the volume.

Modular

composition and

compact structure

A modular backpack can be created by

simplifying the design to basic geometric

shapes and then attaching them together.

By doing so, the use would be simplified

and the design multifunctional.

Multi-

functionality

Thinking of ways in which the basic mo-

dular and constructive elements of the

backpack can serve more than one func-

tion will help in maximum use of the space

and adding product value.


Mech. Eng. Sci. J., 37 (1–2), 107–115 (2019)

The drawn conclusions from the bionic rese-

arch helped for better understanding of the princi-

ples of space optimization and they were used as de-

sign guides later on in the process.

3. ERGONOMIC ASPECTS OF BACKPACK

DESIGN

A) Ergonomic criteria for designing backpacks

Even though studies of ergonomics of school

backpacks are most common, all of them provide

valuable information about the crucial aspects that

need to be considered in order to design a comfort-

able backpack that won’t deform the users posture.

A study [7] of mountain backpacks was con-

ducted in order to analyze the impact of the back-

pack use on the muscles of the body and the tension

of the user's heart muscles. The study was perfor-

med with 10 male and 10 female subjects, three

most commonly used mountain hiking backpacks,

and modern laboratory techniques (EMG, EKG,

NBM). Results showed that users feel pain when us-

ing the backpacks – in the right shoulder (90%), in

the left shoulder (83.33%) and in the back (60%).

The study, as a conclusion, offers a useful list of rec-

ommendations for designers to follow in order to

create ergonomic backpacks. The backpacks should

be designed according to following:

1) possession of a head restraint for the condi-

tion when the body leans forward;

2) possession of a backrest adjustment system;

3) a sternum strap that serves as a balance bet-

ween the shoulder straps;

4) well-placed shoulder straps that correspond

to the curvature of the shoulder;

5) well-placed hip belt;

6) a design with an outer frame;

7) a back ventilation system;

8) size and shape that corresponds to the size

of the user's body (< 60 litres for small body

sizes and > 60 litres for large body size);

9) backpacks frame made of strong and light-

weight material:

10) strong and lightweight fabric for the back-

pack bag;

11) the backpack bag should be sealed neatly and

tightly to ensure waterproofness.

In addition, it is important to:

1) choose the right size of backpack according

to the body type (this is why backpacks need

to have adjustable straps and belts);

2) properly pack (a person shouldn’t carry

weight larger than 20–25% of his/her body

weight; light items should be packed at the

bottom and the heaviest equipment should be

placed close to the back, above shoulders);

3) choose a backpack with a high-quality back

pad (maximal freedom of movement, even

weight distribution, reduction of pressure on

shoulders).

B) Anthropometric measurements

In the design process, a more extensive anthro-

pometric analysis was necessary in order to provide

customization for users with different physical char-

acteristics.

The measurements were taken from the 95-th

percentile of males and 5-th percentile of females

(Figure 1, Table 4) in order to create a design suita-

ble for 95% of potential users.

Fig. 1. Anthropometric measurements

T a b l e 4

Anthropometric measurements,

95-th and 50-th PCTL male, 5-th PCTL female

(dimensions given in cm)

No. Description 95

male

50

male

5

female

1 Body height 181 171 160

11 Shoulder width 46.2 42 38

5 Hip width 38 32 27

12 Distance – knees to feet 57 53 49

8 Distance – hips to knees 61 56 46.6

3 Shoulder height 62 57 52


Маш. инж.науч. спис., 37 (1–2), 107–115 (2019)

4. DEFINING USER NEEDS AND DESIGN

REQUIREMENTS

According to Cleverhiker [8], the most visited

mountain hiking web site, there is a list with basic

requirements of buyers of mountain backpacks:

1) Price – the backpack should be worth the in-

vestment and last for many years and miles.

2) Weight – a good balance between weight,

comfort and durability is needed (reducing its

weight reduces the overall load hikers carry).

3) Frame – the frame shouldn’t add weight, sim-

ple frames that are comfortable for carrying

up to 16 kg are a good choice.

4) Volume – 40–50 litres pack is sufficient for

fitting all gear, with a need for increasing the

volume for winter trekking due to bulky win-

ter gear.

5) Design – simple and rational design makes the

best backpacks.

6) Material – most backpacks are made from one

of two durable materials: Ripstop Nylon or

Dyneema Composite Fabric (DCF is lighter

and more water resistant, but also more expen-

sive).

7) Fit – comfort is one of the most important fac-

tors, therefore the right dimensions and ad-

justability of the backpack are crucial.

Taking this list into consideration, the designer

requirements are clearly defined. The designed

backpack should be:

• with a simple and practical design focused on

efficiency of the components;

• consisted of modular parts in order to enable

better functionality and easier use;

• multi-functional in order to meet as many user

requirements as possible;

• with an adjustable: back pad, hip belt, shoul-

der straps and sternum strap, in order to pro-

vide maximal ergonomics;

• with an appropriate frame that will distribute

the load forces and reduce the pressure on the

shoulders;

• with a volume of 40 – 50 litres with possibility

for increasing up to 70 litres;

• made out of durable materials.

5. DESIGN OF A COMPACT,

MULTI-FUNCTIONAL MOUNTAIN

HIKING BACKPACK

Taking into consideration all the gathered in-

formation and the defined designer requirements,

the next step was generating ideas and developing

the design of the backpack.

a) Generating concepts

Several concept designs were elaborated

through sketching (Figures 2 – 4) and then finally

compared and graded according to the most im-

portant criteria: comfort, ergonomics, compact de-

sign, multi-functionality, modularity, capacity, ma-

terials and design. The best concept was selected for

further development (Figure 5).

Fig. 2. Concept 1

Fig. 3. Concept 2


Mech. Eng. Sci. J., 37 (1–2), 107–115 (2019)

Fig. 4. Concept 3

Fig. 5. Concept evaluation using the spider mesh diagram

b) Further development of the selected concept

The final design is a backpack built out of 5 independ-

ent modules which have individual functions (Figure 6;

Table 5). When joined together, the modules obtain the

final purpose of the product. As the examples found in

nature, the modular design enables simplified increasing

in size, form and function and easy adjustment to differ-

ent external conditions. Because the parts are independ-

ent they can be produced in different locations and there-

fore possibly reduce the overall production cost com-

pared to traditional production processes. In addition, any

issues with one component can be solved by its replace-

ment instead of replacing the whole product which pro-

longs the life expectancy of the product.

Fig. 6. Exploded view of the backpack modules

0

2

4Comfort

Ergonomics

Compact…

Multi-…

Modularity

Capacity

Materials

Design

Concept 1 Concept 2 Concept 3


Маш. инж.науч. спис., 37 (1–2), 107–115 (2019)

T a b l e 5

Basic modules of the designed backpack explained

No. Description

1 External frame with ergonomic back plate

2 Shoulder straps

3 Backpack

4 Lumbar support belt

5 Exoskeleton

The 5 independent modules are:

1) External frame with ergonomic back plate

(Figure 7)

The outer frame is designed to detach the back-

pack from the body. It has an ergonomic design fol-

lowing the natural curvature of the spine. It is cov-

ered with a soft sponge and 3D air mesh fabric for

air circulation and comfort. Airflow and air contact

systems prevent the body from sweating. This frame

is a base, with guides on which different types of

backpacks (with their own external frames) can be

attached.

2) Shoulder straps (Figure 8)

The shoulder straps are also designed as a sep-

arate component that is attachable to the external

frame by straps and Velcro. There are 5 levels of

height adjustment for the shoulder straps so that

they can be used by different types of users without

ruining the ergonomic features. The shoulder straps

contain a sternum strap for additional fixation and

security, with incorporated plastic slider compo-

nents for obtaining of length adjustability.

3) Backpack

Inspired by the ways in which natural organ-

isms have perfected their adjustment to the external

factors by adapting their size and led by the user re-

quirements for maximum use of volume and multi-

functionality, the backpack was designed with an

adjustable volume. Like the pangolins or armadil-

los, this backpack unfolds to release additional vol-

ume. The basic part has a size of 40 liters, built with

a bottom plate made of cross-linked polyethylene

for maximum stiffness and damage protection (Fig-

ure 9). When a larger size is needed, the bottom zip-

per opens to release additional 15 liters (Figure 10).

In order to obtain extra 20 liters, there is an internal

mechanism for vertical extension which serves for

lifting the top and achieving the final volume of 75

liters (Figure 11). The backpack has an outer frame

for attaching to the basic frame with the back plate.

In addition, the design of the backpack frame allows

vertical sliding of 5–6 cm when the hiker is moving

and this sliding helps to reduce the load forces and

weight on the shoulders by 60%.

4) Lumbar support belt (Figure 12)

This belt is intended to be used when the back-

pack is heavily loaded. It can be attached to the ex-

ternal frame and when used it changes the gravity of

the whole backpack, and therefore, it also changes

the load forces on the body. It has been calculated

that when using a lumber support belt of over 80 cm,

the load on the body is reduced by 15%.

5) Exoskeleton

The exoskeleton is based on a bionic principle

and it has a purpose to transfer the entire weight

from the shoulders and hips to the shoes. It also sup-

ports the body and gives it extra strength. Natural

exoskeletons (like the ones found on insects and

crabs) are an external body cover for some inverte-

brates which provide support and protection. In this

case, the exoskeleton is used to increase the physical

capabilities of the backpack users and ergonomic

features of the backpack itself. The exoskeleton is

simple to mount on the external frame by screwing

it to the shaft (Figure 13). The mechanism is cus-

tomizable for each user. There is an option for hor-

izontal adjustment of the upper part and 2 points of

vertical adjustments among the legs.

The whole exoskeleton can be fastened to the

legs in 2 spots and fastened to the shoes in 1 spot. It

is meant to be attached on the outside of the legs and

it follows all the natural functions of the legs –

movement, kneeling, running etc. The exoskeleton

can be folded when not being used (Figure 14).

Figs. 7–8. Back view of the basic external frame

with shoulder straps and backpack attached

Fig. 9. Backpack 40 liters Fig. 10. Backpack 55 liters


Mech. Eng. Sci. J., 37 (1–2), 107–115 (2019)

Fig. 11. Backpack 75 liters

Fig. 12. Lumbar support belt

Fig. 13. Exploded view of the exoskeleton components and

the way they are attached to the basic external frame

Fig. 14. Folded exoskeleton

Multi-functionality of the design is also achi-

eved by additional functions to some of the compo-

nents. There are solar panels installed on the front

side and batteries that provide energy for charging

electronic devices or LED lamps (Figure 15).

Another key feature is the special designed

structure of the exoskeleton, that could be easily

transformed to be used as a base construction for a

one person tent (Figures 16 and 17).

By thinking about additional features of the

components the value of the design is increased, the

backpack is brought closer to the needs of the target

users. This means they would be willing to invest in

it and used for many years.

Fig. 15. Solar panels installed at the front of the backpack

Fig.16. Use of the exoskeleton as a tent construction


Маш. инж.науч. спис., 37 (1–2), 107–115 (2019)

Fig. 17. Use of the exoskeleton as a tent construction

6. CONCLUSIONS

The main goal of this research was to suggest

design methods for creating products that are com-

pact, modular, multi-functional and have adjustable

shape and size. Creating such products is in favor of

the circular design economy which challenges de-

signers to think about maintaining a loop life cycle

of items by: extending their utilization period, mak-

ing them multi-functional, easier for manufacturing,

suitable for reuse and repair etc.

For successful achievement of the main goal,

an in-depth analysis of bionic principles related with

the mentioned characteristics was done. Bionics as

an interdisciplinary field offers inexhaustible inspi-

ration for solving problems in many different indus-

try branches.

The design methods were used to propose a

concept for a mountain hiking backpack with maxi-

mum utilization of its volume in order to fit as much

equipment and tools as possible and enable carrying

larger weights without causing discomfort and pain

to the user. Seeking inspiration in nature, as well as

analyzing the ergonomic requirements, user prefer-

ences and latest technologies were important for of-

fering a backpack that has improved functional and

ergonomic features. The designed backpack takes

the users experience to the next level, offering: ad-

justable volume; independent modular components

that can be used and combined together according

to needs; system for reduction of the load forces on

the body, therefore reducing pain in the back and

shoulders; additional features including ecological

production of electric energy sufficient for charging

of electronic devices and using a part of the main

structure for building a tent.

The conclusions drawn from this research can

be used as an example or starting point for other de-

signers that seek a way to provide multi-functional-

ity and space optimization.

This paper also emphasises the importance of

conducting thorough researches on all aspects rele-

vant to the given problem and applying all available

technological and scientific achievements in order

to reach the best result.

REFERENCES

[1] Parkinson, A. R., Balling, R. J., Hedengren, J. D.: Optimi-

zation Methods for Engineering Design: Applications and

theory, Brigham Young University, 2013.

[2] Ericsson, A., Erixon, G.: Controlling Design Variations:

Modular Product Platforms, Modular management AB

and Society of Manufacturing Engineers, 1999.

[3] Fourt, Lyman; Hollies, Norman: Clothing: Comfort and

Function (Fiber Science), Dekker (Marcel), 1971.

[4] Coelho, D. A., Versos, C. A. M.: A comparative analysis

of six bionic design methods, International Journal of De-

sign Engineering, 4 (2), 114–131 (2011).

[5] Helms, M., Vattam, S. S., Goel, A.: Biologically inspired

design: process and products, Design Studies, Vol. 30, No.

5, pp. 606–622 (2009).

[6] Ball, P.: Patterns in Nature: Why the Natural World Looks

the Way It Does, University of Chicago Press, 2016.

https://www.amazon.com/Patterns-Nature-Natural-World

-Looks/dp/022633242X

[7] Retnari Dian, M., Velahyati, A., Hartati, H.: Desain Back-

pack Berdasarkan Analisis Biomekanika dengan Pendeka-

tan QFD dan TRIZ untuk Pendaki Wanita, Hasil Penelitian

Fakultas Teknik, Grup Teknik Mesin, Universitas Hasan-

uddin, Vol. 5, pp. 1–12 (2011),

[8] Cleverhiker: 10 Best Lightweight Backpacks of 2019,

(2019), www.https://cleverhiker.com/

https://www.researchgate.net/profile/Denis_Coelho

https://www.researchgate.net/journal/1751-5874_International_Journal_of_Design_Engineering

https://www.researchgate.net/journal/1751-5874_International_Journal_of_Design_Engineering

https://www.amazon.com/Patterns-Nature-Natural-World

https://www.google.com/search?rlz=1C1GCEA_enMK760MK760&q=D.+Retnari,+A.+Velahyati,+and+Hartati,+(2011),+Desain+Backpack+Berdasarkan+Analisis+Biomekanika+dengan+Pendekatan+QFD+dan+TRIZ+untuk+Pendaki+Wanita,+Hasil+Penelitian+Fakultas+Teknik,+Grup+Teknik+Mesin,+universitas+Hasanuddin,+Vol.+5,+pp.+1-12&sa=X&ved=0ahUKEwim1qjbqovhAhVsQRUIHW0bAREQgwMIKw


CODEN: MINSC5 ISSN 1857–5293

e: ISSN 1857–9191

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