Design Engineering designsurilshah.weebly.com/uploads/1/1/4/6/11462120/domm... · 11-08-2015 4...

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ME 311: Dynamics of Machines and

Mechanisms

L3: Design Process

Suril V. Shah

IIT Jodhpur

Presentation Layout

• Engineering Design

• Engineering Design Process

• A design case study

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• The term design can encompass activities like

• Engineering design embodies all of the above activities as well as many others

Newest look

Design

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Impressive architecture Engineering bike

https://images.google.com/

Rocker-bogie

Engineering design

• Process of applying various techniques and

scientific principles for the purpose of defining a

device, a process or system in sufficient detail to permit realization.

• Design can be

– Involve a trivial problem or problem of great importance

– Mathematical or non mathematical

– Simple or enormously complex

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Creativity

• Creativity is in the backbone of design process

Courage to create

• Creativity coupled with scientific

principles lead to successful design

• Much of engineering has little to do with creativity in its fullest sense.

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Creativity and Engineers

• Many engineers prefer the realms of analysis, testing and product or process refinement.

• Many others find their satisfaction in management or business roles

(Are we trapped in the above two?)

• But only few enter into creative enterprise

We need more creator than the workforce for

developed nations6

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Some creativity

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Let us instigate our creativity

How many times do we challenge our mind think creatively?

8https://images.google.com/

Let us further challenge ourselves


Engineering Design Process

• Design is a universal constituent of engineering practice

• Textbook problems: given A, B, C, and D, find E

• Real-life problems are almost never so structured but are ill-defined and incomplete.

• Leads to "blank paper syndrome”.

• Challenge is structuring the unstructured

problem

Idea is to carefully define the problem using an engineering approach

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WHAT CAN BE THE STEPS OF

DESIGN PROCESS?

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Design process

• Goal

• Background research

• Constraints

• Divide into sub problems

• analysis

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1. Identification of need

• This step is often done for you by someone, boss or client, saying "What we need is ... “

• Typically this statement will be brief and lacking in detail.

• It will fall far short of providing you with a structured problem statement.

• For example, the problem statement might be "We need a better lawn mower."

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2. Background research

• The most important phase, and unfortunately often the most neglected.

• Has similar problem solved before?

• There is no point in reinventing the wheel.

• Gathering background information on the relevant aspects of the problem

• Look the patent literature and technical publications in the subject area

• Bench marking

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3. Goal statement

• Recast that problem into

a more coherent goal statement

• It should be concise, be general, and be uncoloredby any term which predict a solution.

• Use functional visualization to avoid unnecessarily limiting your creativity!

• Original statement of need was "Design a Better Lawn Mower.”

Wiser designer will restate the goal as "Design a Means to Shorten Grass.“ 15


4. Performance specifications

• It define what the system must do

• Enemy of design is the absence of specification

• A sample set of performance specifications for our "grass shortener"

• Test finished design can be tested for compliance with the specifications

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5. Ideation and invention

(Creative process)

• Most satisfying but most difficult phase

• Full of fun and frustration

• Do not try to judge the quality of your ideas

• Define the action verb in the problem statement, and then list as many synonyms .

• Problem statement: Move this object from point A to point B. The action verb is "move." Some synonyms are push, pull, slip, slide, shove, throw, eject, jump, spill.

• Try to circumvent largest barrier to creativity that is fear of ridicule

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The creative process

• Idea generation

• Brainstorming

• Frustration

• Incubation

• Eureka


5. Ideation and invention

(Creative process)

• At some point your mental well may go dry.

• Try to involve in other tasks

• Let idea to grow in your subconscious mind

• Solution

18https://images.google.com/https://images.google.com/


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Requirements for creative insight

• Fascination with a problem.

• Saturation with the facts, technical ideas,

data, and the background of the problem.

• A period of reorganization.

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6. Analysis

• At this stage, you have structured the problem,

• Develop numerical models

• Apply sophisticated analysis techniques to examine the performance of the design

• Further iteration will be required due to problems discovered in analysis.

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Caution: Iterative process

• Design is an iterative process in which progress is made haltingly, two steps forward and one step back.

• It is inherently circular.

• Your apparently great idea, upon analysis, turns out to violate the law of thermodynamics, you can return to the ideation step and get a better idea!

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7. Selection

• Analysis indicates that you have

some potentially viable designs

• Best one available must be selected for detailed design, prototyping, and testing.

• Selection involves a comparative analysis of the available design solutions.

• A decision matrix sometimes helps to identify the best solution by forcing you to consider a variety of factors in a systematic way.

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Decision Matrix

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8. Detailed design

• Includes the creation of a complete set of assembly and detail drawings or computer-aided design of parts

• Each drawing must specify all the dimensions and the material specifications.

• From these drawings a prototype test model must be constructed for physical testing.

• Most likely the tests will discover more flaws, requiring further iteration.

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9. Prototyping and Testing

• A mathematical model can never be complete and accurate a representation of the actual system

• One cannot be sure of the correctness or viability of any design until it is built and tested.

• Prototypes can take many forms, from working scale models to full-size, but simplified, representations of the concept.


10. Production

• With enough time, money, and perseverance, the design is ready for production.

• Manufacture of a single final version of the design

• More likely, making thousands or even millions of your widget.

• The embarrassment of finding flaws in your design should inspire you to use the greatest care in the earlier steps of the design process

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Human factor engineering

(Ergonomics)• Study of the human machine

interaction

• Machines are designed to be used by humans.

• Design of devices and physical working conditions with the capacities and requirements of the worker.

• Design devices to "fit the man" rather than expect the man to adapt to fit the machine.

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Engineering report

• Communication of your ideas and results is a very important aspect of engineering.

• When your design is done, it is usually necessary to present the results to your client, peers, or employer.

• The usual form of presentation is a formal engineering report.

• You may be the cleverest person in the world, but no one will know that if you cannot communicate your ideas clearly and concisely.

• Thus, it is very important for the engineering students to develop their communication skills.

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EARTH-BASED PROTOTYPE OF

SPACE ROBOT

Design case study

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Problem statement

• Design of an earth based space robot

simulator

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Background research

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Maryland University

West Pomeranian University of Technology National Technical University of Athens

Tokyo University

Harbin Institute of Technology,

MIT

Goal

Design of a planar earth-based prototype of

space robot for simulating reactionless

manipulation

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Performance specification

• Imitate gravity free environment

• Base should be able to carry pay load of 2-3 kg

• Arms should be able to carry 0.1-0.3 Kg

• Low cost, cost less < 10 lacs

• Modular Compact in house set-up

• Help us in testing algorithms

– Reactionless manipulation

– Vision-based control

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Ideation

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West Pomeranian University of Technology, Poland

Mechanical Design

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Schematic of Earth-based

experimental set up

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Analysis

• Selection of actuator

• Modelling and torque estimation

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Actuator selection

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Controller

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Pneumatics

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Production

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THANK YOU

Acknowledgements:

Space Robot design and experimentations: Francis James , P. Mithun

Shubham, Punneeth, V. V. Anuarg, Nandini, Akash Kant

Hoping to see some of you enter in creative enterprise

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