An Introduction to the World of Motion Control

8/10/2019 An Introduction to the World of Motion Control

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An Introduction to the World of

Motion Control

Prepared by:Tamir Al Balkhi, Priyanka Daniel & Hiren Mistry

Class : PROC TECH 3SD3

Date :November 14, 2014


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Table of Contents

Title Page

1. Abstract...3

2. Introduction.....4

3. History.....5

4. Applications of Motion Control........5

4.1 Robotics and their manufacturing applications.... 5

4.2 Film production, gaming and Photography......6

4.3 CNC Machining.......6

5. Motion Control Architecture......7

5.1 Controller.. ....7

5.2 Driver...... 8

5.3 Motor ...8

5.4 Feedback loops and Devices..8

6. Machine Learning and Future uses.....9

7. Conclusion....10

References..11

Questions12

Figures Page

Figure 1: Typical Motion Control System3

Figure 2: 20thCentury assembly line.....4

Figure 3: Line of Robots manufacturing cars5

Figure 4: Motion controlled robot used in filming5

Figure 5: Microcontroller.8

Figure 6: Anatomy of a Brushed DC Motor8

Figure 7: System Block Diagram..9


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1.Abstract

The guide to the body of automation specifies motion control as one of its topics of interest. In this

paper, an introduction of motion control will be presented. The history, components, application,

use of machine learning and future uses will all be outlined. Motion control is a field of automation

in which mechanical machines are controlled using a controller, drive and motor. The systems thatcan be controlled vary and can use pneumatic, hydraulic or electromechanical actuation technology.

The controller being the brain sends signals via I/O commands to control the motor using the drive.

The feedback elements in a motion control system are the final part of the loop that loops back to

the controller. It sends information about the output and is used as a check to ensure that the motor

or load measured reaches the position or velocity given to it by the system. The main uses of a

motion control system are to analyze and control velocity and position, pressure and force and

assembly lines among other industries. Furthermore, network protocols such as PROFIBUS,

DeviceNet, Smart Distributed Systems and EtherCAT to name a few are the communication portals

through which the motion control system utilizes for communication. Robots are used everywhere

in the industry and have become essential to the manufacturing process. There are countless

factories filled with thousands of robots and only a few operators. The rate of automating processes

in todays society is increasing at an alarming rate. The precision and effectiveness of products

created by these robots can allow companies to withstand the demand of the populous. From

simple CNC machining to complex autonomous robotic control, motion control has advanced using

more advanced controllers, and feedback loops, as well as more efficient drivers to send signals.

Moreover, with the progression of machine learning and more powerful algorithms and controller

parts for the system to use, a robot can learn faster than it ever could twenty years ago. This

development in technology allows for the robot to be more autonomous and have bigger impact on

daily lives in many fields of technology, education, science, entertainment and safety. The faster and

more efficient CPUs have allowed the autonomous robot to analyze information in higher gigaflops

in order to make it a smoother machine.


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Figure 1: Typical Motion Control System

2. Introduction

Motion control is a subsidiary in the field of automation in which mechanical machines are

controlled to serve an automated purpose. The systems that can be controlled vary and can use

pneumatic, hydraulic or electromechanical actuation technology. Motion control systems are

complex and are comprised of multiple parts that include motion controller, drive or amplifier,actuator and feedback elements. A typical

system is shown in Figure 1.

The motion controller is the brain of a

motion control system. It is used specifically

for controlling motion and uses I/O

commands that are specific to its use. The

motion paths are generated by using set

points to control the desired output which

react to any changes applied to the outside of

the system. Most motion controllers are PC

based and come equipped with a graphical user interface which allows simple and advanced

features to be easily configurable through an operator's screen.

It varies to how complex it can be, ranging from either as simple as an ON/OFF switch or a

computer that can control multiple motion control devices. The features that it also possesses make

it more expensive to purchase.

The drive or amplifier converts the control signal given from the motion controller into a higher

power signal that gets sent to the motor to drive the output. The drive originally started off as a

single quadrant model which would simply provide a link between the controller and the motor

however, as technology advanced the drive can now be four quadrants with abilities to both drive

the motor and regenerate it in both the forward and backward direction.

An actuator is the output of the motion control system which is responsible for moving or

controlling a mechanism in the system. It varies in the type of device, but typical ones used are

hydraulic pump, linear conveyors, electric motors and air cylinders.

The feedback elements in a motion control system are the final part of the loop that loops back to

the controller. It sends information about the output and is used as a check to ensure that the motor

or load measured reaches the position or velocity given to it by the system. Feedback elements also

vary and devices such as optical encoders, resolvers and Hall effects are just a couple of feedback

devices that relay the position or velocity of the output back to the motion controller. This allows

operators to analyze information at different stages in the motion control system.


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3. History

The beginning of the industrial revolution dates back into the 1760's but motion control didn't

startup until the early 1800's. The need for machinery to automate repetitive tasks was in demand

and the early automation took form as crude motors with belt and pulley drive trains. These motors

were purely mechanical and powered using a large water wheel or steam engine. It wasn't until the1870's where the DC generator and public electricity gave way to inventions that used electrical

power to drive a motor and create electromechanical systems. By 1927, Harold black and

discovered the concept of negative feedback in amplifiers and soon after in the 1930's the first

pneumatic motion control products were developed. Throughout the 50's 60's and 70's, different

components of a motion control system were being used and developed primarily for space flight

and war. These advances helped mold the idea of motion control and by the late 1990's, motion

control took a huge advancement by introducing digital communications via serial networks and

network protocols such as PROFIBUS, DeviceNet and Smart Distributed Systems took over the

automation market.

Today, in the 20th century, motion control

systems are increasingly complex, and there are

many choices as to what you want when creating

the system. Ethernet connectivity, HMI's (human

machine interface) and PC/Software integration

have become the norm in designing a system.

Designers of the systems are demanding more

open standard solutions which mean multiple

devices can be used in conjunction with one

another without having any limitations. That

means any controller, any motor, any feedback

element, any network, and any environment could

be used to create a system that caters exactly to an operator's needs. In present day, industries

such as semiconductor production, printing, packaging, and assembly are just a few that use these

types of systems.

4.Applications of Motion Control

There are countless uses of motion control in today's world. Motion control is a broad term and has

different meanings to various industries. The main uses are velocity and position control, pressure

and force control, assembly lines and the film industry.

4.1 Robotics and their manufacturing applications

For a product to be assembled successfully, it is essential to move the right parts to the right place

and orientation at the right time. The technology of motion control with the help of robots has made

that happen. Robots are used everywhere in the industry and have become essential to the

manufacturing process. There are million factory robots in the world, and this rate keeps increasing

Figure 2: 20th Century Assembly Line


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every year. Since robots work at higher speeds and higher precision, over the years, they have

drastically decreased cost of labour and increased production due to which yesterday's luxury

items have become today's disposable's. Most robots require just a robot arm to do the job. Each

arm typically has several joints, servo motors and stepper motors to power the joints. The user can

input specific commands using an HMI that then communicated with the robot. Most assembly

lines' uses replicated motion control meaning once the information is fed to the robot theprocedure repeats itself for every single product. Assembly line's that manufacture different kinds

of products have to be programmed. Various motion controls such as speed, positioning, rotating

motion, pressure and force control are used for several products from manufacturing and

packaging orange juice to an automobile.

4.2 Film Production, Gaming and Photography

Motion control has great uses in the film production industry. Almost every movie that you have

watched may have made use motion control. The most commonly used the precise and repeatable

control of a speed and position of the camera. There is usually a camera that sits on the end of an

arm containing about 12 degrees of freedom that can swing, lift, extend, tilt at an angle, roll or movealong a track. Some camera controls include closing the shutter, focusing and zooming. The Milo

motion control rig is a true visual effects tool that is used in every filming center of the world. In the

movie Dr. Do Little (1998), several shots of Eddie Murphy and the animals were shot at different

times and combined. It would have been too dangerous to lose an actor or make the different kinds

of animal's act together in the same scene otherwise. Sometimes, a collective amount of people may

be filmed to represent a busy street. This cuts costs and labour of hiring and training several actors.

The same applied to gaming and photography. For Example, the PlayStation Move motion

controller is a combination of motion sensors, dynamic colour changing spheres and vibration

feedback.

Figure 3: Line of Robots manufacturing cars Figure 4: Motion controlled robot used in filming

4.3 CNC Machining

CNC (Computer Numerical Control) method is the process used in the manufacturing sector which

involves the use of computer's to control machines tools. This technology reduces cycle time,

improves surface finish, drills faster and extends machine life. The tools that can be controlled in


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this manner are vertical mills, center lathes, shaping machines that are usually operated by a

trained engineer. This machine may seem like a normal PC controlled machine, but the unique

software and control console of the computer is what makes a CNC machine distinct. A customized

computer program is made for an object and programmed with CNC machining language that

control's various features like the feed rate, coordination and location speed. This process is usually

used in the manufacturing of metal and plastic parts. The objects produced are more precise thanthe one's produced by a regular machine. These complex parts would have been nearly impossible

to produce otherwise. CNC machines cut manufacturing costs by lowering upgrade costs and

replacing skilled engineers with computers. Several products like aerospace and military

equipment, in which precision is never a compromise, are manufactured using CNC machining

technology.

5. Motion Control Architecture

Advancements in motion control technology usually are focused on improving accuracy, speed and

efficiency of the system. While these advances are important, changes in the architecture of motion

control are just as important. In the past ten years, motion control architecture has been developed

to offer reduced wiring, improved reliability and complex computer controlled systems. A general

motion control system is comprised of a controller, an actuator and a motor followed by a feedback

loop system. Other components include gears, shafts, joints, etc. The controller handles the machine

interfacing and sends signal's based on the algorithms. Drivers and actuators are meant to drive the

motor according to the controller's reference signals; the motor then sends the feedback back to the

controller.

5.1 Controller

The controller sends signals to the drive that powers the motor, the motor then sends a feedback

loop to the controller. The controller is also responsible for analyzing and correcting errors in the

feedback signals. Controllers can be simple as an ON/OFF switch to an operator controlled dial.

Complex controllers are computer controlled and are usually responsible for a set of servo's

containing several inputs and outputs. Physical forms of controllers are Microcontrollers, PLC's and

Motion controllers which are chosen based on cost, performance and ease of use. A microcontroller

is a small computer which can be configured by an experienced programmer. These devices are

used for their low costs but can be quite difficult to close loops. Loops are closed with the help of

drives and amplifiers depending on inputs like sensor's and switches going into the controller.

PLC's are programmable logic controllers which were first used to troubleshoot sequential relay

circuits and eliminate the mess of wires. Their processor and memory can be programmed with

commands; these commands can be saved and executed. Inputs and outputs can be added moreefficiently than a microcontroller as needed. Features like high-speed counters and timers are

available. PLCs cost more than microcontrollers, have limited lifetimes but are more efficient.

Motion controllers are usually PC-based to allow graphical user interface and are specifically

designed to control motion. They cost more than PLCs and microcontrollers due to added features

like ease to tuning, computation, sensing and other functions.


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5.2 Driver

A drive, also known as an amplifier translates low energy signals referenced from the controller

into high energy power signals to the motor. This link in between the controller and the motor first

started as single quadrant models just powered brushed motors. Later the drives were able to

power a regenerate a motor in both directions. Current drives are meant for more features likeencoders, resolvers, tachometers, limit switches and various sensors to be added to it. As

mentioned, earlier drivers are also responsible in closing feedback loops like velocity and position

loops. They also take charge of many complex control functions that can be controller's by a

controller.

5.3 Motor

A motor converts the current and voltage that comes from the driver into mechanical motion.

Motors can be of rotatory or linear types. Brushed motors mentioned earlier are single phase

motors which are very easy to set up and are used to drive single phase loads. This kind of motor is

the most common of its kind and directs the current into the correct coils at the correct time. Linearactuators are actuators causes' motion in a straight line instead of the conventional circular motion.

They move the liner shaft in and out with the help of rotary motors. Audio speakers use voice coils

that have a linear motion and limited 0.5'' of travel. These motors require a high-performance drive.

Three phase motors has higher power density, better heat dissipation and require less

maintenance. This type of motor uses alternating current to power large motors that are used for

heavy loads. Linear motors are similar in configuration to a rotary motor and are used in

applications where speed and accuracy is required.

Figure 5: Microcontroller Figure 6: Anatomy of a Brushed DC Motor

5.4 Feedback Loops and Devices

To ensure that the motor or load reaches the commanded position or velocity feedback loops are

used. There are used to determine how much current is needed to power a motor based on present

position and velocity. Absolute and Relative are two types of feedback loops. Absolute loops

provide a specific position and range upon powering up the motor while relative feedback loops


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provide incremental position updates. An absolute feedback is used in conjunction with a relative

feedback to know the motor's initial position. The incremental feedback then provides the position

over a range of motion. Some of the most commonly used feedback devices are hall sensors and

resolvers. Hall sensors are transducers used for computational control needed for higher velocities.

They are commonly used to time the speed of wheels and shafts. Resolvers are rotary transformers

that are used in a high temperature and high vibration environment.

6. Machine Learning and Future Uses

Machine learning is a scientific discipline that uses algorithms to improve the situation from

collected data whether it is real time or saved data. These algorithms aid in the improvement of

robotics as they can learn to adapt to situations with little human aid or contact to decipher

problems when faced with obstructions or unperceived decisions. The use of machine learning can

be found in complex CNC machines, autonomous robots in military, transport, underwater

expedition, space travel and many other relatable topics and industry. Utilizing the global

coordinate system, a machine can analyze its surrounding location and its orientation related to

those positions to keep it aligned to the horizontal plane. The usefulness of this analysis can be

utilized in underwater expeditions, where autonomous robots need to stay level while sinking to

the ocean floor for analysis. In many aspects of life, machine learning has revolutionized computers

and robotics. The early 90s saw a trend of machine learning application in data mining, text and

language learning that aided robots in simple tasks such as the IBM computer Watson that can

interpret the vocal questions in jeopardy and answer them successfully. Moving forward with

machine learning, developers and engineers have found themselves implementing pattern

recognizing algorithms that learn from experience and improve the accuracy of the robots actions.

These algorithms can be transferred onto am industrial setting where multiple CNCs learn and

create more efficient cuts in their process. In addition, a process where machine vision is required

to control movements of a robot or a process, learns from its past iterations and becomes moreeffective in doing its pre-programmed tasks is also a common application. In a Texas University

based experiment robots are used to mimic children who suffer from autism, to better understand

their motor skills and social interaction. Using the data

collected they later help the children improve the motor skills

that the researchers found to be slower than normal. The

applications of machine learning are endless and with their

introduction to robotics and especially in motion control, the

possibility to more humanoid-like robots is a close reality.

Figure 7: System Block Diagram


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7. Conclusion

This paper presents the basic information of motion control. The history, what motion control is

made up of, applications, machine learning and future uses are all outlined. Although, motion

control is comprised of a controller, driver and motor the advancements in technology have made

all the parts work more efficiently and effectively together. Utilizing robotics in many differentfields, such as industrial settings, gaming and film production have enabled motion control to

improve and become more robust. With different technologies emerging the applications for

motion control, are endless as we strive for a more optimized and autonomous robotics.


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References

1. Fundamentals of Motion Control. National Instruments. Web. 2014.

2. Garus, Jerzy. "Fuzzy Control of Undersea Robotic Vehicle in Plane Motion."Fuzzy Control of

Undersea Robotic Vehicle in Plane Motion. ACM, 02 June 2008. Web. 10 Oct. 2014.

3.

Hatori, Hideo, and Masami Marubayashi. "Application Examples of Motion Control Systems."

Application Examples of Motion Control System (n.d.): n. pag. Web. 13 Nov. 2014.

.

4.

More about CNC Machining. ThomasNet . Web. Nov 14, 2014

5.

Monniaux, David. "Welcome to Home." Welcome to Home. Pascaline, 1 Jan. 2008. Web. 14

Nov. 2014.

6.

Pinto, Jim. "Robotics Technology Trends." : The Future of Robots by Jim Pinto. Automation

Inc., 20 Apr. 2013. Web. 22 Oct. 2014.

7.

Trevathan, Vernon L.A Guide to the Automation Body of Knowledge,. 2nd ed. N.p.: 2006, n.d.

Print.

8.

"University Outreach." History of Motion Control. N.p., n.d. Web. 14 Nov. 2014.

.
http://www.ni.com/white-paper/3367/en/#toc1(componentshttp://www.thomasnet.com/about/cnc-machining-45330503.htmlhttp://www.thomasnet.com/about/cnc-machining-45330503.htmlhttp://www.ni.com/white-paper/3367/en/#toc1(components


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Questions

1. What is CNC machining?

2. Name the 4 parts of a motor control system?

3. what function does the driver have

4.

What is machine learning?

An Introduction to the World of Motion Control

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