Position control for linear motion servo system via nominal characteristic trajectory following controller

UNIVERSITI TUN HUSSIEN ONN MALAYSIA

BORANG PENGESAHAN STATUS TESIS •

JUDUL: POSITION CONTROL FOR LINEAR MOTION SERVO SYSTEM VIA NOMINAL CHARACTERISTIC TRAJECTORY FOLLOWING CONTROLLER

SESI PENGAJ1AN: 2008/2009

Saya: NOOR HISHAM BIN JALANI (740204-01-5049) (HURUF BESAR)

mengak.1l membenarkan tesis (PSM/Smjana/Doktor Falsafah)* ini disimpan di Perpustakaan dengan syarat-syarat kegunaan seperti berikut:

I. Tesis adalah hakmilik Universiti Tun Hussien

ann

Malaysia.

2. Perpustakaan dibenarkan membuat salinan untuk tujuan pengajian sahaja.

3. Perpustakaan dibenarkan membuat salinan tesis ini sebagai bahan pertukaran antara institusi pengajian tinggi.

4. **Sila tandakan(.J')

D

D

m

SULIT TERHAD TIDAK TERHAD (TANDATANGAN PENULIS) Alamat Tetap:

NO.9, JALAN PERDANA 24 TAMAN BUKIT PERDANA 83000 BATU PAHAT JOHOR DARUL T AKZIM

Tarikh: II Nov ~o~

(Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia seperti yang termaktub di dalam AKT A RAHSIA RASMI 1972)

(Mengandungi maklumat TERHAD yang telah ditentukan oleh organisasilbadan di mana penyelidikan dijalankan)

Disahkan oleh

(TANDA

DR. HJ. JIW A BIN ABDULLAH

J

EN. JAMALUDIN BIN JALANI Tarikh: 13 NoV :)..Ob'f.

CAT A TAN:

*

Potong yang tidak berkenaan.

**

Jika tesis ini SULIT at au TERHAD, sila lampirkan surat daripada pihak

berl-:uasalorganisasi berkenaan dengan menyatakan sekali sebab dan tempoh tesis ini perlu dikelaskan sebagai SULIT atau TERHAD.

POSITION CONTROL FOR LINEAR MOTION SERVO SYSTEM VIA

NOMINAL CHARACTERISTIC TRAJECTORY FOLLOWING CONTROLLER

NOOR HISHAM BIN JALANI

A project report is submitted as a partial fulfilment

of the requirements for the award of the

Master's Degree in Electrical Engineering

Faculty of Electrical and Electronics Engineering

University Tun Hussein Onn Malaysia

"We declared that we read this project and in our point of view this project is

qualified in terms of scope and quality for purpose of awarding the

Master's Degree in Electrical Engineering."

Signature

Supervisor I

Date

Signature

Supervisor II

Date

... (J.

...

~

... .

DR. HJ. JIWA BIN ABDULLAH

\ 3 Nov

:J,-O-oq,

~H

MR. JAMALUDDIN BIN JALANI

....

\}.~~

..

~

... .

"I declare that this project is the result of my own work except the ideas and

references which 1 have clarified their sources."

Signature

Name of Writer

Date

...

~

... .

'v

NOOR HISHAM BIN JALANI

"\\ NOV ~

...

\.

ACKNOWLEDGEMENT

First of all, all thanks are due to Allah.

I would like to thank Dr. Jiwa Abdullah and Mr. Jamaludin Jalani for their

extraordinary patience and their enduring optimism. I admire their knowledge,

intelligence, and patience. I do appreciate their dedicated guidance, suggestion,

critical comments and warm supports. I am blessed and honoured to be their student.

I would like to acknowledge the Public Service Department of Malaysia (JP A) for

sponsoring my master degree study.

I also would like to thank friends for their helpful suggestions.

Special thanks are due to my wife for her extreme patience. She has been and

continues to be a constant source of inspiration, motivation, and strength.

Finally, my sincere gratitude goes to my parents for their love, endless

encouragement and support over the years. They are responsible for there being

PUBLICATION

1. Noor Hisham Jalani, Jamaludin Jalani and Jiwa Abdullah (2008). Position

Control for Linear Servo System via Nominal Characteristic Trajectory

Controller (NCTF). Accepted for 3rd International Conference on

Mechatronics 2008 (ICOM'08), Kuala Lumpur, Malaysia.

vi

2. Jamaludin Jalani, Noor Hisham Jalani and Jiwa Abdullah (2008). Position

Control for Linear Servo System via Nominal Characteristic Trajectory

Controller (NCTF). Bronze Medal, Applied Research Category, Research and

Innovation Festival 2008, Universiti Tun Hussein Onn Malaysia, 14-16

vii

ABSTRACT

Motion control system is a challenging problem in the area of control

systems. It is very useful to demonstrate concepts in linear control such as the

stabilization of unstable systems. Motion control system plays important roles in

industrial equipment such as machine tools, semiconductor manufacturing systems

and robot systems. One type of motion control systems is point-to-point (PTP)

positioning system, which is used to move an object from one point to another point.

Linear motion servo system is a machine that move cart from one point to another

point. This system consists of a cart driven by a DC motor, via a rack and pinion

mechanism to ensure consistent and continuous traction.

Up to now many types of controllers have been proposed and evaluated for

positioning systems. Two type of controller that discussed in this thesis are

Proportional-Velocity (PV) and Nominal Characteristic Trajectory Following

(NCTF). The experimental results showed that the PV was successfully implemented

which controlled the settling time, rise time and steady-state error of the desired

position. However, the overshoot performances show its disadvantages.

Additionally, the PV controller design is time consuming process, since model and

parameters of the linear motion servo system are needed. Therefore, the needs for

higher performance controller become important for the simplicity of the controller

design. Hence, the investigation proceed with the non-model based NCTF controller

was to control the cart position of the linear motion servo system. The NCTF

controller consists of a Nominal Characteristic Trajectory (NCT) and PI

compensator. The NCTF controller was designed based on a simple open-loop

experiment of the object. The experimental results showed that the NCTF controller

is more effective for controlling position oflinear motion servo system than the PV

V111

ABSTRAK

Isu utama di dalam sistem kawalan ialah bagaimana untuk mengawal

pergerakan supaya kedudukan yang dikehendaki dapat dicapai. Ianya menjadi sangat

penting terutama sekali di dalam industri peralatan seperti pemesinan, sistem

pembuatan semikonduktor dan sistem robotik. Salah satu contoh sistem kawalan

pergerakan ialah pergerakan satu titik ke satu titik lain, seperti pergerakan objek dari

satu temp at ke satu tempat yang lain. Untuk mengkaji isu ini, ujikaji telah dijalankan

ke atas sistem servo pergerakan linear, yang menggerakkan kart dari satu titik ke satu

titik lain. Sistem ini mengandungi kart yang dipacu oleh motor AT, melalui landasan

dan mekanisme pinan untuk memastikan pergerakan yang konsisten dan berterusan.

Sehingga kini, banyakjenis pengawal yang dibangunkan untuk tujuan

mengawal ketepatan kedudukan. Di dalam tesis ini, dua jenis pengawal yang

dibincangkan ialah Proportional-Velocity CPV) dan Nominal Characteristic

Trajectol)' Following (NCTF). Keputusan ujikaji menunjukkan bahawa pengawal PV berjaya mengawal masa pengenapan, masa naik dan ralat keadaan mantap untuk

kedudukan yang dikehendaki. Bagaimanapun, prestasi untuk lajak adalah kurang

memuaskan. Tambahan pula, rekabentuk pengawal PV mengambil masa yang lebih

disebabkan model dan parameter sistem yang perlu diketahui dahulu. Oleh itu,

keperluan untuk pengawal yang berprestasi tinggi menjadi penting. Maka,

penyelidikan terhadap pengawal NCTF dicadangkan untuk sistem ini. Pengawal

NCTF mengandungi NCT dan pemampas PI. Ianya direkabentuk berasaskan ujkaji

sistem gelung buka terhadap objek. Keputusan ujikaji menunjukkan pengawal NCTF

lebih berkesan mengawal kedudukan sistem servo pergerakan linear berbanding

IX

CONTENTS

CHAPTER ITEM PAGE

TITLE PAGE

DECLARATION ii

DEDICATION iv

ACKNOWLEDGEMENT v

PUBLICATION vi

ABSTRACT vii

ABSTRAK viii

CONTENTS ix

LIST OF TABLES xii

LIST OF FIGURES xiii

LIST OF SYMBOLS xv

LIST OF ABBREVIATIONS xvii

I INTRODUCTION

1.1 Background

1.2 Problem Statement 2

1.3 Objectives of Project 2

1.4 Scopes of Project 2

x

II LITERATURE REVIEW

2.1 Introduction 5

2.2 Control Theory 5

2.2.1 Classical Control Theory 7

2.2.2 Closed-Loop Transfer Function 8

2.2.3 PID Controller 9

2.2.4 Modem Control Theory 10

2.3 Main Control Strategies 10

2.3.1 Adaptive Control 11

2.3.2 Hierarchical Control 11

2.3.3 Intelligent Control 11

2.3.4 Optimal Control 12

2.3.5 Robust Control 12

2.3.6 Stochastic Control 13

2.4 Related Work 13

III METHODOLOGY

3.1 Introduction 16

3.2 Methodology 16

3.3 Linear Motion Servo System 18

3.4 Experimental Configuration 19

3.5 Installation of Control Software 20

3.5.Mode 23

3.5.2 MathWorks 21

3.5.3 Ardence 21

3.6 Controller 22

IV MODELING AND PARAMETERS IDENTIFICATION

4.1 Introduction 23

4.2 Model Parameters 23

4.3 Modeling of Cart System 24

Xl

V DESIGN AND IMPLEMENT A TION OF PV CONTROLLER

5.1 Introduction 29

5.2 Standard Closed-Loop System 29

5.3 Proportional-plus-Derivative (PD) Control Scheme 31

5.4 Proportional-V e10city (PV) Control Scheme 31

5.5 PV ControIIer Design 32

5.6 Experimental Setup 36

5.7 Results 37

5.S Conclusion 41

VI DESIGN AND IMPLEMENTATION OF NCTF CONTROLLER

6.1. Introduction

6.2 NCTF ControIIer Structure

6.3 Basic Concept ofNCTF ControIIer

6.3 ControIIer Design

6.3.1 NCT Determination

6.3.2 Design of Compensator

6.4 Results

6.5 Conclusion

VII CONCLUSIONS

7.1 Conclusion

7.2 Future Studies

Xli

LIST OF TABLES

TABLES TITLE PAGE

4.1

Parameter of the cart system

24

5.1

Positioning performance for PV controller

38

6.1

PI compensator parameters design

50

6.2

Comparison ofthe performances for different compensator

to the step input

53

6.3

Simulated positioning performance for the controllers when

step input references were used

55

6.4

Experimental positioning perfonnance for the controllers when

step input references were used

55

6.5

Simulated positioning performance for the controllers when

square input references were used

56

6.6

Experimental positioning performance for the controllers when

X111

LIST OF FIGURES

FIGURES TITLE PAGE

1.1 Position control based machine

2.1

The concept ofthe feedback loop

6

2.2

Block diagram offeedback loop

8

3.1

Quanser control platform

17

3.2

Equipment of experiment setup

18

3.3

Linear motion servo system

19

3.4

Integration of overall systems

19

3.5

Real time control software

20

3.6

Flowchart of real-time control with Win Con

21

4.1

The cart system

25

4.2

DC motor electric circuit

26

5.1

Standard closed-loop position control system

30

5.2

Schematic diagram of linear servo system using PV controller

32

5.3

Serial connection between host and target computer to

the linear motion servo system

37

5.4

Results for position control when system is applied step input

39

5.5

Results for position control when system is applied square input

40

6.1

Schematic diagram of using NCTF controller

43

6.2

NCT and object motion

44

6.3

NCT determination

45

6.4

Simple open-loop response of the linear motion system for

NCT determination

48

6.5

Construction ofNCT oflinear motion system

49

6.7

6.8

6.9

Responses at different positions

The results for position responses to a step input

The results for position responses to a square input

XIV

52

57

LIST OF SYl\lBOLS

A Curve area

Beq Equivalent viscous damping coefficient at the motor pinion

Bp Viscous damping coefficient at the pendulum pivot

e Error

Fai Armature rotational inertial force, acting on the cart

Fe Cart driving force produced by motor

h Maximum error rate

Ip Pendulum moment of inertia

1m Motor armature current

1m Rotor moment inertia

Kg Planetary gearbox gear ratio

Ki Motor torque constant

Km EMF constant

Kp Proportional gain

Ki Integral gain

K\' Velocity gain

Ip Pendulum length frompivot to center of gravity

Lm Motor annature inductance

m Inclination of the NCT near origin

Mp Pendulum mass

PO Percent overshoot

rmp Motor pinion radius

rpp Position pinion radius

Rm Motor armature resistance

s Laplace operator

X \"I

tp Peak time

Tm Motor torque

up Difference actual error rate and NCT

Ur Rated input to the actuator

Vm Motor nominal input voltage

x Cart linear position

a

Simplified object parameter

77 g Planetary gearbox efficiency

77", Motor efficiency

OJm Motor shaft angular velocity

OJ" Undamped natural frequency

DAQ

PID

PD

PV

NCTF

LIST OF ABBREVIATIONS

Data Acquisition Card

Proportional Integral Derivative

Proportional Derivative

Proportional Velocity

Nominal Characteristic Trajectory Following

CHAPTER I

INTRODUCTION

1.1

Background

Motion control system is a challenging

problem in the

area of control

systems.

It

is very

useful to demonstrate

concepts

in linear

control such as

the

stabilization of

unstable

ystems. Motion control system

plays important roles in

industrial equipment

s

uch

as

machine tools

,

semiconductor

manufacturing

systems

and robot systems.

One type

of motion control systems is

point-to-point

(PTP)

positioning

system

,

which

is used

to

move

an object from one

point to another point.

2

1.2 Problem Statement

Up to now many types of controllers have been proposed and evaluated for

positioning systems. These controllers will give good positioning performance ifthe

controller was designed by an expert on motion control system whereby they use

exact model and real value for all parameters. Advanced controllers tend to be

complicated and requires in depth knowledge on theory and design. However, in

practicality, engineers are often asked to design this controller. Exact modeling and

parameter identifications are generally troublesome and time consuming tasks.

1.3 Objectives of Project

The objective of this study is to investigate the appropriate control method for

linear motion control system. The appropriate controller is expected to have simple

structure and easy to design, which does not require an exact model and its

parameters. The design of the proposed controller is based solely on the information

from a simple open-loop experiment.

1.4 Scopes of Project

The focus of this thesis is to investigate a proposed linear motion controller

based on Nominal Characteristic Trajectory Following (NCTF). The proposed

controller will be used to control the position of a cart horizontally. The design of

Module. Some hardware limitations would be imposed in the cart system. The

Digital-to-Analog voltage for data acquisition board is limited between -1 OV and

lOY. The safety watchdog is turned on where the allowable cart displacement is

O.35m from the centre of the track.

1.5 Thesis Layout

The thesis is organized as follows:

Chapter I: In this chapter will explain an introduction to the linear motion

servo system. The introduction consists of background, problem statement, and

objective, scope of project and research methodology.

3

Chapter 2: This chapter consists ofthe previous study and the information of

the linear motion servo system. Its will cover the literature research based on

positioning control oflinear motion system.

Chapter 3: In order to achieve the objectives of this study, this chapter will

explain the methodology of the project.

Chapter 4: This chapter will explain how the linear motion servo system is

modelled mathematically. The mathematical modeling which consists of the model

derivation and parameter identification is explained.

Chapter 5: The performance ofPV controller as a benchmark controller is

discussed in this chapter. The design and implementation ofPV controller for linear

J

Chapter 6: Since the

rv

controller shows that thc p()or rc~ultlll1 (1\·cr,hnnl. ;\ new controller which is called NCTF is proposed and discusscd in thi~ chaptcr. The NCTF controller was designed based on a simple opcn-Ioop cxpcrimcnt (1C the nhjl'CI. The basic concept, design and implementation of the ;\CTF contrnllcr arc cxplained. The perfonnance of the NCTF controller was analyscd and concludcd.

CHAPTER II

LITERATURE REVIEW

2.1 Introduction

Literature survey has been carried out in order to gain enough knowledge

regarding the project. The comparison and selection of the best designing technique

will then be done accordingly. The objective of this chapter is to critically review the

existing controller methodology, characteristics and features. Particular emphasise

will be given to PV and NCTF controller design. Recently published papers will be

considered.

2.2 Control Theory

Control theory is an interdisciplinary branch of engineering and mathematics,

that deals with the behavior of dynamical systems. The desired output of a system is

called the referellce. When one or more output variables of a system need to follow a

certain reference over time, a controller manipulates the inputs to a system to obtain