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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.
Tesis dimaksudkan sebagai tesis bagi Ijazah Doktor Falsafah dan Sarjana secara penyelidikan, at au disertai bagi pengajian secara kerja lmrsus dan penyelidikan, atau Laporan Projek Sarjana Muda (PSM).
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
NOVEMBER 2008
"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
.... \}.~~ .. ~ ............... .
11
"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 ~ .................................................
111
\.
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
anything positive in me.
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
October 2008.
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
controller.
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
pengawal PV.
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
1.5 Thesis Layout 3
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
4.4 Conclusion 28
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
REFERENCES
APPENDIXES
42
42
43
47
47
49
54
59
60
61
62
64
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
square input references were used 56
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
6.6 Responses on phase plane 51
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
58
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
Continuous time
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
,; Damping ratio
DAQ
PID
PD
PV
NCTF
LIST OF ABBREVIATIONS
Data Acquisition Card
Proportional Integral Derivative
Proportional Derivative
Proportional Velocity
Nominal Characteristic Trajectory Following
XVll
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 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.
Figure! .l : Position control based machine
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
proposed controller will be implemented on Quanser IP02 Liner Motion Servo
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
motion servo system is also described in this chapter.
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 7: This chapter summarizes all the results obtaincd in thc pre\'illllS
chapter. The recommendation for future study is suggested.
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
the desired effect on the output ofthe system (wikipedia.org/wiki/control, 2008).