UNIVERSITI PUTRA MALAYSIA

MOHAMMADREZA ABDOLLAHI

FK 2011 73

DESIGN AND EVALUATION ON ADAPTIVE FUZZY SPEED CONTROL OF MOBILE ROBOT

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DESIGN AND EVALUATION ON ADAPTIVE FUZZY SPEED CONTROL

OF MOBILE ROBOT

By

MOHAMMADREZA ABDOLLAHI

Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia,

in Fulfillment of the Requirements for the Degree of Master of Science

April 2011

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Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfilment

of the requirement for the degree of Master of Science

DESIGN AND EVALUATION ON ADAPTIVE FUZZY SPEED CONTROL

OF MOBILE ROBOT

By

MOHAMMADREZA ABDOLLAHI

April 2011

Chairman : Associate Professor Mohammad Hamiruce bin Marhaban, PhD

Faculty : Engineering

Wheeled mobile robots are widely used in various fields such as agriculture,

industry, land mining, military, space explorations, and other applications in which

the environment is inaccessible or hazardous to human, such as in nuclear plants.

This thesis mainly focuses on investigation of fuzzy logic approach capability in

order to control the speed of a four-wheel mobile robot in an indoor environment.

This research deals with adaptive fuzzy speed control of mobile robot in an indoor

environment with variable slope. Two different method are used for tuning

mechanism consist of on-line tuning of output gain and output membership

functions. Given a reference trajectory, the performances of these methods are

compared with fuzzy PI controller (FPIC), through experimental evaluations. The

first method is self-tuning fuzzy logic controller by means of updating output scaling

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factor. Depending on the process trend, the output scaling factor (SF) of the

controller is modified by an updating factor (α), in an online fashion. The value of α

is determined through a rule-based adaptive mechanism defined over error and the

pitch angle of the robot. In the second adaptive method, membership functions

tuning, a direct adaptive fuzzy controller is used to modify the locations of the output

membership functions, adaptively. The controller has a fuzzy rule base that can adopt

different output membership functions for each fuzzy rule to improve the

performance of the fuzzy controller, in spite of changes in the plant. The

effectiveness of the control system is verified through real time experiments in an

indoor environment with different slope. Both data acquisition and control algorithm

are developed by using LabVIEW. A four-wheel mobile robot, PUTRABOT2, is

used to conduct the experiments. Performance comparison between the fuzzy PI

controller and adaptive fuzzy controllers are made in terms of several performance

criteria including rise time, settling time, peak time, peak overshoot, integral absolute

error (IAE) and integral time weighted absolute error (ITAE). Comparative results

for various processes in term of different angle of ramp (15, 20 and 25 degree) show

that the adaptive fuzzy controllers outperform the fuzzy PI controller to minimize the

rise time, settling time IAE and ITAE, except peak overshoot. This research paves

the way towards the adaptive control of mobile robots in the face of plants

uncertainty and would be appreciated by urban and industrial applications.

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Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai

memenuhi keperluan untuk ijazah Master Sains

REKA BENTUK DAN PENILAIAN ATAS KAWALAN HALAJU SAMAR

MUDAH SUAI UNTUK ROBOT BERGERAK

Oleh

MOHAMMADREZA ABDOLLAHI

April 2011

Pengerusi : Profesor Madya Mohammad Hamiruce bin Marhaban, PhD

Fakulti : Kejuruteraan

Robot bergerak beroda digunakan secara meluas di dalam pelbagai bidang seperti

pertanian, perlombongan, ketenteraan, penjelajahan angkasa dan lain-lain aplikasi di

mana persekitarannya tidak dapat didatangi atau berbahaya kepada manusia, seperti

loji nuklear. Tesis ini memberi fokus utama kepada penyelidikan tentang kebolehan

pendekatan logik samar di dalam mengawal halaju untuk pengemudi gelincir robot

bergerak empat-roda di dalam persekitaran bilik dengan cerunan berbeza. Dua

kaedah berbeza digunakan untuk mekanisma penalaan yang mengandungi penalaan

perolehan output dalam talian dan fungsi keahlian. Berdasarkan isyarat rujukan,

prestasi kaedah ini dibandingkan dengan alat kawalan samar PI melalui ujikaji

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penilaian. Kaedah pertama ialah penalaan sendiri kawalan logik samar menggunakan

faktor skalar output. Berdasarkan aliran proses, faktor skalar output atau output

scaling factor (SF) bagi alat kawalan diubah menggunakan faktor pengemaskinian

atau updating factor (α) gaya dalam talian. Nilai α diperolehi melalui mekanisme

dasar-peraturanmudahsuai yang didefinasi melalui ralat dan sudut pic robot. Di

dalam kaedah mudah suai kedua, mekanisme fungsi keahlian, kawalan mudah suai

terus digunakan untuk merubah lokasi fungsi keahlian output, secara mudah suai.

Alat kawalan mempunyai peraturan asas samar yang boleh menerima pelbagai fungsi

keahlian output untuk setiap peraturan samar bagi memperbaiki prestasi alat kawalan

samar, walaupun terdapat perubahan persekitaran loji. Keberkesanan sistem kawalan

ini dipastikan melalui ujikaji di dalam persekitaran bilik dengan cerunan berbeza.

Kedua-dua pemerolehan data dan algoritm kawalan dibina menggunakan perisian

computer LabVIEW. Pengemudi gelincir robot bergerak empat roda, PUTRABOT2

digunakan di dalam ujikaji. Perbandingan prestasi di antara alat kawalan logik samar

konvensional dan kawalan logic samar mudah suai dibuat dari segi beberapa criteria

prestasi termasuk masa bangkit, masa enapan, masa puncak, puncak melampau, ralat

mutlak keseluruhan dan ralat mutlak berpemberat masa keseluruhan. Keputusan

perbandingan untuk pelbagai proses dari segi sudut tanjakan berbeza (15, 20 dan 25

darjah) menunjukkan kawalan logik samar mudah suai mengatasi prestasi kawalan

logik samar PI bagi meminimumkan masa bangkit, masa enapan, ralat mutlak

keseluruhan dan ralat mutlak berpemberat kecuali puncak melampau. Penyelidikan

ini membuka jalan menuju kawalan mudah suai robot bergerak di dalam persekitaran

loji yang tidak pasti, dan lebih dihargai oleh applikasi bandar dan industri.

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ACKNOWLEDGEMENT

In the name of Allah, the Most Gracious, the Most Merciful.

First and foremost, I would like to express my gratitude to Allah, for giving guidance

and ability to complete my thesis.

I would like to give respectfully all my sincere thanks to my supervisor Dr.

Mohammad Hamiruce Marhaban, for his support, concerns, times and sincerity that I

received during my study. The thesis is indebted his support, encouragement and

useful comments. Thanks and appreciation is extended to the member of the

supervisory committee Dr. Samsul Bahari Mohd Noor, for his advices and insightful

comments, which guide me through the proper direction.

My greatest thanks go to my parents, who always have encouraged and supported me

in each state of my life, also thank to my good brothers and sisters. I would like to

express my deepest gratitude to my mother in law and brothers in law, Mohammad

and Ali Karimadini, who are always around for me. This thesis would not have been

possible without their support, love and understandings. I also would like to thank

my dear friends, Ehsan Keramati, Omar F. Lutfi, Hazem I. Ali and all students in

robotic research laboratory for help and the assistance they gave me in many ways.

My final thanks are for my wife, Fatemeh, who is unique and the thesis could not

been done without her attention and best helps and my son, the dearest persons in my

life.

Peace and blessing upon Prophet Mohammad (S.A.W).

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I certify that a Thesis Examination Committee has met on 29 April 2011 to conduct the final examination of Mohammadreza Abdollahi on his thesis entitled "DESIGN AND EVALUATION ON ADAPTIVE FUZZY SPEED

CONTROL OF MOBILE ROBOT" in accordance with the Universities and University Colleges Act 1971 and the Constitution of the Universiti Putra Malaysia [P.U.(A) 106] 15 March 1998. The Committee recommends that the student be awarded the Master of Science degree.

Members of the Thesis Examination Committee were as follows:

Maryam Mohd Isa, PhD

Faculty of Engineering Universiti Putra Malaysia (UPM) (Chairman)

Raja Mohd Kamil Raja Ahmad, PhD

Faculty of Engineering Universiti Putra Malaysia (UPM) (Internal Examiner) Tang Sai Hong, PhD

Associate Professor Faculty of Engineering Universiti Putra Malaysia (UPM) (Internal Examiner) Mohd Rizal Arshad, PhD

Associate Professor Engineering Campus Universiti Sains Malaysia (USM) (External Examiner)

SHAMSUDDIN SULAIMAN, PhD

Professor and Deputy Dean School of Graduate Studies Universiti Putra Malaysia Date:

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This thesis was submitted to the Senate of Universiti Putra Malaysia and has been

accepted as fulfillment of the requirement for the degree of Master of Science. The

members of the Supervisory Committee were as follows:

Mohammad Hamiruce bin Marhaban, PhD

Associate Professor

Faculty of Engineering

Universiti Putra Malaysia

(Chairman)

Samsul Bahari Mohd Noor, PhD

Associate Professor

Faculty of Engineering

Universiti Putra Malaysia

(Member)

HASANAH MOHD. GHAZALI, PhD Professor and Dean

School of Graduate Studies

Universiti Putra Malaysia

Date :

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DECLARATION

I declare that the thesis is my original work except for quotations and citations which

have been duly acknowledged. I also declare that it has not been previously, and is

not concurrently, submitted for other degree at University Putra Malaysia or at any

other institution.

________________________________

MOHAMMADREZA ABDOLLAHI

Date: 29 April 2011

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TABLE OF CONTENTS

Page

ABSTRACT ii

ABSTRAK iv

ACKNOWLEDGEMENT vi

APPROVAL vii

DECLARATION ix

LIST OF TABLES xiii

LIST OF FIGURES xiv

LIST OF ABBREVIATIONS xvii

CHAPTER

1 INTRODUCTION ........................................................................................... 1

1.1 Background 1

1.2 Problem Statement 2

1.3 Research Objectives 3

1.4 Scope of Work 4

1.5 Research Contributions 4

1.6 Layout of the Thesis 5

2 LITERATURE REVIEW ................................................................................ 7

2.1 Mobile Robot 7

2.2 Mobile Robot Positioning 8

2.2.1 Absolute Positioning 8

2.2.2 Relative Positioning 9

2.3 Dead Reckoning 10

2.3.1 Sensors for Odometry 13

2.3.2 Optical Encoders 14

2.3.3 Incremental Optical Encoder 14

2.4 MEMS Accelerometers 16

2.4.1 MEMS Structure and Technology 17

2.4.2 Sensing Tilt with MEMS Accelerometers 18

2.5 Fuzzy Systems and Fuzzy Logic 20

2.5.1 Limitation of Conventional Control 21

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2.5.2 Advantages and Disadvantages of Fuzzy Control 22

2.6 Fuzzy Logic Controller 23

2.6.1 Fuzzy PD-Like Controller 24

2.6.2 Fuzzy PI-Like Controller 25

2.7 Adaptive Fuzzy Logic Controller 27

2.8 Speed Control of Mobile Robot 43

2.9 Summary 48

3 METHODOLOGY ........................................................................................ 49

3.1 Introduction 49

3.2 Mobile Robot 50

3.2.1 Hardware and Platform 50

3.2.2 Software 55

3.2.3 Interface 56

3.3 Experimental setup 59

3.4 Control System 62

3.4.1 Fuzzy Logic Controller 62

3.4.2 Adaptive Fuzzy Logic Controller 70

3.4.3 Adaptive Fuzzy Logic Controller Using On-line Tuning of Output.

. Scaling Factor 72

3.4.4 Adaptive Fuzzy Controller by Updating the Locations of

. Membership Functions (AFLC-MF) 78

3.5 Summary 83

4 EXPERIMENTAL RESULTS AND DISCUSSION .................................... 84

4.1 Introduction 84

4.2 Conventional Fuzzy Controller 86

4.2.1 Reference Tracking 90

4.2.2 Robot with Fuzzy PI Controller on the Ramp 93

4.3 Adaptive Fuzzy Logic Controller by Updating Output Scaling Factor 99

4.4 Adaptive Fuzzy Logic Controller by Updating the Location of

. Membership Functions 104

4.5 Performance Analysis 109

4.6 Summary 113

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5 CONCLUSIONS AND RECOMMENDATIONS ...................................... 114

5.1 Conclusions 114

5.2 Recommendations and Future Work 116

REFERENCES 118

APPENDIX A 125

APPENDIX B 127

APPENDIX C 129

BIODATA OF STUDENT 131