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Faculty of Electrical Engineering
SCALING OF MDOF MICRO-MACRO BILATERAL CONTROL TELEOPERATION SYSTEM USING STANDARDIZED MODAL
SPACE
Lee Jun Wei
Master of Science in Mechatronic Engineering
2016
SCALING OF MDOF MICRO-MACRO BILATERAL CONTROL TELEOPERATION SYSTEM USING STANDARDIZED MODAL SPACE
LEE JUN WEI
A thesis submitted in fulfilment of the requirements for the degree of Master of Science in Mechatronic Engineering
Faculty of Electrical Engineering
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
2016
DECLARATION
I declare that this thesis entitled “Scaling of MDOF Micro-Macro Bilateral Control
Teleoperation System Using Standardized Modal Space” is the result of my own research
except as cited in the references. The thesis has not been accepted for any degree and is not
concurrently submitted in candidature of any other degree.
Signature : ……………………………..
Name : ….... LEE JUN WEI ………
Date : …..……30/8/2016……..…..
APPROVAL
I hereby declare that I have read this thesis and in my opinion this thesis is sufficient in terms
of scope and quality for the award of Master of Science in Mechatronic Engineering.
Signature : …………………………………………………..
Supervisor Name : ……DR. AHMAD ZAKI BIN HJ SHUKOR…..
Date : ……………...……30/8/2016……………….…..
DEDICATION
To my beloved Mother and in my loving memory of Father
Thank you for your incessant support and encouragement. Your sacrifices and loves have
helped me to achieve this accomplishment.
Dear Supervisor, co-Supervisor and Lecturers
Thank you for your continuous support, knowledge and guidance.
Dear Friends
Thank you for all the information, guidance, support and encouragement.
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ABSTRACT
In future, robots and mechatronic system are required to support human, they should have a lot of abilities such as recognition of the real world based on the complicated human action to environment based on human sensation and so on. The word “Haptic” means sense of touch and haptic information is studied as the third type of multimedia information. Unlike audio and visual information which is transmitted to one direction (unilateral), haptic information is bidirectional information (bilateral), which applied “law of action and reaction” a tactile information in bilateral information. Thus, a bilateral control system with master and slave manipulator to transmit the information bilaterally has been researched. In this thesis, bilateral teleoperation control system is implemented in single link planar and two link planar manipulator which consisted of master and slave system. The modelling of bilateral teleoperation control system is designed with the integration of Disturbance Observer (DOB), Reaction Force/Torque Observer (RFOB)/(RTOB), position controller and force controller. Then further research on micro-macro bilateral teleoperation control system is done on multi degree-of-freedoms (MDOF) which is two link planar manipulator. The micro-macro bilateral control teleoperation system provides the human operator with a sense of feel to a micro or macro environment as if it is in the same scale environment. However, the micro-macro bilateral control system of this thesis consists of same size structure between master and slave manipulator. Thus a standardized modal space method is proposed to achieve for MDOF micro-macro bilateral control teleoperation system. This method able to scale the force and position information between master slave system. It is a novel method for transmission of force and motion in macro environment in order to realize the physical support for the macro activities. Nevertheless, this proposed method able to scale the haptic information between the master and slave system accordingly. To validate the performance of common mode and differential mode of the proposed method, 4 cases of free and contact motion experiments with different nominal mass ratio between master and slave system are conducted. Then the root-mean-square deviation of the nominal mass ratio and scaling α gain from 4 different cases is 1.12 × 10−5 and 2.55 × 10−5 for 𝑥 -axis and 𝑦 -axis, respectively. As conclusion, this proved that the standardized modal space method is able to scale different force information of MDOF micro-macro bilateral control teleoperation system.
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ABSTRAK
Pada masa akan datang, robot dan sistem mekatronik diperlukan untuk menyokong manusia, mereka harus mempunyai banyak kebolehan seperti pengiktirafan dunia sebenar berdasarkan tindakan manusia yang rumit kepada alam sekitar berdasarkan sensasi manusia dan sebagainya. Perkataan "Haptic" ertinya rasa sentuhan dan maklumat haptic dikaji sebagai jenis ketiga maklumat multimedia. Tidak seperti maklumat audio dan visual yang dihantar ke satu arah (unilateral), maklumat haptic adalah maklumat dwiarah (dua hala), yang menggunakan "undang-undang tindakan dan reaksi" maklumat sentuhan di dalam maklumat dua hala. Oleh itu, satu sistem kawalan dua hala dengan induk dan hamba pengolah untuk menghantar maklumat secara dua hala telah dikaji. Dalam tesis ini, sistem kawalan teleoperasi dua hala dilaksanakan dalam satu satah penghubung dan dua satah penghubung pengolah yang terdiri daripada sistem induk dan hamba. Pemodelan sistem kawalan teleoperasi dua hala direka dengan integrasi Pemerhati Gangguan (DOB), Permerhati Reaksi Daya / Permerhati Reaksi Kilas (RFOB) / (RTOB), pengawal posisi dan pengawal daya. Kemudian penyelidikan lanjut mengenai kawalan sistem teleoperasi dua hala mikro-makro dilakukan pada pelbagai darjah kebebasan (MDOF) yang merupakan dua satah penghubung pengolah. Sistem kawalan teleoperasi dua hala mikro-makro memberi pengendali manusia untuk merasa persekitaran mikro atau makro seolah-olah ia adalah dalam persekitaran yang sama saiz. Walaubagaimanapun, sistem kawalan dua hala mikro-makro tesis ini terdiri daripada struktur saiz sama antara induk dan hamba pengolah. Oleh itu kaedah ruang model yang seragam adalah dicadangkan untuk mencapai sistem teleoperasi kawalan dua hala mikro-makro MDOF. Kaedah ini dapat mengubah skala maklumat daya dan maklumat posisi antara sistem induk hamba. Ia adalah satu kaedah baru untuk penghantaran daya dan gerakan dalam persekitaran makro bagi merealisasikan sokongan fizikal untuk aktiviti-aktiviti makro. Bagaimanapun, kaedah yang dicadangkan ini mampu mempertingkatkan maklumat haptik antara sistem induk dan hamba sewajarnya. Untuk mengesahkan prestasi mod lazim dan mod berbeza daripada kaedah yang dicadangkan, 4 kes eksperimen gerakan bebas dan sentuhan dengan nisbah jisim nominal yang berbeza di antara sistem induk dan hamba dijalankan. Kemudian punca purata kuasa dua sisihan bagi nisbah jisim nominal dan berskala α dari 4 kes yang berbeza adalah 1.12 ×10−5 and 2.55 × 10−5 bagi paksi-x dan paksi-y. Sebagai kesimpulan, ini membuktikan bahawa kaedah ruang model yang seragam mampu untuk mengubah skala maklumat daya yang berbeza bagi sistem teleoperasi kawalan dua hala mikro-makro MDOF.
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ACKNOWLEDGEMENTS
First and foremost, I would like to take this opportunity to thank my beloved and respected
supervisor Dr. Ahmad Zaki bin Hj Shukor from Faculty of Electrical Engineering Universiti
Teknikal Malaysia Melaka (UTeM) for giving the support mentally and physically, by
sharing his expertise, knowledge and experience with me.
I would also like to express my greatest gratitude to Dr. Muhammad Herman bin Jamaluddin
from Faculty of Electrical Engineering Universiti Teknikal Malaysia Melaka (UTeM), co-
supervisor of this research for his advice and suggestions in haptic system. Special thanks to
UTeM short term grant funding for the research material support. Nevertheless, special
thanks also to SKIM ZAMALAH scholarship for the financial support throughout this
research period.
Special thanks to Prof. Madya Dr. Fahmi bin Miskon, Dr. Fariz bin Ali @ Ibrahim and Mohd
Bazli bin Bahar for their support when having shortage in funding for the research material.
I am highly indebted to pioneer, Prof. Yasutaka Fujimoto who have provided me with the
valuable guidance and advise which motivated me, and I appreciated it with all of my heart.
Special thanks to all my beloved mother, my late father and siblings for their moral support
in completing this master. Last but not least, a million thanks to all those time, concern and
efforts that were given to me during the whole process of completing this research and thesis.
I am thankful to everyone who always inspires me directly and indirectly during master
program.
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TABLE OF CONTENTS
PAGE DECLARATION APPROVAL DEDICATION ABSTRACT i ABSTRAK ii ACKNOWLEDGEMENTS iii TABLE OF CONTENTS iv LIST OF TABLES vii LIST OF FIGURES ix LIST OF APPENDICES xii LIST OF ABBREVIATIONS xiii LIST OF PUBLICATIONS xv CHAPTER 1. INTRODUCTION 1
1.0 Background/Motivation 1
1.1 Problem Statement 3
1.2 Objective 5
1.3 Scope 5
1.4 Contribution of the Thesis 6
2. LITERTURE REVIEW 7
2.0 Introduction 7
2.1 Background on Workspace Control 8
2.2 Introduction to Haptic System 9
2.3 Bilateral Control System 12
2.4 Disturbance Observer (DOB) and Reaction Force/Torque Observer (RFOB)/(RTOB) 15
2.5 Various Implementation on Bilateral Control System 18
2.6 Background on Micro-Macro Bilateral Control System 21
2.7 Summary 24
3. METHODOLOGY 28
3.0 Introduction 28
3.1 Experimental Setups 30
3.1.1 Implementation of Force Gauge 38
3.2 Part I: Workspace Control of Two-Link Planar Manipulator 40
3.2.1 Comparison of Control Methods 41
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3.2.2 Single Link Manipulator Close Loop Control System 42
3.2.3 Two Link Manipulator Close Loop Control System 44
3.2.4 Workspace Control Method 1 47
3.2.5 Workspace Control Method 2 48
3.2.6 Workspace Control Method 3 52
3.2.7 Experiment Procedure for Part I 55
3.3 Part II: Single Link Planar Manipulator Bilateral Control System 56
3.3.1 Disturbance Observer (DOB) and Reaction Torque Observer (RTOB) 60
3.3.2 Experiment Procedure for Part II 64
3.4 Part III: Two-Link Planar Manipulator Bilateral Control System 65
3.4.1 Workspace Observer (WOB) and Reaction Force Observer (RFOB) 70
3.4.2 Experiment Procedure for Part III 73
3.5 Part IV: Single Link Planar Manipulator Micro-Macro Bilateral Control System 75
3.5.1 Experiment Procedure for Part IV 78
3.6 Part V: Two-Link Planar Manipulator Micro-Macro Bilateral Control System 79
3.6.1 Experiment Procedure for Part V 81
3.7 Stochastic Tuning of Gains 83
3.8 Performance of Common Mode and Differential Mode 86
4. RESULT AND DISCUSSION 88
4.0 Introduction 88
4.1 Part I: Workspace Control of Two-Link Planar Manipulator 89
4.1.1 Observation and Findings 93
4.2 Part II: Single Link Planar Manipulator Bilateral Control System 94
4.2.1 Free and Contact Motion Experiment 98
4.3 Part III: Two-Link Planar Manipulator Bilateral Control System 100
4.3.1 Free and Contact Motion Experiment 101
4.4 Part IV: Single Link Planar Manipulator Micro-Macro Bilateral Control System 104
4.4.1 Free and Contact Motion Experiment 105
4.5 Part V: Two-Link Planar Manipulator Micro-Macro Bilateral Control System 108
4.5.1 Free and Contact Motion Experiment 110
4.5.1.1 Case 1 111
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4.5.1.2 Case 2 112
4.5.1.3 Case 3 114
4.5.1.4 Case 4 116
4.5.2 α𝑥 and α𝑦 Gains Experiment 118
4.5.2.1 Case 1 118
4.5.2.2 Case 2 119
4.5.2.3 Case 3 120
4.5.2.4 Case 4 121
4.5.3 Observations and Findings 122
4.6 Summary 123
5. CONCLUSION AND RECOMMENDATIONS FOR FUTURE RESEARCH 126
5.0 Conclusion 126
5.1 Future Work 127
REFERENCES 129
APPENDICES 141
vii
LIST OF TABLES
TABLE TITLE PAGE
2.1 Comparison of Scaling Methods 23
3.1 Control Methods 42
4.1 Parameters in Experiment in Part I 89
4.2 Parameters in Experiment in Part II 95
4.3 Performance Result (Part I) 100
4.4 Parameters in Experiment in Part III 101
4.5 Performance Result (Part II) 104
4.6 Parameters in Experiment in Part IV 105
4.7 Performance Result (Part III) 107
4.8 Parameters in Experiment in Part V 109
4.9 Ratio of Nominal Mass and Length of the Link Between
Master and Slave System 110
4.10 Performance result (Case 1) 112
4.11 Performance result (Case 2) 114
4.12 Performance result (Case 3) 116
4.13 Performance result (Case 4) 118
4.14 Average scaling ratio of α𝑥 and α𝑦 (Case 1) 119
viii
4.15 Average scaling ratio of α𝑥 and α𝑦 (Case 2) 120
4.16 Average scaling ratio of α𝑥 and α𝑦 (Case 3) 121
4.17 Average ratio of α𝑥 and α𝑦 (Case 4) 122
4.18 Error for Case 1 to Case 4 123
ix
LIST OF FIGURES
FIGURE TITLE PAGE
2.1 Directional property of human sensation 11
2.2 Sensory substitution by bilateral motion control 13
3.1 Flow chart 28
3.2 Experimental setup for Part I 30
3.3 Experimental setup for Part II 31
3.4 Experimental setup for Part IV 31
3.5 Parts from a single manipulator for Part II and Part IV 32
3.6 Overall diagram of the system for Part II and Part IV 32
3.7 Experimental setup Experimental setup for Part III 33
3.8 Experimental setup Experimental setup for Part V 33
3.9 Parts from a single manipulator for Part III and Part V 34
3.10 Overall diagram of the system for Part III and Part V 34
3.11 Two identical DC-motor with different gear ratio 35
3.12 Model of inertia and gear ratio 35
3.13 Micro-Box 2000 x86 Based Real-Time System 37
3.14 Micro-Box 2000 I/O pins 38
3.15 MARK-10 digital force gauge Series 3 39
3.16 Data acquisition software 39
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3.17 Features of the digital force gauge 40
3.18 Response of step input of angle 90˚ 44
3.19 Response of trajectory when target point is at (0.1, 0.2) 45
3.20 Response of trajectory when target point is at (-0.1, 0.2) 45
3.21 Response of trajectory when target point is at (-0.1, -0.2) 46
3.22 Response of trajectory when target point is at (0.1, -0.2) 46
3.23 Block Diagram of Method 1 47
3.24 Two link planar manipulator 48
3.25 Block Diagram Method 2 51
3.26 Block Diagram of Method 3 53
3.27 Block diagram of single link planar manipulator bilateral
control based on acceleration control 57
3.28 Four channel bilateral controller 59
3.29 Block diagram of joint space based DOB and RTOB 60
3.30 Part II free and contact motion experiment 64
3.31 Block diagram of two link planar manipulator bilateral control
based on acceleration control 66
3.32 Four channel bilateral controller 69
3.33 Block diagram of WOB and RFOB 70
3.34 Part III free and contact motion experiment 74
3.35 Direction of applied force at the end-effector of master manipulator
(top view) 74
3.36 Scaling method of single DOF micro-macro bilateral control system 78
3.37 Part IV free and contact motion experiment 79
3.38 Proposed method of MDOF micro-macro bilateral control system 81
xi
3.39 Part V free and contact motion experiment 82
4.1 (a) Oval and (b) straight line trajectory of Method 1
(Inverse Kinematics + PD) 90
4.2 (a) Oval and (b) straight line trajectory of Method 2
(Direct Cartesian + PD) 91
4.3 (a) Oval and (b) straight line trajectory of Method 3
(Direct Cartesian + PD + WOB) 92
4.4 Force gauge on master manipulator 96
4.5 Slave manipulator contact on static hard object 96
4.6 Force measurement for single link bilateral teleoperation control system 96
4.7 Force data from data acquisition software (in Newton) 97
4.8 Estimated reaction torque by RTOB at master and slave system 97
4.9 Torque and position response during free and contact motion 99
4.10 Force and position response during free and contact motion 102
4.11 XY trajectory response during free and contact motion 103
4.12 Torque and position response during free and contact motion 106
4.13 Force and position response during free and contact motion (Case 1) 111
4.14 Force and position response during free and contact motion (Case 2) 113
4.15 Force and position response during free and contact motion (Case 3) 115
4.16 Force and position response during free and contact motion (Case 4) 117
4.17 Scaling ratio of α𝑥 and α𝑦 (Case 1) 119
4.18 Scaling ratio of α𝑥 and α𝑦 (Case 2) 120
4.19 Scaling ratio of α𝑥 and α𝑦 (Case 3) 121
4.20 Scaling ratio of α𝑥 and α𝑦 (Case 4) 122
xii
LIST OF APPENDICES
APPENDIX TITLE PAGE A Motor Specification 141
B Gearhead Specification 143
C Encoder Specification 144
D Driver Specification 149
E Micro-Box Specification 150
F Force Gauge Specification 152
G Part I Method 1 154
H Part I Method 2 155
I Part I Method 3 157
J Part II Simulink Block Diagram 159
K Part III Simulink Block Diagram 160
L Part IV Simulink Block Diagram 163
M Part V Simulink Block Diagram 164
xiii
LIST OF ABBREVIATIONS
𝑙1 - Link 1
𝑙2 - Link 2
𝐽 - Real inertia
𝐽𝑛 - Nominal inertia
𝑀 - Real mass
𝑀𝑛 - Nominal mass
𝐽𝐿 - Load inertia
𝑁1: 𝑁2 - Gear ratio
𝐾𝑡𝑛 - Nominal torque constant
α - Arbitrary scaling factor of position
β - Arbitrary scaling factor of force
𝐾𝑝 - Position gain
𝐾𝑑 - Velocity gain
𝐾𝑎 Acceleration gain
𝐾𝑓 - Force gain
𝐶𝑝 - Position controller
𝐶𝑓 - Force controller
ꙍ𝑛 - Natural angular frequency
xiv
𝛿 - Damping coefficient
𝑔𝑑𝑜𝑏 - Cut-off frequency of disturbance observer
𝑔𝑟𝑡𝑜𝑏 - Cut-off frequency of reaction torque observer
𝐽𝑎𝑐𝑜 - Jacobian
𝐽𝑎𝑐𝑜𝑇 - Jacobian transpose
𝜏 - Torque
𝐹 - Force
𝜃 - Angle
�� - Angular velocity
�� - Angular acceleration
𝑥 - Displacement
�� - Velocity
�� - Acceleration
(𝑠𝑢𝑝𝑒𝑟𝑠𝑐𝑟𝑖𝑝𝑡)𝑟𝑒𝑓 - Reference value
(𝑠𝑢𝑝𝑒𝑟𝑠𝑐𝑟𝑖𝑝𝑡)𝑟𝑒𝑠 - Response value
(𝑠𝑢𝑝𝑒𝑟𝑠𝑐𝑟𝑖𝑝𝑡)𝑑𝑖𝑠 - d value
(𝑠𝑢𝑝𝑒𝑟𝑠𝑐𝑟𝑖𝑝𝑡)𝑒𝑥𝑡 - External value
(𝑠𝑢𝑏𝑠𝑐𝑟𝑖𝑝𝑡 )𝑀 - Master system
(𝑠𝑢𝑏𝑠𝑐𝑟𝑖𝑝𝑡 )𝑆 - Slave system
(𝑠𝑢𝑏𝑠𝑐𝑟𝑖𝑝𝑡 )𝐶 - Common mode
(𝑠𝑢𝑏𝑠𝑐𝑟𝑖𝑝𝑡 )𝐷 - Differential mode
(𝑠𝑢𝑏𝑠𝑐𝑟𝑖𝑝𝑡 )𝑥 - 𝑥-position
(𝑠𝑢𝑏𝑠𝑐𝑟𝑖𝑝𝑡 )𝑦 - 𝑦-position
- Estimated value
xv
LIST OF PUBLICATIONS
The following publication have been achieved by this research work.
Journals:
1) L. J. Wei, A. Z. H. Shukor, and M. H. Jamaluddin, “Workspace Control of Two Link
Planar Robot Using Micro-Box 2000,” J. Teknol., vol. 77, no. 20, pp. 9–18, 2015.
(SCOPUS)
2) L. J. Wei, A. Z. H. Shukor, and M. H. Jamaluddin, “Investigation on the Effects of Outer-
Loop Gains , Inner-Loop Gains and Variation of Parameters on Bilateral Teleoperation
Control System Using Geared DC-Motor,” Int. J. Mech. Mechatronics Eng. IJMME-
IJENS, vol. 16, no. 01, pp. 54–69, 2016. (SCOPUS)
3) L. J. Wei, A. Z. H. Shukor, and M. H. Jamaluddin, “Investigation on MDOF Bilateral
Teleoperation Control System Using Geared DC-Motor,” Modern Applied Science, vol.
10, no. 11, pp. 54–66, 2016. (SCOPUS)
4) L. J. Wei, A. Z. H. Shukor, and M. H. Jamaluddin, “Investigation on Standardization of
Modal Space by Ratio for MDOF Micro-Macro Bilateral Teleoperation Control System,”
Modern Applied Science, vol. 10, no. 11, pp. 98-109, 2016. (SCOPUS)
1
CHAPTER 1
INTRODUCTION
1.0 Background/Motivation
Imagine a world that human being is strong, able to be present in deep underwater,
or outer space to explorer and feel the environment which normal human being cannot exist
and able carry big and heavy objects. Unfortunately, human being does not. Human being is
incapable and do not possess such abilities, but robot can. Human can control with a
controller from a recliner at home while robot does the bidding in the world.
It is similar as a teleoperation system. Teleoperated robots are used where human is
not physically present in the environment. The common applications of teleoperation are
handling inaccessible or hazardous environment such as nuclear plant, deep underwater and
outer space. As the technology of teleoperation become more advanced, teleoperation is also
applied in medical surgeries. During surgery, the human operator operates the surgical tools
located at another room which is in a different location with patient to provide comfort for
the patient during the surgery. The human operator depends on the projected image of the
patient on a monitor and controls the position of the surgical tools. However, in order to
achieve minimally invasive surgery (MIS), the ability of human operator to sense the motion
in the teleoperation system is vital.
In the future, for robots and mechatronic system are required to support humans, they
should have a lot of abilities such as recognition of the real world based on human action,
and transmission of sense of touch of the environment based on human sensation. Thus, with
the ability to sense touch and manoeuvrability in teleoperation system, the human operator
2
can manipulate the environment as if the human operator is present in the environment. In
this case, during surgery, the human operator manipulates a surgical tool to cut a tissue of a
patient, the human operator is able to perform the task and at the same time sense the stiffness
of the tissue to avoid damage to the tissue and surrounding organs.
In fact, sensation from the environment is always a way to feel and recognize
everything that is touched. With auditory and visual information utilised together with the
haptic information, human can feel total immersion in augmented reality using Avatar robots
going to distance or unreachable places instead. In other words, unmanned aerial vehicles
(UAV) used for deep underwater exploration can implement haptic system to obtain haptic
information other than audio and visual information from the deep underwater environment.
In that case, the system must have interactivity for human operator to get information
from environment through bilateral control system. This means that the haptic information
from the real environment is only received when making contact with the real environment.
Thus, a bilateral control system with master and slave manipulator is needed to transmit the
information bilaterally. Each manipulator is equipped with actuators and sensors having one
or more degrees of motion freedom.
Further application of bilateral control system is micro-macro bilateral control
systems. The micro-macro bilateral control system consists of different size of master and
slave system. This system allows to transmit haptic information between different scaled
objects. Nevertheless, this system must able to scale the haptic information between the
master and slave system accordingly. Thus this allow operator to feel sensation as if they are
touching different scale of environment. It is also effective for application where operator
cannot manipulate directly.
Real-world haptic is the current attention not only as the principle of attaining real-
world haptic information in teleoperation but also the key technology for future human
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support. There are haptic fields that will expected to have great demand in our society. In
the next decade, haptic technology will become part of human’s compliant device for any
age of people and any occupations or professions. This includes human-support technologies,
medical/rehabilitation, exploration and industry. It will bring new technical issues in haptic
system.
1.1 Problem Statement
In particular, geared motor has been implemented vastly in industrial field such as
factory automation, robotics, industrial machine and medical sciences and laboratory
technology. Geared motor also brings cutting-edge technology application such as outer-
space and underwater exploration, advanced robotics, and machinery. The advantages of
geared motor are able to produce high torque. To produce a high torque out from a motor
itself without gear for power transmission, the size of the motor has to be big. This in fact
not just costly, but also impractical in size. Thus, it is important to realise that the higher the
torque required, the larger the size of the motor. With many different types of gears and
ratios, the engineer can decide the torque output required for an application.
However, in the past approaches, researches on bilateral teleoperation control system
utilised linear motor. The output force is powerful but the cost is high. Moreover, it controls
in linear position. Nevertheless, some researches approached bilateral teleoperation control
system using motor. But the output power is very low. For instance, the implementation of
geared motor in bilateral teleoperation control system is a new step in research. The outcome
of the teleoperation using geared motor able to realize a low cost teleoperation system.
Unfortunately, geared motor produces large joint friction in teleoperation and affects the
force/torque sensorless control.
4
Furthermore, industrial robots that seen in automation and car manufacturing industry,
the operation of the robots are programed based on trajectory position. Those usually are for
pick and place or assembly task. Yet, the operation area is fenced around to avoid human
access the operation zone. This is because the industrial robots are rigid and sensor-less to
external environment, thus it will harm and injured when it contacts with human during
operation. Consequently, these industrial robots are not safe during operation and not human
friendly. In order to be safer, accessible and human friendly, the system must have external
force feedback from the environment other than operation task. By all means if the system
able is to track external force, the industrial robots will halt the operation immediately when
it makes contact to undesired force from the environment.
Scaled teleoperation has been developed since decades ago. This which means the
physical and parameters of master and slave device are totally different. Even though
teleoperation systems used for human to operate larger scale slave manipulator such as
excavator, underwater UAV for exploration or maintenance purposes, these applications
have no haptic feedback information from the environment. In teleoperation between
different scale world, it is vital to consider the scaling effect in micro-macro bilateral control
system that able to provide the human operator with force feedback. In other words, it is
important to develop an effective method which can easily manipulate a different size
manipulator with scaling effect. Then the motion and force scaling are required for this
bilateral control system to realize physical support and manipulate in different scale of
environment. Thus, the micro-macro bilateral control system provides not just easy to
manipulate different size of master and slave device, also able to provide human operator
with a sense of haptic to a micro or macro environment as if it is in the same scale
environment.