DESIGN AND DEVELOPMENT OF A NEW
STABILIZATION MECHANISM FOR TWO-WHEELED
WHEELCHAIR
BY
TAREQ M. K. ALTALMAS
A thesis submitted in fulfilment of the requirement for the
degree of Master of Science (Mechatronic Engineering)
Kulliyyah of Engineering
International Islamic University Malaysia
JANUARY 2015
ii
ABSTRACT
This research embarks on designing a new mechanism for transforming a four-
wheeled wheelchair into a two-wheeled wheelchair. It is known that wheelchair
system is a main means of mobility for the disabled and the elderly. A normal four
wheels wheelchair has some limitations where the wheelchair user is too depending on
the helper, which reduces their mobility if the assistance is not available. The standard
wheelchair nowadays only caters for outdoor environment where the space is not a
constraint. Therefore, the two-wheeled wheelchair is proposed to encourage
independence where many common tasks such as pick and place things can be done
independently and is suitable to be used in confined space i.e. home, office or library.
The proposed two-wheeled wheelchair was modeled to mimics a double inverted
pendulum scenario where Link2 was introduced to cater for the human weight. To
increase the confidence level of the modeling stage, a virtual prototype of a two-
wheeled wheelchair was developed with a human model. Analysis of the model was
conducted and simulated to study the actuators requirement and response
performance. The mathematical models were then derived to represent the two-
wheeled wheelchair. It was achieved that the equations derived represents the system
as a highly nonlinear and unstable system. The complexity of the system was reduced
through the linearization of the equations. Both linearized and nonlinear equations of
motions were tested with different control strategies, where the LQR was
implemented on the linearized model and the fuzzy logic controller was designed to
control the nonlinear model of the two-wheeled wheelchair. Upon satisfactory results
of analysis on the virtual prototype and mathematical models with controllers, a full
hardware prototype was developed. The controllers designed were tested
experimentally and it provides promising results where the four-wheeled wheelchair
was able to transform into a two-wheeled wheelchair and stabilized at the upright
position as required.
iii
4
Link1 and Link2
LQRFuzzy logic
controller
.
iv
APPROVAL PAGE
I certify that I have supervised and read this study and that in my opinion it conforms
to acceptable standard of scholarly presentation and is fully adequate, in scope and
quality, as a dissertation for the degree of Master of Science (Mechatronic
Engineering).
……………………………….....
Salmiah Ahmad
Supervisor
………………………………….
Shahrul Na'im Sidek
Co-Supervisor
I certify that I have read this study and that in my opinion it conforms to acceptable
standard of scholarly presentation and is fully adequate, in scope and quality, as a
dissertation for the degree of Master of Science (Mechatronic Engineering).
………………………………….
Md. Raisuddin Khan
Examiner
………………………………….
Amir Akramin Shafie
Examiner
This dissertation was submitted to the Department of Mechatronics Engineering and it
is acceptable as a fulfilment of the requirement for the degree of Master of Science
(Mechatronic Engineering).
……………………………….....
Md. Raisuddin Khan
Head, Department of
Mechatronics Engineering
This dissertation was submitted to the Kulliyyah of Engineering and it is acceptable as
a fulfilment of the requirement for the degree of Master of Science (Mechatronic
Engineering).
………………………………….
Md. Noor Bin Salleh
Dean, Kulliyyah of Engineering
v
DECLARATION
I hereby declare that this dissertation is the result of my own investigation, except
where otherwise stated. I also declare that it has not previously or concurrently
submitted as a whole for any other degree at IIUM or other institutions.
Tareq ALTalmas
Signature……………………………. Date: …………………………
vi
INTERNATIONAL ISLAMIC UNIVERSITY MALAYSIA
COPY RIGHTS PAGE DECLARATION OF COPYRIGHT AND AFFIRMATION OF
FAIR USE OF UNPUBLISHED RESEARCH
Copyright © 2015 by Tareq ALTalmas. All rights reserved.
DESIGN AND DEVELOPMENT OF A NEW STABILIZATION
MECHANISM FOR TWO-WHEELED WHEELCHAIR
No part of this unpublished research may be reproduced, stored in a retrieval
system, or transmitted, in any form or by any means, electronic, mechanical,
photocopying, recording or otherwise without prior written permission of the
copyright holder except as provided below.
i. Any material contained in or derived from this unpublished research
may only be used by others in their writing with due
acknowledgements.
ii. IIUM or its library will have the right to make and transmit copies
(print or electronic) for institutional or academic purposes.
iii. The IIUM will have the right to make, store in a retrieval system and
supply copies of this unpublished research if requested by other
universities and research libraries.
Affirmed by Tareq ALTalmas
……………………..….. ……………….…..
Signature Date
vii
ACKNOWLEDGEMENTS
In the name of Allah, the most Gracious, the most Merciful. Praise be to the Almighty
Allah s.w.t, the God of the universe, for his mercy and blessings that have been
granted to the author. Peace and blessings be upon His messenger Muhammad s.a.w,
his families and companions.
My greatest appreciation and thanks to my project supervisor, Assoc. Professor
Salmiah Ahmed for her precious supervision, guidance as well as help and support
throughout this research. Her invaluable time and energy, idea and knowledge and
patience in guiding me to complete this research are appreciated. Many fields and
aspects have been explored and learned under her supervision.
I would like to dedicate this work to my family. My special thanks for my
father Maher and my mother Sanaa for their Doaa'. Also for my brothers Hossam,
Khalel, Abdullah and Mohammed. And finally for my sister Areej.
I would like to acknowledge the Ministry of Science, Technology and
Innovation (MOSTI) under the e-science fund for funding this project throughout my
study.
viii
TABLE OF CONTENTS
Abstract .................................................................................................................... ii Abstract in Arabic .................................................................................................... iii Approval Page .......................................................................................................... iv Declaration ............................................................................................................... v Copyright Page ......................................................................................................... vi Acknowledgements .................................................................................................. vii List of Tables ........................................................................................................... x List of Figures .......................................................................................................... xi List of Symbols ........................................................................................................ xv
CHAPTER ONE: INTRODUCTION .................................................................. 1 1.1 Introduction and Motivations ................................................................. 1 1.2 Problem Statement ................................................................................. 2 1.3 Aims and Objectives of the Research .................................................... 3 1.4 Methodology .......................................................................................... 4 1.5 Proposed Two-Wheeled Wheelchair ...................................................... 6 1.6 Thesis Outlines ....................................................................................... 7 1.7 Summary ................................................................................................ 8
CHAPTER TWO: LITERATURE REVIEW ..................................................... 9 2.1 Introduction ............................................................................................ 9 2.2 Inverted Pendulum ................................................................................. 10 2.3 Double Inverted Pendulum .................................................................... 12 2.4 Rotary Inverted Pendulum System ......................................................... 14 2.5 Two-Wheeled Mobile Robots ................................................................ 16 2.6 Wheelchair on Two Wheels ................................................................... 22 2.7 Commercial Two-Wheeled Robots ........................................................ 24
CHAPTER THREE: MODELING OF A TWO-WHEELED
WHEELCHAIR ..................................................................................................... 29 3.1 Introduction ............................................................................................ 29 3.2 Modelling of Two-Wheeled Wheelchair Using Solidworks .................. 30
3.2.1 SolidWorks Software .................................................................... 30 3.2.2 Two-Wheeled Wheelchair Virtual Prototyping ............................ 32 3.2.3 3D Full Assembly and Body Specifications ................................. 34 3.2.4 Mates Specifications ..................................................................... 36 3.2.5 Human Weight Representation ..................................................... 37
3.3 Mathematical Modeling of the Two-Wheeled Wheelchair ................... 38 3.3.1 Energy Derivation ......................................................................... 39 3.3.2 Euler-Lagrange Equation of Motion ............................................. 42 3.3.3 State Space Equations ................................................................... 43
3.4 Summary ................................................................................................ 44
CHAPTER FOUR: SIMULATION-BASED PERFORMANCE TESTING ... 46 4.1 Introduction ............................................................................................ 46
ix
4.2 SolidWorks Motion Simulations ............................................................ 46 4.2.1 Turning Diameter and Working Area ........................................... 47 4.2.2 System Behavior without Forces .................................................. 48 4.2.3 Required Torque analysis for Link2 ............................................. 49 4.2.4 Required Torque analysis of wheels' motors ................................ 52 4.2.5 Required Torque analysis from the Main Motors without
Tilting Mechanism ........................................................................ 54 4.2.6 Required torque analysis from the main motors with tilting
mechanism .................................................................................... 55 4.3 Open Loop Poles and System Response for two-wheeled
wheelchair Linear Model ....................................................................... 56 4.4 Control System Requirements for Balancing the System ..................... 57 4.5 System Controllability ........................................................................... 58 4.6 Pole Placement Design ........................................................................... 59 4.7 Linear Quadratic Regulator .................................................................... 61 4.8 Fuzzy Controller Design and Analysis .................................................. 65 4.9 Summary ................................................................................................ 70
CHAPTER FIVE: HARDWARE IMPLEMENTATION AND TEST ............. 71 5.1 Introduction ............................................................................................ 71 5.2 Physical Prototype Description .............................................................. 71 5.3 Drive system ........................................................................................... 73
5.3.1 Motor selection ............................................................................. 74 5.3.2 Brushless DC Motor: .................................................................... 76 5.3.3 Brushed DC Motor (BDC) ............................................................ 77 5.3.4 Motors in the system ..................................................................... 78
5.4 Sensors ................................................................................................... 83 5.4.1 Inertial measurement unit (IMUs) ................................................. 84
5.5 Power system ......................................................................................... 88 5.6 Data Acquisition System (DAQ) ........................................................... 88 5.7 Main motors Analysis ............................................................................ 90 5.8 Experimental analysis of Fuzzy controller ............................................. 91 5.9 Summary ................................................................................................ 94
CHAPTER SIX: CONCLUSION AND RECOMMENDED WORK ............... 96 6.1 Conclusion .............................................................................................. 96 6.2 Contributions .......................................................................................... 97 6.3 Recommendation for further work ......................................................... 98
REFERENCES ....................................................................................................... 99
APPENDIX A PUBLICATIONS ........................................................................ 103 APPENDIX B INPUT AND OUTPUT USER INTERFACE OF SBDM-25A .. 104 APPENDIX C SPECIFICTIONS LIST OF THE BDC MOTOR DRIVER ....... 105 APPENDIX D PINS FUNCTIONS OF FD04A DC MOTOR DRIVER ............ 106 APPENDIX E TRUTH TABLE TO CONTROL THE DIRECTIONS OF
THE MOTORS ............................................................................ 107 APPENDIX F SENSOR SPECIFICATIONS ..................................................... 108 APPENDIX G MODULES THAT ARE USED AND ITS FUNCTIONS .......... 109
x
LIST OF TABLES
Table No. Page No.
4.1 If – then rules for the fuzzy controller (𝑒1, ∆𝑒1, 𝑒2, ∆𝑒2,) 68
5.1 Gains for the Input and output of the Fuzzy logic controller 92
xi
LIST OF FIGURES
Figure No. Page No.
1.1 Research methodology flowchart 5
2.1 Schematic diagram of inverted pendulum system on cart 10
2.2 Inverted pendulum systems on rail. 11
2.3 Schematic diagram of double inverted pendulum system with joint 13
2.4 Rotary inverted pendulums 15
2.5 Two-wheeled mobile robot 16
2.6 New configuration of two-wheeled vehicle with extendable link 19
2.7 Two-wheeled mobile robot for transporting human and good 20
2.8 Two-wheeled inverted pendulum robot 21
2.9 Visual nastran model of the wheelchair with human model 23
2.10 iBOT two-wheeled wheelchair 25
2.11 Segway® personal transporters 26
2.12 Personal urban mobility and accessibility (puma) 27
2.13 Genny two-wheeled wheelchair 27
3.1 Bottom-up assembly design approach flowcharts 31
3.2 The frame of the wheelchair (link1) 32
3.3 Scissor sub assembly (link2) 33
3.4 Caster subassembly 33
3.5 Driving wheel of the wheelchair 34
3.6 Full 3d model of the two-wheeled wheelchair 34
3.7 Occupied length by the wheelchair 35
3.8 Occupied width by the wheelchair 35
3.9 The highest level after raising the scissor lift 36
xii
3.10 The lowest level before raising the scissor lift 36
3.11 The two-wheeled wheelchair with approximated human weight. 38
3.12 Schematic diagram of two-wheeled wheelchair 39
4.1 Turning diameter of two-wheeled wheelchair 47
4.2 Initial situation of the free forces test 48
4.3 Angular displacement of the two-wheeled wheelchair virsus time 48
4.4 Schematic diagram of the link2 49
4.5 Applied motion profile on the motor of the link2 50
4.6 Change of center of mass position of the Link2 51
4.7 Calculated torque based on the Eq. 4.5 51
4.8 Required torque for tilting Link2 from SolidWorks motion
simulation 52
4.9 (a) Wheelchair on four wheels (b) Wheelchair on two wheels 52
4.10 Required torques from the main motors when casters on the ground 53
4.11 Required torques from the main motors when casters is not on the
ground 53
4.12 The initial situation of the wheelchair to calculate the required
torques 54
4.13 Applied profile motion on the motors 54
4.14 Required torques from the motors without using tilting mechanism 55
4.15 Initial condition of the wheelchair with tilting mechanism 56
4.16 Required torques from the main motors after introducing tilting
mechanism 56
4.17 Open loop response for the two-wheeled wheelchair system 57
4.18 Block diagram of pole placement control design 59
4.19 Step response of the two-wheeled system with pole placement 61
4.20 Schematic diagram of the system with lqr 62
4.21 Step response of the two-wheeled system with (LQR) 63
xiii
4.22 Step response of the two-wheeled system after applying lqr with
tuned Q 64
4.23 Block diagram of a PD-like fuzzy control system for link1 and link2 66
4.24 Multi-input single-output balancing of FLC1 66
4.25 Multi-input single-output balancing of FLC2 66
4.26 Membership functions for the inputs error1(𝑒1) and error2 (𝑒2) and
change of error1(∆𝑒1) and change of error2 (∆𝑒2) 67
4.27 Membership functions for the outputs 67
4.28 Control scheme for simulating the nonlinear mathematical model 68
4.29 Angular position of Link1 𝜃1 versus time 69
4.30 Angular position of Link1 𝜃2 versus time 69
5.1 The two-wheeled wheelchair hardware design 72
5.2 Eye- to eye conversation outcome 72
5.3 Brushless dc motor diagram 77
5.4 Two basics design of brushless dc motor 77
5.5 Brushed dc motor diagram 78
5.6 Main motor of the system 79
5.7 Motor for tilting Link2 80
5.8 Warm gear reducer that is attached to the tilting motor 80
5.9 Sbdm-25a brushless dc motor driver 81
5.10 Input and output pins of the driver sbdm-25a 81
5.11 Connection diagrams of the pins 6, 7 and 8 81
5.12 Connection diagram of the speed control 82
5.13 FD04A dc motor driver 82
5.14 Pins orientation of FD04A dc motor driver 83
5.15 SV-IMU5D-LC IMU unit 85
5.16 The measured angle from the gyroscope under static situation 86
xiv
5.17 The measured angle from the gyroscope under rotating situation 86
5.18 The measured angle from accelerometer under static situation 87
5.19 The measured angle from accelerometer under rotating situation 87
5.20 Golden motor battery 88
5.21 The typical pc-based DAQ system 89
5.22 cDAQ-9188 chassis 89
5.23 C-modules that is used as input/output for the controller 90
5.24 Applied voltage on the main motor driver 91
5.25 Feedback from the motor driver in Hz 91
5.26 Block diagram of a pd-like fuzzy control system for link1 and link2 92
5.27 Angular position of Link1, and the angular position error, versus
time 93
5.28 Angular position of link2, and the angular position error, versus time
94
xv
LIST OF SYMBOLS
𝐽𝑅 Moment of Inertia of the Right Wheel
𝐽𝐿 Moment of Inertia of the Left Wheel
𝐾𝑅 Kinetic Energy of the Right Wheel
𝐾𝐿 Kinetic Energy of the Left Wheel
𝐾1 Kinetic Energy of Link1
𝐾2 Kinetic Energy of Link2
𝐾𝑡 Total Kinetic Energy of the System
𝐿1 Length of Link1
𝐿2 Length of Link2
𝑀𝑅 Mass of the Right Wheel
𝑀𝐿 Mass of the Left Wheel
𝑀1 Mass of Link1
𝑀2 Mass of Link2
r Radius of the Wheels
R Angular Displacement of the Right Wheel
𝜃�̇� Angular Velocity of the Right Wheel
R Angular Acceleration of the Right Wheel
L Angular Displacement of the Left Wheel
𝜃�̇� Angular Velocity of the Left Wheel
L Angular Acceleration of the Right Wheel
1 Rotation Angle of Link1
𝜃1̇ Angular Velocity of Link1
xvi
1 Angular Acceleration of Link1
2 Rotation Angle of Link2
𝜃2̇ Angular Velocity of Link2
2 Angular Acceleration of Link2
𝑈𝑅 Potential Energy of the Right Wheel
𝑈𝐿 Potential Energy of the Left Wheel
𝑈1 Potential Energy of Link1
𝑈2 Potential Energy of Link2
𝑈𝑡 Total Potential Energy of the System
x Linear Position of the Wheelchair
𝑋𝑅 , 𝑌𝑅 The Position of the Right Wheel in the x-y Plane
�̇�𝑅 , �̇�𝑅 The Velocity of the Right Wheel in Regard to the x-y Plane
𝑋1, 𝑌1 The Position of the Link1 in the x-y Plane
�̇�1, �̇�1 The Velocity of the Link1 in Regard to the x-y Plane
𝑋2, 𝑌2 The Position of the Link2 in the x-y Plane
�̇�2, �̇�2 The Velocity of the Link2 in Regard to the x-y Plane
1
CHAPTER ONE
INTRODUCTION
1.1 INTRODUCTION AND MOTIVATIONS
Wheelchair is a device used for mobility of the people for whom walking is difficult
or impossible, due to illness or disability. Wheelchairs have many types and versions,
emese rehe wheelchairs are propelled manually (manual wheelchair), while others
move by actuating motors (electric wheelchair).
The population of wheeled mobility device users has increased by 4.3% per
year, and there are about 3.3 million adults using these devices (LaPlante and Kaye,
2010). The use of wheelchair has helped disabled people to be more independent in
their life, which increases the vocational and educational opportunities, reduces
dependence on caregivers and family members, and promotes feelings of self-reliance
(Simpson, 2005). On the other hand, it is very obvious that the user of a normal
wheelchair needs an assistant for their mobility, thus the contributions of those normal
people in the society are affected (Simpson, 2005). There are many types of
wheelchairs that have been designed with special functions. Some of the designs give
the ability to climb over step and curbs (Cooper, et al., 2012), while, others are
derigned te melp ures’r hebility in tme reciety. In pasticular, there was a wheelchair
designed to help user to have face to face conversation with people by lifting the seat
(INDEPENDENCE® iBOT® 4000 Mobility System, 2013). This two-wheeled
wheelchair was invented to give the user the ability to maneuver in confined space.
The lifting mechanism that was designed has the ability of increasing the seat level
2
help the user to act independently, for instance to pick and put things on the shelves in
the library and home.
Disabled and aged people have been using wheelchairs widely for the sake of
mobility since the wheelchairs have become an important assistive tool for them. The
works on invention wheelchairs with extra features have grown rapidly as the industry
of wheelchairs evolve. The field of improving the wheelchair’s features focuses
particularly on tme emeelcmais’r featuser rucm ar derign, tsaveling sange, rtyle, control,
maneuverability, seating, suspension system, and other functions. In fact the
increasing number of wheelchair users with different needs has been motivating the
researches and industry to produce more new designs with extra features.
Two-wheeled wheelchair system is proposed in this research having a unique
function to fulfill the needs among the wheelchair users. The system is designed such
that it has the mechanism of converting its original four-wheeled wheelchair to the
two-wheeled wheelchair with the ability of lifting the seat to give the wheelchair users
more independence during their daily activities and the user may have face-to-face
conversation with other normal people, which indirectly has significant effect on their
emotional and psychology.
1.2 PROBLEM STATEMENT
As mentioned that the number of wheelchair users increases day by day. Therefore,
the need of producing improved products that offer a greater independence and greater
participation in the family and community is also increased. The proposed design will
give the disabled people the desired independence in their daily life.
Nakamura & Murakami, (2009) listed three problems in the structure of the
available four-wheeled wheelchairs. Firstly, the requirement space to turn and move
3
the manual wheelchair needs more space and to make 360 degree turn it need go
forward and backward. Second problem is the resistance of the front wheels. Thirdly,
the seat level which it is not provided face to face conversation with normal people.
(Why Choose Genny, 2012) listed some difficulties for traditional wheelchair users.
Firstly, the casters problem which the users have to take care constantly to prevent it
stuck into little holes or cracks in the pavement. Moreover, the normal wheelchair
users have to keep holding the wheels. The iBOT design has some limitations. It has
the ability to work and balance on two wheels, reach face to face conversation level
and climb stair. But unfortunately, this product is not available currently on the
markets. Genny mobility is another tee emeeled vemicle but it deern’t mave tme ability
to maintain the seat level.
Consequently, the need for two-wheeled mobile vehicle has grown and
attracted many researchers to conduct their researches in this field to come out with
new products that help wheelchair users to be independent as much as possible. These
products have the ability to move and balance on two wheels and maintain the height
of the seat which gives wheelchair users much independence in their daily life.
Therefore, this research on the design and development of a new mechanism of two-
wheeled wheelchair for disabled.
1.3 AIMS AND OBJECTIVES OF THE RESEARCH
The objectives of this research are as follows:
1. To model and develop prototype of a wheelchair system that mimics a
double inverted pendulum scenario.
2. To design a new mechanism for transforming a normal four-wheeled
wheelchair into a two-wheeled wheelchair.
4
3. To design suitable lifting mechanism to increase the height of the seat.
4. To confirm stability of the wheelchair during its motion.
5. To perform hardware implementation of the wheelchair system and
evaluate the performance experimentally.
1.4 METHODOLOGY
To achieve the goal, this research started with conducting reviews and surveys on the
previous designs and works that have been done on the similar issue. Then, different
modeling techniques were used to model the new mechanism for converting a normal
wheelchair on four wheels onto a two-wheeled wheelchair. Then the analyzing stage
taker place emese tme ryrteh’r hecmanirh derigned in tme vistual 3D envisenhent ir
tested. The wheelchair hardware is then realized based on the designed parameters of
the model. Then, the hardware design tested with fuzzy logic controller. This research
intends to help wheelchair users to act independently in their life. Figure 1.1 shows the
research methodology flowchart.
5
Figure 1.1 Research methodology flowchart
6
1.5 PROPOSED TWO-WHEELED WHEELCHAIR
Two-wheeled wheelchair is a complex, highly nonlinear but yet is an interesting and
challenging system to be designed and controlled. It is important to build a proper
design and control strategy to keep this complex system balanced, stable and perform
as similar as normal wheelchair does. Two-wheeled wheelchair is aimed to be suitable
for domestic areas and confined spaces that it will take less space comparing to the
normal four-wheeled wheelchair, particularly during steering process. This is due to
its ability to turn into spot, similar to any mobile robot on two wheels.
This research focuses on developing a new design and mechanism for
transforming normal four-wheeled wheelchair onto a two-wheeled wheelchair by
rising up the front wheels (casters) of the wheelchair. Furthermore, a scissor
mechanism is introduced to change the seat’r height to reach higher level of heights.
This research is aimed to assist the wheelchair users to have independent life. The
encouragements on the proposed wheelchair on two wheels, which mimics a double
inverted pendulum scenario, are:
1. To provide the wheelchair users the ability to maneuverable in confined
spaces such as house, library or offices particularly during the sharp
cornering.
2. To equip the user with the ability to reach higher level of height that will
help them in picking and placing things on shelves and allowing them to
have an eye-to-eye level during conversation with a standing normal
people.
7
1.6 THESIS OUTLINES
The outlines of the thesis are explained as follows;
Chapter One: This chapter introduces and explains the importance of the
wheelchair for disabled and elderly people as a tool for mobility. Then it covers the
problem statement, aims and objectives, methodology, and the proposed design.
Chapter Two: This chapter summarizes a list of previous works that is related
to this research. Inverted pendulum, double inverted pendulum, rotary inverted
pendulum, and then previous researches, and designs have been discussed in this
chapter.
Chapter Three: This chapter discusses a wheelchair 3D model. The process of
3D modelling from part building until full assembly has also been described. This
chapter further presents the mathematical modelling of the proposed two-wheeled
wheelchair system based on Lagrangian approach. Non-linear equations of motion
have been derived then they have been linearized to get the linear state space model.
Chapter Four: This chapter presents the SolidWorks motion simulation, that
simulation has been used to show the turning diameter of the design and system
behavior when raising the casters. It is used also to calculate the required torques from
the Link2 and the effect of using the Link2 in the system. The effects of removing the
casters have also been explained. The open loop step responses of the linear state
space model. Control system requirements have been explained. Moreover, system
controllability has also been tested. The system has been tested with pole placement
approach and linear quadratic regulator (LQR). Further, it is discusses the
implementation of fuzzy logic control on the nonlinear model.
8
Chapter Five: This chapter describes the physical prototype of the two-
wheeled wheelchair system. Then the actuator, power sources and the sensor system
have been discussed as well. In addition, the used data acquisition system and
interfacing has been presented. It is also shows the system behavior after
implementing two independent fuzzy logic controller for each link.
Chapter Six: The conclusions of this work, contribution of research and the
recommendations for further work and improvement have been explained in this
chapter.
1.7 SUMMARY
This chapter has briefly described the introduction and the motivations of the research
of the two-wheeled wheelchair. Then a brief explanation about the proposed design
has been written with the benefits of using two-wheeled wheelchairs system with the
ability ef cmanging tme reat’r meigmt. The aims, objectives, problem statement and
research methodology of the research have been described.