MODELLING AND CONTROL OF A NONHOLONOMIC MOBILE ROBOT
MOHD ZAFRI BIN BAHARUDDIN
A dissertation submitted in partial fulfilment of the
requirements for the award of the degree of
Master of Engineering (Electrical – Mechatronics and Automatic Control)
Faculty of Electrical Engineering
Universiti Teknologi Malaysia
MAY 2008
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DEDICATION
For my loving wife
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ACKNOWLEDGEMENTS
All praise to Allah the Almighty. Many people including academicians,
family and friends have assisted me. They have contributed much to my progress in
this project in terms of guidance and moral support. In particular I would like to
express my deepest gratitude to Prof. Madya Dr. Mohamad Noh Ahmad for his
leadership and direction in guiding me through this project till now. The project
would not have progressed this far without his encouragement and vision.
I would also like to thank Universiti Tenaga Nasional for funding my
continuing study at Universiti Teknologi Malaysia. Particular staff members whom I
would like to thank are Hj. Abdul Aziz Bin Hj. Mohamed Yusof and Cik Nazimah
Mohd Mokhtar from Human Resource, Syed Sulaiman, Dr. Izham Zainal Abidin,
Adzly Anuar and all members of the UNITEN Mobile Robotics Group for their
continued efforts and interest in mobile robotics.
Family and friends that constantly push me to complete this project on time,
colleagues, course mates and even students that know me have all helped in various
ways to contribute to this project. Also not forgetting all my lecturers in my masters
course who have inspired me to do better every time. I am grateful to each and every
one of them and I would like to express a big thank you.
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ABSTRACT
Mobile robots are becoming more common in today's fast growing
environment. Its extensive study and research have become a major part in the
mobile robot's rapid development.
An effective method of development is via
modelling tools and computerized simulations.
In this project, kinematic and
dynamic models of a nonholonomic two-wheeled mobile robot were simulated with
its behaviour defined by a controller. The robot defined in this project has two
actuated wheels while any other contact with the surface travelled is assumed to be
frictionless. This project identifies two robot controllers, which are the proportionalintegral-derivative (PID) control and pole placement methods. These control
methods are implemented via the MATLAB/Simulink software into the kinematic
and dynamic models of the robot. Controllers were chosen according to its robot
model that conforms to the standard robot designed in this project. The tracking
control method of each controller was also studied to ensure stability of the model.
In the simulation, the robot is given several predetermined paths. The robot does not
know these paths and it has to be able to adapt and react to different paths. The
controller is considered successful when it can follow the predetermined path
accordingly and effectively. Through the simulations, these controllers are studied
and compared.
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ABSTRAK
Robot bergerak kini menjadi perkara lazim di dalam persekitaran moden
yang semakin rancak.
Pengajian dan penyelidikan oleh pelbagai pihak
membolehkan [area] robot bergerak ini dibangunkan dengan pesat.
Salah satu
kaedah pembangunan yang kos efektif adalah melalui pemodelan matematik bersama
simulasi berkomputer. Model kinematik dan dinamik robot bertayar dua disimulasi
dengan sifat-sifatnya diserapkan oleh sebuah pengawal digital. Robot dalam projek
ini mempunyai dua tayar bergerak manakala bahagian lain yang bersentuh dengan
permukaan lantai dilihat sebagai tidak mempunyai geseran. Projek ini mengenalpasti
dua pengawal digital iaitu pengawal Berkadar Terus – Kamiran – Terbitan atau
Proportional-Integral-Derivative (PID) dan [pole placement].
Teknik-teknik
kawalan ini diimplimentasi menggunakan perisian MATLAB/Simulink ke dalam
model kinematik dan dinamik robot tersebut. Pengawalan digital dipilih mengikut
model robot yang didapati. Teknik kawalan jejakan bagi setiap pengawal digital
dikaji bagi memastikan kestabilan model. Dalam simulasi ini, robot diberi sasaran
perjalanan yang ditentukan terlebih dahulu. Robot ini perlu mengadaptasikan dirinya
dan bertindak dengan sesuai mengikut sasaran yang berbeza.
Pengawal robot
dianggap berjaya apabila ia mampu mengawal robot untuk mengikut sasaran
perjalanan tersebut. Perbezaan antara pengawal-pengawal ini dikaji dan dibandingi.