Tese de doutoramento apresentada à Fac. de Ciências e Tecnologia da Universidade de CoimbraThe thesis is structured as follows:
• Chapter 2: Trajectory tracking problems are summarized.
• Chapter 3: Kinematic and dynamic modeling of theWMRs and car-like robots are presented.
• Chapter 4: The concept of sliding mode are first introduced. Then the fundamentals of SMC are summarized, including basic definitions, methods of sliding surface and control law design, robustness properties and the methods on handling chattering problems. New sliding-mode trajectory-tracking and slidingmode path-following controllers for WMRs and car-like vehicles, are also proposed in this chapter.
• Chapter 5: The trajectory/path planning are developed, including the velocity profile.
• Chapter 6: A model with two freedom degrees is considered for the HNC model. The user comfort is examined not only in the time domain, but also in the frequency domain.
• Chapter 7: Experimental results obtained with the implementation of the proposed controllers in RobChair are summarized and discussed.
• Chapter 8: Finally, conclusions are drawn and some suggestions for future work are provided
