DEVELOPMENT AND CONTROL OF AN UNDERACTUATED TWO-WHEELED MOBILE ROBOT

Abstract

This thesis presents the design of linear and nonlinear control algorithms for an underactuated two-wheeled mobile robot (2WMR). A 2WMR prototype is developed and used to demonstrate and verify the effectiveness of the proposed control algorithms. Considering that various uncertainties exist in the real time 2WMR system, robustness is addressed in the control system design. Linear controller is simple and easy to implement, however, provides limited robustness. Nonlinear controllers such as sliding mode control (SMC) or fuzzy logic control (FLC) are robust. However, a major difficulty in the design and implementation of the nonlinear controllers is the determination and tuning of the controller parameters. To avoid the difficulty in the nonlinear controller design, synthesized designs of linear and nonlinear control techniques are proposed. The nonlinear controller parameters are determined based on the knowledge of a linear controller, which makes the nonlinear control design become simple, systematic and easy to implement. Furthermore, the feedback gains for the linear controller are free to be chosen, thus an extra degree of freedom is obtained in control.