Sliding mode control for tracking of nonholonomic wheeled mobile robots

A chatter-free sliding mode controller employing only conventional sliding surfaces is proposed for trajectory tracking of a nonholonomic wheeled mobile robot. In one sliding surface, nonlinear state variable coupling is avoided by linearly combining two indirectly controlled states into a single aggregate variable. This greatly simplifies analysis compared to the case of sophisticated sliding surfaces. The derived control signals are in form of their respective time derivatives. Thus, upon integration, continuous control action is actually produced, yielding significant chatter reduction. Rigorous stability proofs as well as validation simulation results are presented.