Motion control and stabilization of a Skid-Steering Mobile Robot

In this paper, motion control and stabilization of a 4-Wheel Skid-Steering Mobile Robot (4WSSMR) are studied. A ratio controller which has been successfully applied in the chemical industry is designed to limit the vehicle lateral skid. Motion stability is guaranteed by generating an appropriate steering action (driving bias in left and right wheels) according to the states of the vehicle. A model free High Order Differential Feedback Controller (HODFC) cooperates with the ratio controller for motion control. In the proposed model-free scheme vehicle states used by the ratio controller and HODFC are estimated by high order differential (HOD) observer. Different road surface scenarios with varying frictional coefficients are designed to test performance and the ability to reject disturbances and noise. Trajectory tracking simulation results show that the proposed is robust to uncertainties and performs well even if some parameters are unknown.