A trajectory tracking control design for a skid-steering mobile robot by adapting its desired instantaneous center of rotation

A skid-steering mobile robot steers by creating a moment that is larger than the frictional moment which results in a lateral slippage also known as skidding. This moment is in turn generated by a difference of the forces originated from the two sides of the robot. Tracking a given trajectory using this type of steering mechanism is not easy since it requires to relate skidding to steering. A necessary condition for the stability of skid-steering mobile robots is that the longitudinal component of the instantaneous center of rotation (ICR) resides within the robot dimension. In the present work, we propose a novel trajectory-tracking control design using a backstepping technique that guarantees the Lyapunov stability and that satisfies this necessary condition by relating the longitudinal component of the “desired ICR” to the curvature of a given trajectory and the reference linear speed. Finally, we compare the performance of the proposed controller to that of other existing controllers for skid-steering mobile robots and show the robustness of the proposed controller even in the presence of modeled sensory noise and control time delay in simulation.