Path-following control for multi-axle car-like wheeled mobile robot with nonholonomic constraint

This paper deals with the path-following control of multi-axles driving car-like wheeled mobile robot (WMR). Addressing the issues of the nonholonomic constraint characters of the WMR, firstly, this paper analyzes the steering relationship of geometry and kinematical constraint of the multi-axles driving WMR, and establishes the dynamical equations. Then, using the guidance law that based on the guidance-based path-following principle to evaluate the tracking errors, the attitude angle for eliminating the tracking errors and updating law for path parameters are deduced. By stability analysis, the global uniform asymptotic stability of the system is certificated. Furthermore, the linearization robot dynamic model is derived by means of the nonlinear feedback linearization strategy. In order to overcome the torque disturbance, a sliding mode speed tracking controller with disturbance observer is proposed based on this linearization dynamic model. The simulation of tracking performance with the planned desired path which is constructed by cubic spline interpolation method is performed. The simulation results show that the proposed control strategy can achieve satisfactory path-following control performances.