Backstepping Fuzzy Sliding Mode Control for a Three-Links Spatial Robot Based on Variable Rate Reaching Law

To achieve the tracing control of a three-links spatial robot, a backstepping fuzzy sliding mode controller based on variable rate reaching law is proposed in this paper. The sliding mode controller is designed by means of backstepping way. To reduce the adjustment time, a fuzzy controller is designed to adjust the slope of sliding mode surface. To diminish the chattering of traditional sliding mode control, the variable rate reaching law is proposed. The variable rate reaching law is composed of the distance from current point to sliding mode surface in phase plane. The simulation studies for the tracking control of a three-links spatial robot have been carried out. Simulation results show the validity of the proposed control scheme.