Double-segment sliding mode control for permanent magnet synchronous motor servo drives

This paper proposes a double-segment sliding mode control method in accordance with an exponential velocity profile for a high precision three-axis AC servo system used for industrial production. The newly designed sliding mode controller is composed of the velocity segment and the position segment. Global sliding mode control is used in the velocity segment so that the velocity along the sliding surface can exponentially accelerate from 0 to a constant velocity determined by the given position. Integral sliding mode control is adopted in the position segment to improve the position accuracy. In order to reduce the chattering and enhance the robustness of the system, the fuzzy inference is introduced to obtain the switching control laws. Several simulation results are provided to demonstrate the validity of the proposed method.