Sliding Mode Control of Servo Motor Based on Novel Reaching Law

A new type of exponential rate is proposed, in order to improve the dynamic quality of servo motor speed control system. The reaching law relates the approach speed to the change of the system state quantity, which overcomes the shortcomings of the conventional exponential approach rate. The inherent buffeting problem of the sliding mode is effectively suppressed. The reaching law is applied to the servo motor speed control system, and a sliding mode variable structure speed controller based on a novel exponential reaching law is designed to replace the traditional PI regulator. Simulations and experiments show that the speed controller is robust to system parameters uncertainties, external disturbances and noise, and it can effectively improve the dynamic and static characteristics of the system. This makes the servo motor can be better applied to the robot servo system.