Sliding mode line-of-sight stabilization of two-axis photoelectric platform

The PID controller is widely used in two-axis photoelectric platform velocity loop, however the control precision and the stability of controller are contradictory, especially when friction torque is added. In order to solve this problem, the characteristics of PID controller were analyzed detail in this paper, then a sliding mode controller was designed based on the approach law. First, the model of two-axis photoelectric platform velocity loop was established, then the friction model was linearized according to the interval analysis theory, after that the sliding mode function and the controller was designed, next the simulation model was build, finally, the performance of the velocity loop was compared between sliding mode controller and PID controller, the results showed the sliding mode controller has higher control precision and the stability.