Photoelectric pod control method based on sliding mode variable structure control and prediction tracking

There exist friction torque, unbalanced torque and other disturbance torques in the process of image stabilization and target tracking by photoelectric pod, which affect the response accuracy of speed loop. On the other hand, the delay caused by the image transmission and processing of the pod video tracker can cause tracking lag. Therefore, the delay must be compensated so as to reduce the error. For this, a sliding mode variable structure control method based on prediction tracking was proposed, in which the differential prediction tracker was adopted to compensate the delay of video tracker, and the motion angular velocity of target estimated by the prediction tracker was applied to compose the adaptive parameter so as to adjust the quantity of sliding mode variable structure contro. The improved sliding mode control algorithm could compensate the disturbance torque and suppress the chattering phenomenon at the same time. The simulation and experiment results show that the improved control method can effectively compensate the errors caused by disturbance torque and delay of tracker , its tracking error is reduced to 1/3 of the original traditional PID control.What's more, the proposed method has been applied in related systems.