基于滑模变结构控制及预测跟踪的光电吊舱控制方法

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

光电吊舱在稳像和目标跟踪过程中存在摩擦力矩、不平衡力矩等干扰力矩,从而影响速度环响应精度;另一方面,吊舱视频跟踪器图像传输和处理造成的延迟也会造成跟踪滞后,因此必须进行延时补偿。提出基于预测跟踪的滑模变结构控制方法,采用微分预测跟踪器实现对视频跟踪器的延迟补偿,采用预测跟踪器估计出的目标运动角速率构成自适应补偿参数,以调整滑模变结构控制量,改进的滑模控制算法在补偿干扰力矩的同时抑制了抖振现象。仿真及实验结果表明:改进的控制方法能够有效补偿干扰力矩和跟踪器延迟造成的误差,相对于传统PID控制,其跟踪误差减小为原来的1/3,并且该算法已经在相关系统上得到应用。

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.