针对空间光通信中捕获、瞄准和跟踪(ATP)技术的精跟踪系统对信标光斑实时准确跟踪需求,设计了基于前馈补偿的比例,积分和微分(PID)模糊控制系统,采用camera-link接口的高帧频CMOS相机和大规模FP-GA芯片设计了精跟踪处理控制平台,并将图像处理、前馈补偿和PID模糊控制等功能全部集成在FPGA芯片内部。实验结果表明,前馈补偿模糊PID控制具有更强的系统适应性,精跟踪系统带宽达到300 Hz,对大于100 Hz的高频振动频谱仍然有很好的抑制补偿效果,尤其对于低于60 Hz的主要扰动频谱具有很好的跟踪补偿效果,抖动压缩比达到90%以上,抖动均方差小于1 pixel,定位精度约为1μrad。
In order to track the beacon facular accuratly and real time for fine tracking system in free space optical communication,a set of fuzzy proportional integral and derivative(PID)control system based on feed-forward compensation is designed,the fine tracking control platform is developed by adopting CMOS camera with camera-link interface and large scale FPGA chip,and the function modules such as image processing,feed-forward compensation and fuzzy PID algorithms are all integrated into FPGA chip.Fuzzy PID integrated with feed-forward compensation improves the control precision and enhances the anti-jitter ability of nonlinear system greatly.Experiment result demonstrates that with the same frequency,fuzzy PID control with feed-forward compensation has better adaptability for nonlinear system compared with the traditional PID control and with different frequency,the bandwidth of fine tracking system is up to 300 Hz.The system has fairly good compensation effect for the vibration frequency which is higher than 100 Hz,especially for the main spectrum within 60 Hz.The vibration reduction ratio is higher than 90%,the vibration mean square error is less than 1 pixel,and the location precision is approximate 1 μrad.