音圈快速反射镜的完全跟踪控制

Perfect tracking control for fast-steering mirror driven by voice coil motor

音圈电机驱动的快速反射镜在传统控制方法下具有严重的相位滞后,限制了其性能。针对这一问题提出了一种完全跟踪控制方法(Perfect Tracking Control,PTC)。首先,建立音圈快速反射镜系统离散状态空间模型,构建多速率采样系统,对长周期采样控制环节设计完全跟踪控制器;然后,对短周期环节设计基于离散滑模变结构控制的内回路补偿控制器。新方法实现了音圈快速反射镜对指令的完全跟踪,并有效补偿了外部扰动、模型不确定性以及机械非线性等因素对系统性能的影响,保证了系统的鲁棒性。实验结果表明PTC控制实现了系统工作频带的扩展,与传统PID控制相比,系统的阶跃响应调节时间缩短50%,静态位置波动峰峰值减小50%;与基于干扰观测器和零相差跟踪控制器的方法相比,系统的位置稳态误差由1.5%减小到0.05%。采用新方法的音圈快速反射镜对幅值360″的正弦位置指令跟踪的双十带宽达到375 Hz,有效改善动态性能,拓展控制带宽。

The traditional control method for a fast-steering mirror driven by a voice coil motor suffers from serious phase lag,which limits the performance.Herein,a perfect tracking controller(PTC)was proposed to solve this problem.First,a discrete state space model of the voice coil-driven fast-steering mirror was established,a multirate sampling system was constructed,and a PTC was designed for long-cycle operations.Second,an internal compensator controller was designed for short-cycle operations based on the discrete-time sliding mode control method.The new method achieves perfect tracking of the voice coil-driven fast-steering mirror and reduces the effects of external disturbances,model uncertainties,and mechanical nonlinearity,thus ensuring the robustness of the system.Experimental results show that the proposed PTC improves bandwidth performance.Compared with the proportional-integral-derivative controller method,the system step response time is reduced by 50%and position error is reduced by 50%.Compared with the disturbance observer and zero phase error tracking controller method,the steady-state error is reduced from 1.5%to 0.05%.Moreover,the proposed method allows the fast-steering mirror driven by a voice coil motor to track sine position commands with an amplitude of 360″;the double-decade bandwidth is up to 375 Hz.The proposed method can effectively improve dynamic performance and expand the system control bandwidth.