为了满足光学精密工程中光束方向控制执行机构-大口径快摆镜机构(LAFSM)高精度的控制要求，对LAFSM结构特性、系统辨识方法以及其实验平台构建、控制器参数优化等进行了研究。首先详细分析了LAFSM系统组成、结构及电学特性，推导出系统模型的结构类型，建立了LAFSM系统辨识方法，搭建了实验平台。此方法剔除了数据采集系统本身对系统辨识的影响，有效减弱了背景噪声的干扰，得出了精确的系统数学模型，在小于40 Hz范围内，幅频特性误差小于0.8 dB，相频误差小于1°。根据精确的数学模型设计了PID控制器，采用广义Hermite-Biehler定理计算出使LAFSM闭环系统稳定的比例、积分、微分系数的取值范围，运用遗传算法对PID参数进行整定和优化，消除系统的振动、超调及稳态误差，使响应时间控制在0.2 s以内，系统稳态误差为0。实验和仿真证明，本系统辨识方法可靠可行，精度高；控制器参数优化方法快速高效，控制效果良好。%In order to meet the precision control requirements of large-aperture fast steering mirror mechanism (LAFSM) in optics and precision, the structural characteristics, experiment platform and control method of LAFSM and system identification methods are studied. Firstly, the support structures of the LAFSM, the structural and electrical properties of various components are analyzed. Then the structure of the model in theory is derived. Based on this, the system identification method of the LAFSM and an experiment platform are designed. This method excludes the effect of data acquisition system upon system identification, and the background noise interferences are weakened to a certain extent. Then the precise mathematical model of the LAFSM is derived. In 40 Hz range, the amplitude-frequency characteristic error is less than 0.8 dB, and the phase-frequency error is less than 1°. After that, the PID controller design is completed. The range of proportional, integral and differential coefficients, which make the closed-loop system stable, are calculated based on Hermite-Biehler theorem. After all, the PID parameters are tuned and optimized by using the genetic algorithm. It is proved that the controller significantly eliminate the vibration, overshoot and steady-state error, the response time is less than 0.2 s, and the system steady-state error is 0. Experiments and simulations show that this system identification method is stable, reliable, and high precision. The proposed optimization method of controller parameters is fast and efficient.
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