由于高精度位移传感器体积大、价格高，系统传递函数复杂难以辨识等因素，目前对于压电驱动的FSM 大多通过前馈补偿的方法进行开环控制。为了实现对一种新型三支撑三维FSM 的反馈控制，本文基于电阻应变片构建了反馈信号进行采集的系统，先用电阻应变片采集压电陶瓷得输出位移，然后通过标定系统将其转化为反射镜的偏转角度。并在此基础上，对系统的开环传递函数进行了辨识，得到了一个七阶的传递函数。实验证明，反馈信号采集系统能够兼顾体积和精度，所获得的传递函数能够较好地拟合该系统的动态特性，为后续控制算法的设计实现奠定了很好的基础。

Because precise feedback sensors are expensive and their transfer function is very complex, most FSM(fast steering mirrors) driven by PZT(PbZrTi03) use open-loop control technology. To implement closed-loop control for a new kind of three-dimensional FSM driven by three piezo ceramics, this thesis builds a feedback-signal acquisition system that uses a resistance strain gauge to obtain the linear displacement of the PZT, which is subsequently translated into angular displacement of the mirror through a calibrationsystem. As a basis for this acquisition system, the open-loop transfer function model of an FSM system was studied. The RLS(recursive least square) algorithm was used for parameter identification, and a transfer function model of the system was built successfully. Experimental results show that the feedback-signal acquisition system has high precision and the advantages of a small volume. The transfer function model fit the system acceptably.