Modeling and transfer function identification of FSM system

The fast steering mirror (FSM) was widely used in beam stabilization controlling systems. In order to ensure the FSM work more stably and precisely, the transfer function model of the FSM was deduced using giant magnetostrictive material as the displacement generator based on the material's physical properties and the dynamic characteristics of the FSM. With the actual measured result of the FSM's amplitude frequency response characteristics and phase frequency response characteristics, the accurate transfer function of the FSM was identified using the levy identification algorithm in the matlab software. Compared with the actual measured result, we concluded that the error of the transfer function obtained by identification is under 0.5 dB in magnitude and 5 in phase in the low and intermediate frequency range. The result shows that the transfer function model deduced is reasonable and supplied theoretic reference of how to improve FSM's performance in its application system.