First Principles based High-precision Modelling and Identification of Piezoelectric Fast Steering Mirror

Abstract: We establish a high-precision composite model for a piezoelectric fast steering mirror (PFSM) using a Hammerstein structure. A novel asymmetric Bouc-Wen model is proposed to describe the nonlinear rate-independent hysteresis, while a dynamic model is derived to represent the linear rate-dependent component. By analyzing the physical process from the displacement of the piezoelectric actuator to the angle of the PFSM, cross-axis coupling is modeled based on first principles. Given the dynamic isolation of each module on different frequency scales, a step-by-step method for model parameter identification is carried out. Finally, experimental results demonstrate that the identified parameters can accurately represent the hysteresis, creep, and mechanical dynamic characteristics of the PFSM. Furthermore, by comparing the outputs of the identified model with the real PFSM under different excitation signals, the effectiveness of the proposed dual-input dual-output composite model is validated.