Development of a novel two-DOF piezo-driven fast steering mirror with high stiffness and good decoupling characteristic

摘要

A novel two-DOF piezo-driven fast steering mirror (PFSM) with high stiffness and good decoupling characteristic was proposed. This PFSM could realize rotary motions around X-axis and Y-axis by differential push-pull structure with four piezoelectric stack actuators (PSAs) arranged in cross and orthogonal state, and its lateral stiffness was high enough to overcome the problem that PSA was easy to be destroyed by large lateral force. The PFSM was designed and its working principle was described in detail. The static model was established to analyze the stiffness characteristic of the structure and precisely predict the output angles. The finite element method (FEM) was performed to verify the effectiveness of the proposed structure and static model. A prototype of the PFSM was fabricated, and an experimental setup was established. The experiments showed that the proposed PFSM could achieve rotary motion ranges of 2.33 mrad around X-axis and 2.25 mrad around Y-axis under the voltage of 120 V, respectively. And the resolution was measured as high as 0.28 μrad with the voltage increment of 0.2 V. Furthermore, the first order resonance frequency was measured as 4578 Hz and a good decoupling characteristic was obtained, the coupling errors of both two axes were below 0.75%. The two-DOF PFSM could be applied to the laser communication and the adaptive optics system based on its merits of high stiffness, high resolution and good decoupling characteristic.