Piezoelectric-based large-angle stroke fast steering mirror with high ratio of output range to resolution and self-sensing capability.

In space optical applications, the piezoelectric-actuated fast steering mirror (FSM) is one of the pivotal components for high-precision beam capturing and trajectory tracking. The FSM is restrained in small-angle scanning applications due to the short actuation stroke of the incorporated piezoelectric materials. This study introduces a dual-axis sub-radian stroke FSM with a high ratio of output range to resolution and self-sensing capability, based on cascading structures for displacement amplification and flexible parts for feedback. Theoretical analyses and finite element analysis (FEA) are applied to elucidate the driving and deformation mechanisms of the proposed FSM structure. To ensure the performance of the proposed FSM, the double-loop control strategies are implemented independently for rotation around the two orthogonal axes. Experimental results reveal that both axes can rotate 148.67 mrad under the closed-loop control, with the ratio of output range to resolution larger than 3.90 × 104, superior to existing FSMs. We further demonstrate with designed experiments of tracking complex trajectories that the relative tracking accuracy error remains lower than 0.02%.