Two-axis flexure support structure design of fast steering mirror

The fast steering mirror system (FSM) is a high-performance optical device, and the mechanical characteristics of its supporting structure directly affect the system's response speed and closed-loop bandwidth. The paper designs a two-axis flexure support structure based on an elliptical-hyperbolic hybrid flexure hinge, some working requirements of the flexible support structure are clarified. The mathematical model of the two-axis rotational stiffness of a flexure support structure is developed. In response to the resonance frequency requirements of the FSM system, the primary structural parameters of the flexure hinges are selected. Finally, the modal analysis of the system is conducted using finite element software. The analysis results demonstrate that the simulated resonance frequencies of the FSM system in two working directions have a relative error of less than 5% compared to the theoretical calculation results, validating the rationality of the chosen parameters for the flexure hinge structure.