Fast Mirror Sliding Mode Control based on Dilated State Observer

Fast steering mirrors are widely used in various high-precision optical systems, such as adaptive optics, laser communication, beam stabilization systems, and advanced manufacturing. Fast mirrors need to have fast dynamic response ability and good anti-interference performance. This study examines the dynamic behavior of a fast mirror system and develops a mathematical model to account for uncertainties arising from internal movements and external interferences. Building upon this basis, an improved sliding mode control approach incorporating an extended state observer is proposed. This observer dynamically estimates unforeseen disturbances in real time and directly offsets their effects within the controller, effectively reducing chattering and enhancing practical implementation while ensuring the tracking error remains within the required accuracy range. Simulation results show that, compared to a traditional sliding mode controller, the proposed method reduces the rise time by 50.4% and lowers the settling time by 39.1%, and enhances tracking accuracy by 30.5%. These enhancements meet the operational demands of the fast mirror system and significantly improve its dynamic performance.