Fast Composite Control of Piezoelectric Actuated Fast Steering Mirrors

To further improve the control performance of laser communication precision tracking system, this paper studies the control method of piezoelectric ceramic driven fast steering mirror (FSM). A composite control strategy combining a novel nonlinear extended state observer and a nonsingular fast terminal sliding mode is proposed to address the nonlinear characteristics such as hysteresis and creep of piezoelectric ceramic materials and external disturbances. Firstly, a novel nonlinear extended state observer is designed for the transfer function of second-order systems to estimate angular velocity and external disturbances. Secondly, establish a nonsingular fast terminal sliding surface and use hyperbolic tangent function instead of sign function to suppress sliding mode chattering phenomenon. Finally, the effectiveness of the proposed control method is verified through comparative experiments. The experimental results show that the proposed control method has faster convergence, excellent robustness, and more accurate tracking performance, indicating that the proposed control strategy is effective and meets the requirements of laser communication FSM for high accuracy and strong anti-interference.