A modified active disturbance rejection control for fast steering mirror in aerospace application

Abstract

Active disturbance rejection control (ADRC) has proved to be an effective tool in dealing with engineering problems related to the plant along with dynamic uncertainties, disturbances, nonlinearities. A modified active disturbance rejection control (MADRC) method is proposed to design the Fast Steering Mirror (FSM) controller. The modified extended state observer (ESO) incorporate with identified plant information is employed to reject the disturbances, nonlinear factors and modelling errors which meant to constraint the plant to a nominal form. Therewith, an well-designed analytical method is introduced to calculate the parameters of a feedback loop to force the plant response like a pre-designed model. Besides, a Lead-Leg Controller (LLC) consisting of two Tracking-Differentiator (TD) is designed to improve the performance of the controller. LLC generates a filtered output based on the expected plant dynamics to increase the FSM bandwidth, and LLC can also help to improve the stability of the system by restricting the tracking error in a limited range when there is an abrupt command input. The MADRC strategy is proven an effective solution for FSM. Simulation results show that the MADRC method can achieve a excellent performance without tedious tuning work. The experiment results proved the validation in practical application.