Abstract: To realize rapid tracking of unpredictable angular input and effective rejection of dynamic disturbances for a four-axis gyro stabilized platform on moving base, an extended-state-observer (ESO) which takes angle position tracking error as observation input is introduced in the stabilization loop, The observer can simultaneously realize observation of the input angular acceleration and the torque disturbances. Directly implementing feedforward compensation with the observed results improves the stabilization accuracy greatly. To guarantee system stability with nonlinear saturation, a low-pass filter is introduced at the observer input end. Simulation and experiment results show that the proposed scheme can better realize inertial space stability of the platform under the coaction of unpredictable angular input and coupling torque disturbances, and the system is easy to realize, which provides reference for solving similar problems of electromechanical control system.

Key words: compensation, Coupling torque, Disturbance, Extended-state-observer, Feedforward control, Four-axis gyro-stabilized platform