Anti-Disturbance Control Based on Cascade ESO and Sliding Mode Control for Gimbal System of Double Gimbal CMG

Disturbance torque and unmodeled dynamics are the main important factors which affect the angular velocity precision of a gimbal system in double gimbal control moment gyro (DGCMG). In this paper, a compound control method combining reduced-order cascade extended state observer (RCESO) and integral sliding mode control (SMC) is proposed, aiming at effectively eliminating the influence of exogenous disturbances and unmodeled dynamics, and achieving high precision angular velocity control of the gimbal system. Firstly, the disturbance torque is observed by the RCESO, and the parameter tuning method of RCESO is studied. Secondly, to enhance the robustness of the whole control system and take into account disturbance estimation errors, an integral sliding mode control is introduced. Simulation and experimental results show that the proposed control method not only improves the compensation performance of the gimbal system with external disturbances, but also enhances the robustness and improves the angular velocity precision of the gimbal system.