Precise Control for Gimbal System of Double Gimbal Control Moment Gyro Based on Cascade Extended State Observer

Coupling torque, nonlinear friction, and unmodeled dynamics are the main constraints that influence the angular speed precision of the gimbal systems in double gimbal control moment gyros (DGCMGs). This paper explores a novel angular speed tracking control method based on the cascade extended state observer (CESO). The coupling torque, nonlinear friction, and unmodeled dynamics are considered as the system's lumped disturbance, which is estimated by the designed CESO. By introducing a state feedback controller, the disturbances can be eliminated from the output channel of the system. Both simulation and experimental results confirmed the feasibility and effectiveness of the proposed method.