Hybrid control and steering logic for the CMG-based spacecraft attitude control system
Considering the momentum singularity characteristics, an integrated control strategy for the control moment gyros based attitude control systems is proposed, in which the angular momentum conservation between the spacecraft and the CMG is utilized to improved the system performance both in the closed loop responsiveness and the singularity controllability. The moment exchange capability of the CMGs can be fully developed by the control logic under normal operation, while the exchange space is specifically restrained to guarantee the effectiveness of the singularity avoidance steering when gimbal lock occurs. An online uncertainty identification method based on the momentum exchange property is applied in the hybrid control logic to improve the robustness of the system for the first place, and the remaining uncertainty is further handled by an adaptive control law. Numerical simulations for the practical agile spacecraft maneuvering are conducted to verify the effectiveness of the proposed algorithms.