Backstepping and dynamic control-allocation for attitude maneuver of spacecraft with redundant reaction fly-wheels

We develop a robust adaptive controller based on the backstepping method for the attitude maneuver of the spacecraft with unknown rotational inertia and unknown external disturbances. The stability of the closed-loop system is validated by using Lyapunov analysis. In considering the redundancy of the actuators-the reaction fly-wheels, we propose a dynamic allocation algorithm based on the constrained optimal quadratic programming for distributing the control command to the proper fly-wheel. This eliminates the physical restrictions on the fly-wheel characteristics and the limitation of the maximal torque, which are required in the conventional pseudo-inverse method. In addition, it also effectively suppresses the measurement noises and rejects the abnormal data from attitude sensors, improving the smoothness of the control torque. The proposed scheme has been applied to control the attitude maneuver of a wheel-control rigid spacecraft. Simulation results validate the efficacy of the proposed method.