Robust Attitude Control and Disturbance Rejection for Flexible Spacecraft

This paper is concerned with the problem of attitude control and disturbance rejection of flexible spacecraft in the presence of parameter uncertainties. It is assumed that the external disturbance is generated by some nonlinear exosystems. The unit quaternion is used as the kinematic variables since it is free of singularity. A novel nonlinear internal model and robust Lyapunov based control law that require only the attitude and angular velocity measurement are proposed. The asymptotic stability of the overall closed-loop system is given via Lyapunov analysis. Finally, an illustrative example is provided to show the effectiveness of the proposed approach.