Variable structure tracking control of flexible spacecraft based on output feedback

To solve the attitude maneuver of a flexible satellite, this article presents a variable structure tracking control algorithm based on output feedback. For large angle maneuvers of a flexible spacecraft, on the foundation of establishing the dynamic equation of the flexible spacecraft relative to the reference trajectory, a variable structure tracking control algorithm is designed using only the measurements of attitude and angular velocity of the spacecraft. Accordingly the system tracking error (including the attitude tracking error and angular velocity tracking error) and the mode variables of the flexible appendage can be controlled from any initial state to a closed set with the origin inside; in addition, the attitude tracking error and angular velocity tracking error will finally converge to zero. Rigorous mathematical proof is given, and numerical simulation validates the feasibility and effectiveness of the control algorithm.