Abstract: An adaptive discretetime variable structure control algorithm is proposed for large angle attitude maneuver of rigid spacecraft in the presence of parametric uncertainty and external disturbances. The affine system including attitude kinematics and dynamics equations is modeled and decoupled by inputoutput feedback linearization. Then the linear dynamic equations are discretized and the discretetime variable structure control law is obtained via the exponential approach law. Finally, the parametric adaptation law is designed based on Lyapunov stability theory to overcome multiple timevarying and disturbance terms in models. The simulation results indicate that the proposed algorithm can decrease the attitude tracking deviations caused by the parametric perturbations and external disturbances effectively. In addition, the system ensures the accuracy and robustness of the large angle attitude maneuver and eliminates the conventional control chattering.

Key words: rigid spacecraft, large angle maneuver, attitude decoupling control, discretetime variable structure control