Sliding mode controller design for rigid satellite attitude tracking

The problem of attitude tracking control for rigid satellite is studied in this paper. Based on the dynamic equation and kinematics equation using error quaternion and error angular velocity, a sliding mode controller is initially designed to solve this problem. In order to avoid inherent chattering of sliding mode control and then improve control effect, a disturbance observer is introduced and included in the modified controller. The convergence of both controllers are respectively proved theoretically. Simulations are finally performed and the results demonstrate the performance of proposed controllers.