Attitude Tracking Control for Hypersonic Flight Vehicles Based on Sliding Mode Observers

In this paper, a novel backstepping control scheme based on sliding mode observers is proposed for the attitude system of a hypersonic flight vehicle. By employing sliding mode observers, the estimations of the disturbances and extra dynamics are guaranteed to converge to their exact values in finite time. The control scheme is designed through backstepping approach, which benefits for compensating the mismatched disturbances. Then the Lyapunov stability analysis is given to prove that the closed-loop system which contains the observers, the controller and the vehicle is asymptotically stable with attitude states converging to reference signals. Simulation results are provided to demonstrate the effectiveness of the proposed control method.