On a New Adaptive Disturbance Observer-Based Attitude Control Law for Hypersonic Vehicles

Aiming at the attitude control issue for hypersonic vehicles with the mismatched uncertainties, this paper presents an adaptive sliding mode disturbance observer-based backstepping control law. Firstly, the disturbance observer is designed based on the adaptive sliding mode technique, and the precise estimation of the disturbance is guaranteed via the Lyapunov stability theory. The merit of this disturbance observer is that the disturbance boundary is not known in advance. Then, the relationship for observer gains is given. At last, the backstepping control law for the hypersonic vehicle combining with the disturbance observer is developed. This control law is not only able to achieve the good tracking performance, but also robust against the mismatched uncertainties. The parameters perturbation and actuator restriction are considered in the numerical simulation, and the results demonstrate the effectiveness of the proposed approach.