Adaptive high order sliding mode controller design for hypersonic vehicle

A nonlinear robust control strategy for hypersonic vehicle in tracking the responses to a step change in altitude and airspeed is proposed. The vehicle model is nonlinear, multivariable, unstable, and includes uncertain parameters. Firstly, the analysis is conducted for the hypersonic vehicle model via input-output (I/O) linearized technique. Secondly, the sliding mode manifold is designed based on the homogeneity theory. Then, the adaptive high order sliding mode controller is proposed to achieve the tracking for hypersonic vehicle with bounded uncertainty but its boundary is not known in advance. Furthermore, the stability of the system is proved via Lyapunov theory. Finally, the simulation results are provided to demonstrate the effectiveness of the proposed control strategy.