Adaptive immersion and invariance sliding mode control for hypersonic vehicles with parametric uncertainty

In this paper, a multi-input/multi-output (MIMO) adaptive sliding mode control system based on immersion and invariance (I&I) methodology is developed and analyzed for the longitudinal dynamics of a flexible air-breathing hypersonic vehicle whose model is multivariable, nonlinear, and includes parameter uncertainty. Sliding mode controllers combined with on-line parameter estimators based on adaptive I&I theory are synthesized to suppress the significant aerodynamic parameter uncertainties. The stability of the closed-loop control system is proved by the Lyapunov stability theory. Simulation experiments are conducted to evaluate the robustness of the controller system with respect to parametric uncertainty, which meanwhile show the effectiveness and high performance of the controller system in terms of aggressive maneuvering control inputs.