Robust nonlinear sequential loop closure control design for an air-breathing hypersonic vehicle model

This paper describes the design of a nonlinear robust/adaptive controller for an air-breathing hypersonic vehicle model. Due to its complexity, a high fidelity model of the vehicle dynamics derived from first principles is used only in simulations, while a simplified model is adopted for control design. This control-oriented model retains most of the features of the high fidelity model, including non-minimum phase characteristic of the flight-path angle dynamics and strong couplings between the engine and flight dynamics, whereas flexibility effects are regarded as a dynamic perturbation. A nonlinear sequential loop-closure approach is adopted to design a dynamic state-feedback controller that provides stable tracking of velocity and altitude reference trajectories and allows to impose a desired trim value for the angle of attack. Simulation results show that the proposed methodology achieves excellent tracking performances in spite of parameter uncertainties.