Sliding mode predictive control for hypersonic vehicle

Considering the nonlinearity, strong coupling, fast time-varying and uncertainty of hypersonic vehicle, a sliding mode predictive control strategy is proposed, in which the strong robustness of sliding mode control is combined with the ability of predictive control for handling the constraints. The longitudinal dynamics of hypersonic vehicle is linearized at the equilibrium to get the predictive model. Then pole placement is adopted to design asymptotically stable sliding mode surface following the small perturbation linearized model, and the sliding mode surface is predicted and optimized in the performance index. The optimization problem becomes a quadratic programming problem by matrix transformation, thus the frequent switching on the sliding mode surface is avoided and the chattering is suppressed. Simulations show that the altitude and velocity are tracked accurately even with parameter uncertainties, and the control and state are all in the limited scope. The steady-state tracking errors approach the sliding mode surface, and keep staying on the sliding mode surface without chattering.