Sliding mode backstepping control for hypersonic aircraft based on nonlinear disturbance observer

Aiming at the feature that hypersonic aircraft's nonlinear dynamics system is highly nonlinear,multivariable coupled and includes uncertain parameters,a new backstepping sliding mode controller is designed based on nonlinear disturbance observer(NDO) and backstepping sliding mode control scheme.The NDO is used to observe the disturbance of the system.Sliding mode control is adopted in every backstepping design to compensate unknown disturbance.The approach prevents cumulative errors and realizes robust output tracking for guidance orders.The system is proved to be stable.Simulation results show this method can observe the disturbance ideally and enhance the robust performance of the system.