Disturbance-observer-based sliding mode control for hypersonic flight vehicle

In accordance with characteristics of nonlinear and vulnerable to disturbance for hypersonic flight vehicle, a scheme of continuous sliding mode control based on extended state disturbance observer is proposed in this paper. A continuous sliding mode controller is designed on the basis of linear processing for nonlinear model of hypersonic flight vehicle. The controller is not only remaining the robust to uncertainties and unknown dynamics, but also eliminating the chattering phenomenon existing in traditional sliding mode control. An extended state disturbance observer is designed for external disturbance of the system. The external disturbance is estimated regarding as a system state variable, and the estimated value is used as a compensation amount in the sliding mode controller. Hence, the goal of counteracting the effect of disturbance is achieved. The simulation is conducted in the cruise flight condition of hypersonic flight vehicle. Simulation results show that the proposed approach meets the control requirements of hypersonic flight vehicle.