Dynamic sliding mode control of a hypersonic flight vehicle

A kind of sliding mode flight controller based on dynamic sliding mode principle is proposed for the longitudinal dynamics of a hypersonic flight vehicle. For its input/output linearized model, an auxiliary sliding mode variable is constructed. The dynamic sliding mode control law is introduced and the dual-phase convergent process is implemented. The auxiliary sliding mode and conventional sliding mode are both proved to be convergent in finite time and the condition of controller parameters to be satisfied is given. Using this method, the discontinuous control output is integrated, and the chattering is effectively reduced. Simulation studies are conducted for a stable cruise condition at the height of 33 528 m and the speed of Mach 15. The simulation results demonstrate that the proposed dynamic sliding mode controller reduces the sliding chattering, and has better robustness when there are parameter uncertainties.