Adaptive high order super-twisting control of hypersonic vehicle in climbing phase

Purpose Climbing tracking control of a hypersonic vehicle is a challenging problem because of the large model uncertainties and great variation of altitude and velocity. The purpose of this paper is to propose a novel adaptive high-order super-twisting control (AHOSTC) scheme to improve tracking control performance of hypersonic vehicles in the climbing phase. Design/methodology/approach First, the nonlinear longitudinal dynamics of the hypersonic vehicle model were established; meanwhile, the input–output feedback linearization method was applied to it for the convenience of the design of high-order sliding-mode control. Then, the novel AHOSTSC was proposed for a class of nonlinear systems subject to uncertainties, and the finite-time stability of the closed-loop system is analyzed. Then, by applying the proposed AHOSTSC to the input–output linearized hypersonic vehicle model, the velocity controller and altitude controller are directly designed. Finally, detailed comparison simulations are carried out. Findings Theoretical analysis shows that the closed-loop system is guaranteed finite-time stable in the presence of different uncertainties with unknown upper bounds. Simulation results show that, based on the proposed method, the velocity and altitude of the hypersonic vehicle converged to the desired value smoothly in finite time without obvious chattering phenomenon, and the robustness was also guaranteed. Originality/value The AHOSTC adaptively adjusts control gains in the case of a lack of knowledge about upper bounds of uncertainties. It increases the application scope of the conventional high-order super-twisting control method, which has important meanings for both sliding-mode control theory and flight controller design of hypersonic vehicles.