Recursive terminal sliding mode control for hypersonic flight vehicle with sliding mode disturbance observer

Abstract

A recursive terminal sliding mode controller (RTSMC) based on sliding mode disturbance observer (SMDOB) is proposed for the longitudinal dynamics of a generic hypersonic flight vehicles (HFVs) in the presence of parametric uncertainties, measurement noises and external disturbances. First, a sliding mode tracking controller is presented by introducing recursive terminal sliding mode manifolds, in which each manifold will reach zero subsequently in finite time as well as the usual singularity problem will not occur. The RTSMC embraces advantages of both nonsingular terminal sliding mode control and high-order sliding mode control. Next, for the sake of enhancing the robustness of controller for uncertainties, a SMDOB is proposed to estimate and compensate the disturbances. Then, a composite controller that is composed of RTSMC and SMDOB is designed, and its stability is analyzed utilizing Lyapunov function method. Finally, numerical simulation is conducted for cruise flight condition of HFV. Simulation results show the expected control performance.