Fault-Tolerant Track Control of Hypersonic Vehicle Based on Fast Terminal Sliding Mode

In this paper, the track control problem of hypersonic a vehicle with modeling uncertainties, external disturbance, and multifault is studied and analyzed. First, a fault model of a second-order system including disturbance is established by introducing auxiliary error variables on the basis of feedback linearization for a longitudinal model of the hypersonic vehicle. Second, for a fault-free actuator and system model with unknown upper bound disturbance, a fast adaptive terminal sliding mode controller is designed, which ensures the sliding mode manifold is finite-time stable. To solve the multifault problem of actuator, based on the passive fault-tolerant control method, a fast adaptive terminal sliding mode fault-tolerant controller is designed, which guarantees that the system state is finite-time stabile in the event of actuator failure. The controller adopts two adaptive algorithms to estimate the unknown fault information and system disturbance information. Finally, a rigorous proof using Lyapunov theory is given for the stability of the designed controllers. Numerical simulation is run for the longitudinal nonlinear dynamic model of a hypersonic vehicle and simulation results prove the effectiveness of the two designed controllers.