Tube-Based Composite Fault-Tolerant Control Method for Flexible Hypersonic Vehicle

In this paper, a composite fault-tolerant control (FTC) method based on tube model predictive control (Tube-MPC) is proposed for the flexible hypersonic vehicle with actuator fault. The polytopic linear parameter varying (LPV) model with loss of effectiveness fault of elevator and parameter uncertainty is established. The actuator saturation is converted into the state-dependent virtual input constraints. To detect fault occurrence, a fault diagnosis method based on Luenberger observer is introduced. The \(L_1/H_{\infty }\) $L_1/H_{\infty }$ performance indexes are used to increase the observer residual’s disturbance robustness and fault detection sensitivity. The time-varying threshold is developed using the observer residual and Lyapunov function. In addition, an extended state observer (ESO) is developed to estimate the lumped term composed of fault and additional disturbance. Correspondingly the composite FTC controller is developed, where the fault compensation law and the baseline Tube-MPC laws via sum of squares (SOS) for different bounds of disturbances are designed, respectively. Finally, the simulation results verify that the proposed composite FTC controller is effective for the flexible hypersonic vehicle.