Adaptive Prescribed Performance Fault Tolerant Control for a Flexible Air-Breathing Hypersonic Vehicle With Uncertainty

This paper investigates a tracking control problem of a flexible air-breathing hypersonic vehicle (FAHV), where prescribed performance, actuator fault, and aerodynamic uncertainty are considered. Based on the backgrounds of FAHV and for designing controller simply, an uncertain control-oriented model is reasonably decomposed into velocity subsystem and altitude subsystem. Then, the dynamic inversion controller and robust adaptive back-stepping controller are, respectively, designed for each subsystem. At the level of control design, the upper bound of the lumped uncertainty is not to be known in advance, and the uncertainty is handled by the adaptive technique that is also utilized to deal with actuator fault. A novel first-order filter is designed to solve the “explosion of terms” problem inherent in back-stepping control. Third, the prescribed performance on tracking error that features the transient performance constraint on the tracking error is resolved by transforming the constrained problem into an unconstrained problem. Furthermore, the detailed stability analysis of the closed-loop system is carried out within the framework of Lyapunov theory, in which the tracking error converges to an arbitrarily small neighborhood around zero with the prescribed performance. Finally, compared simulation result illustrates the property of the designed control strategy in tackling prescribed performance, actuator fault, and aerodynamic uncertainty.