Fault-Tolerant Quantized Control for Flexible Air-Breathing Hypersonic Vehicles With Appointed-Time Tracking Performances

Abstract

This article contrives a fault-tolerant quantized control for flexible air-breathing hypersonic vehicles (FAHVs) with appointed-time tracking performances. At first, to online identify the lumped effect of actuator faults, flexible modes, parameter uncertainties as well as external disturbances, a hysteresis quantizer based neural estimator (HQNE) using finite precision state information is proposed, enabling a reduced communication load and computational time with a competitive estimation capability. Utilizing the estimation of HQNE, fault-tolerant quantized control laws equipped with auxiliary systems are established for FAHVs to realize a stable reference tracking result using discrete-time control signals, where auxiliary systems are employed to automatically monitor the impact of input saturation for command regulation. Furthermore, an appointed-time prescribed performance control based on a hyperbolic cosecant function is developed to make the tracking errors of velocity and altitude reach to the pregiven residual sets with a prescribed time in the absence of exact initial system states. The presented controller achieves a preassigned-time tracking performance for FAHVs under actuator faults and input saturation maintaining a decreased communication burden. The ultimately uniformly bounded stability of closed-loop system is proved through Lyapunov stability analysis, while numerical simulations are designed to verify the effectiveness of presented controller.