Closed-loop fault detection for full-envelope flight vehicle with measurement delays

A closed-loop fault detection problem is investigated for the full-envelope flight vehicle with measurement delays, where the flight dynamics are modeled as a switched system with delayed feedback signals. The mode-dependent observer-based fault detection filters and state estimation feedback controllers are derived by considering the delays' impact on the control system and fault detection system simultaneously. Then, considering updating lags of the controllers/filters' switching signals which are introduced by the delayed measurement of altitude and Mach number, an asynchronous ^H∞ analysis method is proposed and the system model is further augmented to be an asynchronously switched time-delay system. Also, the global stability and desired performance of the augmented system are guaranteed by combining the switched delay-dependent Lyapunov-Krasovskii functional method with the average dwell time method (ADT), and the delay-dependent existing conditions for the controllers and fault detection filters are obtained in the form of the linear matrix inequalities (LMIs). Finally, numerical example based on the hypersonic vehicles and highly maneuverable technology (HiMAT) vehicle is given to demonstrate the merits of the proposed method.