Adaptive accommodation of failures in second-order flight control actuators with measurable rates

In this paper effective failure detection, identification and reconfiguration (FDIR) algorithms are developed for a class of linearized aircraft models and second-order actuator dynamics. Assuming that the actuator dynamics are fast, a baseline controller is designed and, using the singular perturbation arguments, shown to achieve the control objective. Typical failures in flight control actuators described by first and second order dynamics are considered next, and the FDI algorithms are derived for the latter case. This is followed by the design of a corresponding adaptive reconfigurable controller, and the main theorem is proved stating that all the signals in the system are bounded and that the tracking error converges to zero asymptotically despite multiple simultaneous actuator failures. The properties of the proposed FDIR algorithms are evaluated through numerical simulations of the F-18 aircraft.