Robust fault detection and isolation based on finite-frequency H-x002F Hx221E unknown input observers and zonotopic threshold analysis

This work proposes a robust fault detection and isolation scheme for discrete-time systems subject to actuator faults, in which a bank of H-x002F Hx221E fault detection unknown input observers x0028 UIOs x0029 and a zonotopic threshold analysis strategy are considered. In observer design, finite-frequency H- index based on the generalized Kalman-Yakubovich-Popov lemma and Hx221E technique are utilized to evaluate worst-case fault sensitivity and disturbance attenuation performance, respectively. The proposed H-x002F Hx221E fault detection observers are designed to be insensitive to the corresponding actuator fault only, but sensitive to others. Then, to overcome the weakness of predefining threshold for FDI decision-making, this work proposes a zonotopic threshold analysis method to evaluate the generated residuals. The FDI decision-making relies on the evaluation with a dynamical zonotopic threshold. Finally, numerical simulations are provided to show the feasibility of the proposed scheme.