Fault Detection Observer Design in Low Frequency Domain for Linear Time-delay Systems

This paper deals with the robust fault detection (FD) problem in low frequency domain for linear time-delay systems. The H∞ norm and H− index are used to measure the robustness to unknown inputs and the sensitivity to faults, respectively. The main results include derivation of a sufficient condition for the existence of a robust FD observer and its construction based on the linear matrix inequality (LMI) solution parameters. Finally, numerical simulations show the effectiveness of the presented methodology.