A Delay System Approach to Fault Detection Filter of Networked Control Systems

In this paper, the fault detection filter (FDF) design problem for networked control systems (NCSs) with both network-induced delay and data dropout is studied. Based on a new NCSs model proposed recently, an observer-based filter is introduced to be the residual generator and formulated as an H∞-optimization problem for systems with two successive delay components. By applying Lyapunov-Krasovskii approach, a new sufficient condition on stability and H∞ performance is derived for systems with two successive delay components in the state. A solution of the optimization problem is then presented in terms of linear matrix inequality (LMI) formulation, dependently of time delay. In order to detect the fault, the residual evaluation problem is also considered. An illustrative design example is employed to demonstrate the validity of the proposed approach.