Observer-based fault detection for stochastic delayed systems in network environment

In this paper, the problem of fault detection (FD) for nonlinear networked control systems (NCSs) with network-induced stochastic interval delay is investigated. By employing the information of probabilistic distribution of networked-induced time-varying delay and considering the observer-based fault detection filter as residual generator, nonlinear stochastic delayed system model is established. Based on the obtained nonlinear stochastic filter error system model, fault detection of nonlinear NCSs is formulated as nonlinear H_∞ problem. Especially, the stochastic stability and prescribed H_∞ attenuation level are achieved by choosing appropriate Lyapunov functional, the desired fault detection filter is constructed in terms of certain linear matrix inequalities (LMIs), which depends on not only delay-interval but also on delay-interval-occurrence -rate. Numerical examples are provided to illustrate the effectiveness and applicability of proposed technique.