Fault detection of networked control systems in stochastic environments

This paper deals with the problem of fault detection for networked control systems in the stochastic environments. The packet dropout, networkinduced delay and out-of-order packets due to long delay are assumed to exist stochastically in the sensor-to-controller link and the controller-toactuator link. By assuming that the stochastic environment could be described as a homogeneous Markovian chain, the networked control system is modelled as a discrete-time, non-uniform sampling stochastic parameter-varying Markov jump system. Based on the model, the residual generator is developed and the problem of fault detection is formatted as a filtering problem. By using the theory of a Markovian jump linear system, a fault detection filter which makes the residual generation system stochastically stable is considered, and a prescribed disturbance attenuation level is satisfied. A sufficient condition to solve this problem is given in terms of the linear matrix inequalities. A numerical example shows that the proposed fault detection filter is sensitive to the fault but robust to exogenous disturbance.