Fault detection for networked systems with random delays and packet losses

• Fault detection (FD) in network with random delays and packet losses is studied.
• A new model is developed for one-step random delay, packet losses and channel noise.
• A linear optimal filter in the linear minimum variance sense is presented.
• An improved weighted sum of squared residuals (IWSSR) detection method is presented.
• A norm-bounded (NB) fault detection method is also proposed.

This paper is concerned with the fault detection (FD) in networked systems (NSs). A new model is established by using two Bernoulli stochastic variables to describe the phenomena of one-step random delays and packet losses in data transmission. A new linear filter is designed in the linear minimum variance sense using the innovation analysis approach. Based on the proposed filter, an improved weighted sum of squared residuals (IWSSR) fault detection method is presented. When the packet loss rate is low, it has an effective performance, but it may lose the effectiveness if the packet loss rate is high because the innovation has lost the normal distributed property. To solve this problem, a norm-bounded (NB) fault detection method is also proposed, which avoids the restriction that requires innovation satisfying the normal distribution. In the simulation, the performances of the proposed IWSSR and the NB fault detection methods are verified.