Decentralised fault detection of large-scale systems with limited network communications

An optimal decentralised fault detection (FD) system is proposed for a class of discrete-time large-scale systems, where limited information exchange among subsystems is enabled with communication networks. Such an FD system consists of two parts in each subsystem: a residual generator (RG) and a residual evaluator. By taking the advantages of network communications, the RGs are designed to match a proper reference model in a stochastic sense such that a best trade-off between the robustness against disturbances and the sensitivity to faults can be achieved. In each residual evaluator, a norm-based evaluation function is selected for evaluating residual signals and a corresponding threshold is calculated for detecting the occurrences of faults. All the solutions are presented in the form of linear matrix inequalities. Finally, a numerical example is given to illustrate the results and the improvement achieved by applying network communications.