Reliability modeling of networked control systems using dynamic flowgraph methodology

The recent trend in deploying communication networks in digital control systems to form Networked Control Systems (NCSs) brings the need for utilizing dynamic methods to assess the reliability of these systems. The methods should be able to capture the behaviour and interaction of the hardware, the software and the communication network in the NCSs. They should also be able to incorporate time dependency and multi-state behaviour. In this paper, it is demonstrated how the Dynamic Flowgraph Methodology (DFM) can be a promising method to fulfill these requirements. The behaviour and the effect of the communication network on NCS performance is emphasized. The information provided by analysis of the implemented model facilitates the improvement of the control system performance.