How lost messages can affect the dependability of a networked control system
Résumé
A networked control system (NCS) is a type of distributed control systems where sensors, actuators and other devices are interconnected by communication networks. When there is congestion in the communication network, some packets are dropped. In real time systems, particularly control systems, delays or dropped packets may be catastrophic and may cause instability in the control system. Due to the complexity of networked control system architectures, it is not trivial to evaluate there dependability level. The present paper aims at bringing a contribution relative to this aspect. We focused our interest on the effect of the lost messages on the dependability of a distributed control loop; the aim of this article is to present an approach to assess the impact of the messages lost on the dependability evaluation of networked control systems. Quantitative and qualitative studies are done to evaluate reliability and to find feared scenarios.