Decision making improvement for diagnosis in Networked Control Systems based on dynamic message scheduling

The fault detection problem is studied in this paper for a class of linear Networked Control Systems (NCS) with communication delays (which increase with the load of the network). The residual function, which is used for fault detection, is not identically zero in the fault free case. Among the factors which influence the residual function we focus on the communication delays. In order to reduce the impact of the delays which depend on the load of the network we propose to use an hybrid priority scheme, including dynamic and static part, for message scheduling (the network CAN is considered). The dynamic part is based on the dynamic performance of the controlled application. Such message scheduling mechanism improves the fault diagnosis in the sense that it avoids the false alarms and what we call a rebounding diagnosis.