Fault detection and compensation for linear systems over networks with Random delay and clock asynchronism

This paper proposes a fault detection and compensation scheme based on likelihood ratios for networked predictive control systems with random network induced time delay and clock asynchronism. The sets of predictive manipulated variables in a data packet are sent to the remote node at every sampling step, the compensator at the remote node receives the data packets and chooses the latest predictive manipulated variables as the input of plant to compensate the network time delay. The measured outputs are sent back to the local node with random delay and the observer updates based on the time schedule of remote node clock to avoid the deficiency of asynchronism. The likelihood ratios of fault are computed, and if a fault is detected and identified, the fault estimate is sent to the controller to compensate the fault. A numerical simulation is also given to validate the proposed method.