Delay compensation in packet-switching networked controlled systems

In this paper, we consider the problem of stabilizing sufficiently smooth nonlinear time-invariant plants over a network whereby feedback is closed through a limited-bandwidth digital channel. Reliable packet switching networks are explicitly considered, for which both the time between consecutive accesses to each node (MATI) and the delay by which each data packet is received, processed, and fed back to the plant are unknown but bounded. For what concerns networked feedback control, the main difference between a packet-switching and a circuit-switching network with the same bandwidth is that packets can convey larger amounts of feedback data (measurements and control inputs) with much higher latency and jitter than a conventional communication channel. To compensate the unpredictably varying delays in packet switching networked control systems, we propose a model-based strategy that exploits the relatively high payload which can be associated to each packet. A bound on the tolerable delays and access frequency is explicitly provided.