IEEE Transactions on Automatic Control, Vol.65, No.3, 925-940, 2020
The Value of Timing Information in Event-Triggered Control
We study event-triggered control for stabilization of unstable linear plants over rate-limited communication channels subject to unknown bounded delay. On one hand, the timing of event triggering carries implicit information about the state of the plant. On the other hand, the delay in the communication channel causes information loss, as it makes the state information available at the controller out of date. Combining these two effects, we show a phase transition behavior in the transmission rate required for stabilization using a given event-triggering strategy. For small values of the delay, the timing information carried by the triggering events is substantial, and the system can be stabilized with any positive rate. When the delay exceeds a critical threshold, the timing information alone is not enough to achieve stabilization, and the required rate grows. When the delay equals the inverse of the entropy rate of the plant, the implicit information carried by the triggering events perfectly compensates the loss of information due to the communication delay, and we recover the rate requirement prescribed by the data-rate theorem . We also provide an explicit construction yielding a sufficient rate for stabilization, as well as results for vector systems. Our results do not rely on any a priori probabilistic model for the delay or the initial conditions.
Keywords:Delays;Communication channels;Payloads;Information processing;Entropy;Upper bound;Control under communication constraints;data-rate theorem;event-triggered control;quantized control