Checking Delay Co-Observability of Discrete Event Systems with Two Local Supervisors

In this paper, for a given discrete event system and its specification language, we propose a method to check delay co-observability which is introduced to solve the decentralized nonblocking networked control problem under nondeterministic communication delays in our previous paper. We translate the checking problem of delay co-observability into tracking indistinguishable string collections under nondeterministic delays. A set of automata are constructed to capture these collections for different deterministic delays. Our results show that the specification language is delay co-observable if and only if there are no “bad” states in all the constructed automata. In this way, we successfully solve the verification problem of delay co-observability for the case with two local supervisors.