Distributed Supervisory Control of Discrete-Event Systems with Communication Delay
For researchers in discrete-event systems, this work extends existing distributed control theory to handle realistic communication delays, though the contribution is incremental.
This paper addresses the problem of communication delays in distributed supervisory control of discrete-event systems, proposing a method to test for delay-robustness. The approach identifies which communicated events are delay-critical and which are not, illustrated with a three-agent workcell model.
This paper identifies a property of delay-robustness in distributed supervisory control of discrete-event systems (DES) with communication delays. In previous work a distributed supervisory control problem has been investigated on the assumption that inter-agent communications take place with negligible delay. From an applications viewpoint it is desirable to relax this constraint and identify communicating distributed controllers which are delay-robust, namely logically equivalent to their delay-free counterparts. For this we introduce inter-agent channels modeled as 2-state automata, compute the overall system behavior, and present an effective computational test for delay-robustness. From the test it typically results that the given delay-free distributed control is delay-robust with respect to certain communicated events, but not for all, thus distinguishing events which are not delay-critical from those that are. The approach is illustrated by a workcell model with three communicating agents.