Decentralized Control of Timed Discrete Event Systems with Conditional Decisions for Enforcement of Forcible Events

In this paper, we introduce conditional decisions for enforcing forcible events in the decentralized supervisory control framework for timed discrete event systems. We present necessary and sufficient conditions for the existence of a decentralized supervisor with conditional decisions under the assumption that if the occurrence of the event tick, which represents the passage of one time unit, is illegal, then a legal forcible event that should be forced to occur uniquely exists. These necessary and sufficient conditions are weaker than those for the existence of a decentralized supervisor without conditional decisions. In addition, we present how to verify the presented necessary and sufficient conditions.