New results on decentralized supervisory control of discrete-event systems

We present results on decentralized supervisory control of discrete-event systems. We generalize the control architecture by allowing combinations of “fusion by intersection” and “fusion by union” for the control actions issued by the individual (local) supervisors. The algebraic properties of co-observability in the context of this general architecture are presented. We show that appropriate combinations of fusion rules with corresponding decoupled local decision rules guarantee the safety of the closed-loop behavior with respect to a given specification that is not co-observable. We characterize an “optimal” combination of fusion rules among those combinations guaranteeing the safety of the closed-loop behavior. In addition, a simple supervisor synthesis technique generating the infimal prefix-closed controllable and co-observable superlanguage is presented