Supervisor localization of timed discrete-event systems under partial observation

Abstract

We study supervisor localization for timed discrete-event systems under partial observation in the Brandin-Wonham framework. First, we employ timed relative observability to synthesize a partial-observation monolithic supervisor; the control actions of this supervisor include not only disabling action of prohibitible events (as that of controllable events in the untimed case) but also “clock-preempting” action of forcible events. Accordingly we decompose the supervisor into a set of partial-observation local controllers one for each prohibitible event, as well as a set of partial-observation local preemptors one for each forcible event. We prove that these local controllers and preemptors collectively achieve the same controlled behavior as the partial-observation monolithic supervisor does. In the resulting local controllers/preemptors, only observable events can cause state change. The results are illustrated by a timed workcell example.