Control of Petri nets with partial place information

In this paper, controlled Petri nets with partial place information is investigated. Petri nets can represent concurrency, and have stronger description capacity. The extended automata model (EAM) which includes concurrent event transitions is highlighted since it is an adequate model for theoretical analysis. Beside that, the authors use predicate logic for compact representation. The basic problem of interest is to chose an appropriate control rule based on the partial place information of the system to ensure that a given predicate on the marking set of the process remains invariantly true whenever it is initially satisfied. The concept of an observable predicate considering concurrency is introduced. It is shown that a predicate can be controlled to remain invariant if and only if the predicate is both controllable and observable. The authors introduce a stronger version of observability, called normality. Based on this, some explicit solution formulae applicable to synthesis problems are given. They also discuss the maximally concurrent control problem.<>