Object-Oriented Supervisory Control with a Class of Non- Deterministic Specifications

reusable software components, together with algorithms for automatic synthesis of the control software. In this paper will be shown how a certain type of nondeterministic specification for discrete event systems can be used with the supervisory control theory. A discrete event system will be regarded as a user-resource system, with a set of resources shared by a set of users. The users are seen as a specification on the behavior of the system. The sharing of the resources is modeled by interleaving the users, which results in a certain kind of nondeterministic specification. It is shown that the supervisory control theory still holds in this context, with a slight modification of the definition of supervisor completeness. 2. USER-RESOURCE SYSTEMS The systems arising from the modeling described in [3] contain a finite set of resources, autonomous reusable software models, each described as a Discrete Event Process (DEP). They are all considered deterministic, a not unrealistic assumption since we are modeling physical devices. Operating concurrently the resources constitute the plant. The resources are shared between a set of users, likewise described as DEPs but introduced and "detroduced" dynamically. These utilize the resources asynchronously and independently of each other. The control laws for such a user-resource system can be synthesized by means of the framework suggested by [6, 8], the SCT. We will assume some familiarity with the basic elements and the standard notations of the SCT.