Discrete-event dynamic systems

The supervisory control theory of discrete-event dynamic systems (DEDS), first introduced by Ramadge and Wonham, is based on an automata concept. Given a process, the objective of this theory is to design a supervisor in such a way that the process coupled with the supervisor behaves according to various constraints. In this framework, the process is assumed to evolve spontaneously and the supervisor can only prevent some events from occurring, but cannot force them. In fact, most processes require the addition of an external control agent that forces some events to occur. This has led us to the supervised control concept where control and supervision are separated. This provides a hierarchical frame, thus enabling us to formalize and to systematize the transition from the synthesis to the implementation of the control. In the paper, Grafcet is intensively used for the supervision and the control design