On Supervisory Control of Real-Time Discrete-Event Systems

A discrete-event system G is modelled as the controlled generator of a formal language L(G), in the framework of Ramadge and Wonham. By means of the concepts of well-posed language and well-posed supervisor, it is suggested how this framework can accommodate certain real-time control constraints. Then it is shown that a closed-loop supervisory control has `correct' real-time behavior if and only if the supervisor is well-posed (with respect to time delay).