Feedback logic for discrete event systems with arbitrary control patterns

Abstract

We consider controlled discrete event systems as formulated by Golaszewski and Ramadge, with a control specification assumed to be given in terms of predicates. First, we discuss the unique existence of the maximally and minimally permissive (practical) feedbacks. Next, we consider a specification in a modular fashion, and study the relationship between the control-in variance of the total predicate and that of component predicates. Finally, it is shown that, under a certain condition, if each component predicate has unique maximally and minimally permissive feedbacks, the unique maximally and minimally permissive practical feedbacks for the conjunction of component predicates exists in the intersection of the sets of permissive feedback for them. Moreover, we demonstrate modular feedback synthesis for a simple manufacturing system