FEEDBACK-CONTROL SYNTHESIS FOR A GLASS OF CONTROLLED PETRI NETS WITH TIME CONSTRAINTS

In this paper a cyclic place-timed controlled marked graph (PTCMG), wh ich is an extended class of a cyclic controlled marked graph (CMG), is presented as a model of discrete event systems (DESs). In a PTCMG, ti me constraints are attached to places instead of transitions. The time required for a marked place to be marked again is represented in term s of time constraints attached to places. The times required for an un marked place to be marked under various controls, are calculated. The necessary and sufficient condition for a current marking to be in the admissible marking set with respect to the given forbidden condition i s provided, as is the necessary and sufficient condition for a current marking to be out of the admissible marking set with respect to the f orbidden condition in one transition. A maximally permissive state fee dback control is synthesized in a PTCMG to guarantee a larger admissib le marking set than a CMG for most forbidden state problems. Practical applications are illustrated for a railroad crossing problem and an a utomated guided vehicle (AGV) coordination problem in a flexible manuf acturing facility.