Inhibitor arc based state avoidance controller for non-convex forbidden state problems in Petri nets
Young Cheol Cho, Wook Hyun Кwon · 2002
In this paper, a state avoidance controller with inhibitor arcs called "IA-controller" is proposed for nonconvex forbidden state problems in Petri nets. The forbidden condition is transformed into non-convex marking constraints in controlled PNs. Simple formulas for IA-controllers are developed to avoid the non-convex marking condition. By extending enabling rule of controllable transitions, the IA-controller can realize ORlogics, which is impossible in ordinary PN structuretype controllers. The significance of IA-controller is that the controller can be easily implemented in the plantmodel. In addition, IA-controllers are synthesized in a modular way in order to solvemultiple forbidden conditions. keywords : Petri nets, forbidden state problem, nonconvex constraint. 1 Introduction In recentyears, muchresearch has focused on the synthesis of controllers in discrete event systems (DESs). To achieve their desired behaviors, it is essential to guarantee that the system never enter forb...