Inhibitor arc based state avoidance controller for non-convex forbidden state problems in Petri nets

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 OR-logics, which is impossible in ordinary PN structure-type controllers. The significance of IA-controller is that the controller can be easily implemented in the plant model. In addition, IA-controllers are synthesized in a modular way in order to solve multiple forbidden conditions