关键词: 柔性制造系统, 死锁预防, Petri网, 基本信标

Abstract: To solve the problem of deadlock prevention for a class of Petri nets, S3PMR, an optimal deadlock prevention policy was proposed. Once the optimality couldnt be guaranteed, the position of the output arcs was optimized by structural analysis of the supervisor. Strict minimal siphons of an S3PMR were divided into elementary and subordinate ones. For each elementary siphon, a monitor was added to ensure invariantcontrolled without generating emptiable controlinduced siphons. The controllability of a subordinate siphon was ensured by changing the control depth variables of its related elementary siphons, which led to a livenessenforcing Petri net supervisor for a plant model. Furthermore, the methodology of this research would lead to a structurally simple livenessenforcing supervisor with more permissive behaviors.

Key words: flexible manufacturing systems, deadlock prevention, Petri net, elementary siphon