信标基底的可选择性在制造系统死锁控制中的应用

Application of selection of siphon basis to deadlock control of manufacturing systems

中文关键词  柔性制造系统  Petri网  死锁控制  信标基底

英文关键词  flexible manufacturing systems  Petri nets  deadlock control  siphon basis

中文摘要

      本文基于Petri网模型, 讨论柔性制造系统的死锁控制问题. 为了建立结构简单的Petri网控制器, 本文在以前的 工作中提出了信标基底的概念. 信标基底是一组满足特定条件的严格极小信标集合. 本文证明基于不同的信标基底, 建 立的受控系统其容许性能也不同. 而容许性是评价死锁控制策略优劣的重要标准之一. 故如何选择信标基底, 提高受控 系统的容许性能是值得研究的问题. 本文讨论了使受控系统容许性能大大提高的信标基底的选择条件. 基于该条件, 为 柔性制造系统建立有效的死锁控制策略. 最后, 通过两个例子解释该条件和策略.

英文摘要

      Deadlock control problem of flexible manufacturing systems is addressed based on Petri net models. The concept of siphon basis has been proposed to obtain a Petri net controller with small size in our previous work. Siphon basis is a set of strict minimal siphons satisfying some specific conditions. However, it is verified that the performances of controlled Petri nets based on different siphon basis are different in this paper. As is well known, behavior permissiveness is one of the most important criteria in evaluating the performance of controlled Petri nets. It is significant to address how to select siphon basis to improve the performance of controlled Petri nets. The condition under which the performance of Petri net controllers can be largely improved is explored. Based on the condition, an efficient deadlock control policy for flexible manufacturing systems is established. Finally, two examples are provided to demonstrate the proposed condition and policy.