为解决一类具有多资源服务处理制造系统中的死锁问题,提出了利用Petri网描述系统结构和动态特征的方法,以及循环结构的新概念,证明了循环结构是导致系统死锁的惟一结构特征。利用辅助系统Petri网模型,提出了计算系统的所有基本极大循环结构的方法。对每个基本极大循环结构增加一个控制位置及其相关弧以限制其资源的利用,从而有效地避免系统死锁的发生。
To solve deadlock problems in a kind of automatic manufacturing system with multiple resource service, a method to describe system structures and dynamic characteristics by Petri nets was proposed. And the concept of cyclic structure in the system Petri net models was defined. The cyclic structures were proved to be the unique subnet structures of the system Petri net model, which could lead to system deadlock. By introducing the auxiliary system Petri net model, a method to compute all elementary maximal cyclic structures was presented, By adding a control place and its related arcs to each elementary maximal cyclic structure to restrict its resource usage, the deadlock could be successfully avoided.