基于变迁覆盖的制造系统死锁控制策略

基于系统Petri网模型,研究柔性制造系统的死锁控制问题.论文利用变迁覆盖为系统设计活性控制器.变迁覆盖是由一组极大完备资源变迁回路组成的集合,其变迁集覆盖了Petri网中所有极大完备资源变迁回路的变迁集.验证变迁覆盖的有效性,然后仅对有效变迁覆盖中的极大完备资源变迁回路添加控制位置,就得到系统的活性受控Petri网.这种受控Petri网包含的控制位置个数少,从而结构相对简单.最后通过一个例子说明了所提出的死锁控制策略的构成与特点.

Transition cover-based deadlock control policies for manufacturing systems

Based on Petri net models of flexible manufacturing systems, the deadlock control problem is addressed. The concept of transition-cover is employed to design a live controller for flexible manufacturing systems. A transition cover is a subset of maximal perfect resource transition circuits whose transition set covers transitions of all maximal perfect resource transition circuits in Petri nets. After validating the effectiveness of a transition cover, we can build a live controlled Petri net by only adding a control place to each maximal perfect resource transition circuit in the effective transition cover. The number of control places in such a controlled Petri net is small and the structure of the controlled Petri net is simple. The proposed deadlock control policy is illustrated by an example.