柔性制造系统是一类重要的离散事件动态系统,它的运行特性分析及系统优化已引起了广泛的注意。本文研究 Cohen 模型描述的一类柔性制造系统的运行特性,着重分析系统的加工时间矩阵与系统运行效率的关系。应用本文的结论,可以找到一大类具有相同运行效率的柔性制造系统,这对于系统的优化是有意义的,文中的例子不仅证实了各种结论,而且对于生产线上的排序问题有启发意义。 Flexible manufacturing system is an important type of discrete event dynamic system. Its operation characteristics analysis and system optimization have attracted a lot of attention. This paper studies the operating characteristics of a type of flexible manufacturing system described by Cohen model, and emphatically analyzes the relationship between system processing time matrix and system operating efficiency. Using the conclusion of this article, we can find a large class of flexible manufacturing systems with the same operating efficiency, which is meaningful for the optimization of the system. The examples in this paper not only confirm various conclusions but also inspire scheduling problems on the production line.