从离散事件系统模型看扰动对FMS的影响

The Effect of Disturbance on FMS——A Study of Discrete Event Systems

以柔性制造系统为背景,分析一类离散事件系统模型参数矩阵及输出如何受扰动的影响.通过扰动分析,展示了扰动被完全吸收的条件和扰动在输出中出现的规律,同时也证明扰动值不可能在闭环系统中累积增大.若扰动在产生的第一个生产周期里没有改变原来的事件发生次序,那么,它也不会改变以后所有周期里事件的发生次序和周期长.本文所研究模型的输出对任一参数的灵敏度为100‰或0.

Flexible manufacturing system is one of the most important examplesof discrete event ststems.This paper focuses on behavior of disturbance in thissystem.By analyzing the variations in parameter matrices and in output caused bydisturbance,it presents the condition at which the disturbance will be totallyabsorbed.To a disturbance that can not be absorbed,the paper shows how itbehaves in the output.It is concluded that any small disturbance cannot be ampli-fied in a closed loop system.If a disturbance does not change the event sequencein the first period in which it occurs,it will cause no variance in event sequencein all the later periods.