离散事件系统故障的极小观测序列

Minimal Observation Sequences of Faults in Discrete Event System

为了提高可诊断离散事件系统故障的在线诊断效率,本文从判定故障发生的可观测事件的角度,提出了故障极小观测序列方法.文中选取有限状态自动机对离散事件系统进行建模.首先,在离线状态下,建立系统的故障模型,以排除对于判定系统故障无关的路径.然后,根据故障模型进一步建立判定系统故障的极小观测序列模型.当离散事件系统在线诊断时,仅需将逐步增加的在线观测事件序列与故障的极小观测序列模型进行比对.若能找到满足该模型的任何一条路径,则说明路径终止状态上故障标签对应的系统故障发生;否则,说明系统无故障发生.文中对可诊断离散事件系统进行实验对比,通过故障的极小观测序列模型能尽快判定有无故障发生,以及发生了哪些故障.该模型能有效地缩小系统在线诊断的时间,提高系统在线诊断的效率.

In order to improve the efficiency of online diagnose of faults in discrete event system,from the viewpoint of the observable events judging occurrence of faults,this paper proposed a method called minimal observation sequences of faults.The finite state automaton was selected to model the discrete event system.First,a fault model of system was established in the offline,which was used to exclude the path independent of the system failure.Then,a minimal observation sequence model of faults was established according to the fault model.When the discrete event system is diagnosed online,it is necessary to compare the observations received by sensors with the model of minimal observation sequences.If any path in the model is found to satisfy the online observations,the fault in the termination state of the path will be described.Otherwise,no fault occurs.By comparing with the experiment results,the model of minimal observation sequences of faults can be used to determine the occurrence of faults as soon as possible.That is to say,the model for the system can find the faults timely and save the cost of online diagnosis.