离散事件系统基于模式的安全故障诊断

Safe pattern-based diagnosability of discrete-event systems

中文关键词  离散事件系统  故障诊断  故障模式  安全故障诊断

英文关键词  Discrete-event systems, fault diagnosis, fault patterns, safe diagnosability

中文摘要

      近年来，离散事件系统的故障诊断研究引起了国内外众多学者的广泛关注。尽管现有基于模式(Pattern-Based)的故障诊断方法能够将触发系统故障的事件串（称为故障模式）诊断出来，但是在诊断期间系统仍然可能执行某些被禁止的不安全操作。为此，本文针对目前最常用的 型和 型两种模式的故障诊断的安全性问题，分别提出了一种相应的离散事件系统基于模式的安全故障诊断方法。先引入 型和 型两种故障模式的可诊断条件和安全性条件，对离散事件系统基于模式的安全可诊断性进行形式化；再通过构造一个非法语言识别器对非法操作进行识别，并在此基础上构建相应的安全诊断器，对系统发生的故障模式实施安全诊断；最后，我们分别得到一个关于 型和 型模式的系统安全可诊断性的充分必要条件，实现了离散事件系统基于模式的安全故障诊断。该方法不仅能够将触发系统的故障模式诊断出来，还保证了系统在诊断期间不会执行任何被禁止的不安全操作。

英文摘要

      In recent years, the problem of fault diagnosis for discrete-event systems (DESs) has received considerable attention due to the practical and theoretical importance. Although the existing pattern-based diagnosis methods can detect the fault patterns that cause systems failed, but the system may still perform the prohibited unsafe operations during the diagnosis. For this problem, this paper aims to propose an approach for safe diagnosability of DESs based on S-type and T-type of fault patterns. The diagnosability condition and the safety condition of the S-type and T-type of fault patterns are introduced, and the notion of safe pattern-based diagnosability of DESs is formalized. After constructing the recognizer of illegal language to identify the sequences of the forbidden operations, the safe diagnoser is constructed to implement safe diagnosis of fault patterns for the given system. In particular, a necessary and sufficient condition of safe pattern-based diagnosability for is proposed for the S-type and T-type patterns, respectively. It is guaranteed that not only each fault pattern causing the system failed can be detected with a finite delay but also the detection may be completed before any unsafe forbidden operation is executed.