离散事件系统基于模式的安全故障诊断

基于模式的故障诊断方法能将触发系统故障的事件串诊断出来,但在诊断期间系统仍然可能执行被禁止的不安全操作.为此,提出了一种离散事件系统基于S型和T型模式的安全诊断方法.先对离散事件系统基于模式的安全可诊断性进行形式化,再通过构造非法语言识别器和安全诊断器对系统发生的故障模式实施安全诊断,最后分别得到了一个关于S型和T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.

Safe pattern-based diagnosability of discrete-event systems

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.