Fault Pattern Diagnosis of Discrete-Event Systems by Means of Logical Verifiers

Abstract

In this paper, a diagnosis problem of discrete event systems (DESs) is considered, including fault pattern detection and diagnosability. A fault pattern in a DES is modeled by an automaton that represents the occurrence of complex faults, i.e., the language of the automaton is the objective to be diagnosed. To solve the problem of fault pattern detection, two verifiers are provided. The former, based on state isolation, can perform state estimation in an efficient manner recursively such that at any point during recursion, the states can be isolated. The latter, inspired by the notion of synchronous product, allows us to concisely synthesize and analyze the system information. Comparing these two verifiers, it is found that the two structures are equivalent from the perspective of pattern detection and diagnosability. On the basis of aforementioned verifier structures, we establish their respective diagnosers, and develop algorithms for fault pattern diagnosability.