Verification of Codiagnosability for Decentralized Diagnosis of Discrete Event Systems Subject to Permanent Sensor Failures

Abstract

We consider a decentralized failure diagnosis problem for discrete event systems. Each local diagnoser makes a diagnosis decision based on local event observations. A sensor that detects the occurrence of an event may possibly fail due to, for example, aging degradation. It is desirable that the occurrence of any failure string can be correctly detected in the presence of sensor failures. In the authors' previous work, a new notion of codiagnosability was introduced, which guarantees that any occurrence of a failure string can be correctly detected by a decentralized diagnoser within a bounded number of steps even if a permanent sensor failure occurs. In this paper, we develop a method for verifying this codiagnosability property subject to permanent sensor failures.