Abrupt and Drift-Like Fault Diagnosis of Concurent Discrete Event Systems

Abstract

Discrete Event Systems (DES) are dynamical systems that evolve according to the asynchronous occurrence of certain changes called events. This paper proposes a modular approach for abrupt and drift-like fault diagnosis of concurrent DES. In this class of DES, the system consists of several components or subsystems that operate concurrently. Each component is modeled as a sequence of predetermined actions as well as the responses to these actions. Each component model represents the desired (nominal) system behavior. An abrupt fault is viewed as a violation of the component desired behavior. While a drift-like fault is viewed as a drift in the normal characteristics of component response to actions. An indicator measuring the change in the response characteristics of the component is used to detect a drift. This detection can be then used to warn a human operator when the component behavior starts to deviate from its normal behavior. The proposed approach is illustrated using a manufacturing system.