Computation of Reduced Diagnosers for the Fault Diagnosis of Discrete Event Systems

Abstract

Many complex systems in different areas such as manufacturing, telecommunications or transportation can be modeled as discrete event systems (DES). In this paper, we consider the fault diagnosis for DES which is concerned with detecting fault occurrences in a DES within a bounded number of event occurrences by a diagnoser automaton. Hereby, such diagnoser is able to observe a subset of the system events and the maximum required number of event occurrences until a fault detection is denoted as the worst case detection delay (WCDD). The main contribution of the paper is an approach for reducing the number of required observations for fault diagnosis without increasing the WCDD. As a result, it is possible to determine a diagnoser with a small size which is essential in practical applications. We first develop an algorithm for computing the WCDD and then adapt an approach for the reduction of the observable event set in order to obtain a reduced diagnoser. The application of our method to a communication system example demonstrates its practicability.