Fault Diagnosis of Timed Discrete Event Systems

In this paper, we consider partially observable timed discrete event systems (DES) endowed with a single clock that is reset at each event occurrence. A time interval with integer bounds is associated with each transition specifying at which clock values it may occur. This work deals with the fault diagnosis problem of such timed DES, assuming that faulty behaviours are described by means of timed transitions. We present a zone automaton that provides a purely discrete event description of the behaviour of the timed DES with faults and construct a fault recognizer as the parallel composition of the zone automaton with a fault monitor that recognizes the occurrence of faults. The diagnosis approach allows one to compute the diagnosis state for each timed observation, which consists in a timed sequence of observed events.