Probability of faults for partially observed Timed PNs with temporal constraints

Abstract

This article concerns faults detection and isolation for timed stochastic discrete event systems modeled with partially observed Timed Petri nets and temporal constraints. Events occur according to arbitrary probability density functions. The models include the sensors used to measure the events and markings and also the temporal constraints to be satisfied by the system operations. These temporal constraints are defined according to tolerance intervals specified for each transition. A fault is an operation that ends too early or too late. The set of marking trajectories consistent with a given measured trajectory is first computed. Then, the probability that the temporal constraints are unsatisfied is estimated for any consistent trajectory and the probability that a temporal fault has occurred is obtained as a consequence.