Practical Implementation of Diagnosis Systems Using Timed Failure Propagation Graph Models

Timed failure propagation graphs (TFPGs) are causal models that capture the temporal aspects of failure propagation in typical engineering systems. In this paper, we present several practical modeling and reasoning considerations that have been addressed based on experience with complex real-time vehicle subsystems. These include handling intermittent faults, reasoning over dynamically commanded test sequences, dealing with the constraints of limited computational resources, and providing automated model verification. We finally present a vehicle subsystem case study.