There is an increasing demand for highly reliable
systems in the safety conscious climate of today’s
world. When a fault does occur there are two desirable
outcomes. Firstly, detection is required to discover
whether functionality at a pre-determined level can be
maintained and secondly, a necessary repair strategy
is sought to minimise system disruption.
Traditional focus on fault diagnosis has been
through a sequential testing procedure or via real time
mechanisms. The limitations have incorporated the
issue of combining real time diagnosis; enabling fast
analysis, with multiple fault causes. These issues are
typical of critical situations within current complex
system architectures.
The diagnostic method suggested in this paper uses
the digraph procedure, which represents the
propagation of inputs through a system. The procedure
involves generating a model; linking nodes referring to
system parameters and determining the relationship(s)
which connect the nodes. Fault detection occurs by
means of tracing through the diagram. The method has
been applied to a water tank system during steady state
operation. Diagnosis is conducted by comparing
readings from sensors in the system with expected
readings, given the system mode of operation. The
results demonstrate the effective use of this technique
for fault diagnosis of the application system.
Keywords: Digraphs, Availability, Failure Detection,
Fault Diagnosis
History
School
Aeronautical, Automotive, Chemical and Materials Engineering
Department
Aeronautical and Automotive Engineering
Citation
KELLY, E.M. ... et al, 2006. Application of the Digraph Method in System Fault Diagnostics. IN: Proceedings of the First International Conference on Availability, Reliability and Security, Vienna, Austria, 20-22 April, pp. 693-700