Project Title:

Multi-signal Flowgraphs for Systems Fault Diagnosis

94-1	06.02	1891		

Multi-signal Flowgraphs for Systems Fault Diagnosis

Abstract:

Fault diagnosis in large-scale systems that are products of modern 
technology present formidable challenges to manufacturers and users 
due to the large number of failure sources in these systems, and 
because of the need to quickly isolate and rectify such failures 
with minimal down time. The efficient diagnosis of failure sources 
in such complex systems requires advanced modeling techniques, test 
sequencing algorithms, and their inclusion in user-oriented 
computer-aided design software packages. QUALTECH Systems, Inc. 
proposes to develop novel multi-signal flow graph techniques for 
greater modeling accuracy and diagnostic resolution in 
hierarchically-described modular systems, and the concomitant 
reachability and test sequencing algorithms for fault isolation in 
the presence of multiple faults and asymmetric tests with setup 
costs. Our approach is to employ concepts from information theory, 
heuristic search and graph theory to solve various facets of the 
modeling and test sequencing problems. The resulting modeling 
techniques and algorithms, along with user-friendly interfaces, 
will be integrated into a software package for system testability 
analysis, hybrid on-line/off-line fault diagnosis, and for 
embedding in portable maintenance aids and training tools. As a by-
product, the multi-signal modeling approach has direct applications 
in the quality monitoring of manufacturing processes, and medical 
diagnosis. The development of multi-signal modeling techniques 
would address the issue of model-based reasoning for monitoring and 
diagnosis of problems, raised in subtopic 6.02.

The project would serve to introduce a practical diagnostic tool to 
the electronics, computer and aerospace industries. Other 
applications include the monitoring of manufacturing processes and 
medical diagnostic

Signal Flowgraphs, Multiple Fault Reachability Analysis, Test
Sequencing, Multiple Fault Isolation, AND/OR Graph Search, 
Information Theory, Interactive Graphics

QUALTECH Systems, Inc.
66 Davis Road 
Storrs, CT 06268