Safe diagnosability for fault-tolerant supervision of discrete-event systems

Paoli, Andrea and Lafortune, Stephane (2005) Safe diagnosability for fault-tolerant supervision of discrete-event systems. Automatica, 41 (8). pp. 1335-1347. ISSN 0005-1098

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The problem of achieving fault-tolerant supervision of discrete-event systems is considered from the viewpoint of safe and timely diagnosis of unobservable faults. To this end, the new property of safe diagnosability is introduced and studied. Standard definitions of diagnosability of discrete-event systems deal with the problem of detecting the occurrence of unobservable fault events using model-based inferencing from observed sequences of events. In safe diagnosability, it is required in addition that fault detection occur prior to the execution of a given set of forbidden strings in the failed mode of operation of the system. For instance, this constraint could be required to prevent local faults from developing into failures that could cause safety hazards. If the system is safe diagnosable, reconfiguration actions could be forced upon the detection of faults prior to the execution of unsafe behaviour, thus achieving the objective of fault-tolerant supervision. Necessary and sufficient conditions for safe diagnosability are derived. In addition, the problem of explicitly considering safe diagnosability in controller design, termed "active safe diagnosis problem", is formulated and solved. A brief discussion of safe diagnosability for timed models of discrete-event systems is also provided. © 2005 Elsevier Ltd. All rights reserved.

Keywords:Accident prevention, Discrete time control systems, Finite automata, Process control, Set theory, Transfer functions, Discrete event systems, Fault diagnosis, Fault tolerant control, Finite state machines, Supervision, Control system analysis
Subjects:C Biological Sciences > C700 Molecular Biology, Biophysics and Biochemistry
C Biological Sciences > C500 Microbiology
Divisions:College of Science > School of Life Sciences
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ID Code:15887
Deposited On:04 Nov 2014 14:45

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