online read us now
Paper details
Number 2 - June 2025
Volume 35 - 2025
Investigating the problem of misdiagnosis in model-based fault diagnosis
Jan Maciej Kościelny, Michał Bartyś
Abstract
This paper deals with one partly unconscious property of the model-based diagnosis. It discusses occasional contradictions
between diagnoses that are logically correct but, in fact, are not consistent with the physical state of the system being diagnosed. This property is studied and discussed based on the analysis of diagnoses generated by four selected approaches
using binary and trivalent diagnostic signals. The authors attribute the reasons for this inconsistency to the effect of compensation of fault impacts. The analysis and simulation studies carried out confirmed this assumption. To address this
problem, new definitions of diagnoses have been proposed that reflect the different degrees to which diagnoses relate to
the actual physical state of the system being diagnosed. In this context, several new metrics for assessing the quality of
diagnoses have also been proposed. It is pointed out that, from the utilitarian point of view, only those diagnoses that are
logically consistent and have the attribute of physicality are valuable. The problem of misdiagnosis was illustrated on an example of a two-tank system.
Keywords
diagnostic reasoning, misdiagnosis, fault isolation, fault distinguishability