Diagnosis of Continuous Valued Systems in Transient Operating Regions

Pieter J. Mosterman and Gautam Biswas
Center for Intelligent Systems


Present day machines and processes incorporate embedded control, i.e., they are continuous physical systems controlled by discrete digital processors. The complexity of these systems with the increased demands on their reliability motivate the need for adding monitoring and fault isolation capabilities in the embedded processors. This paper develops monitoring, prediction, and fault isolation methods for complex dynamic systems affected by abrupt faults. The transient behavior in response to those faults is exploited in a qualitative framework, using parsimonious topological systems models developed in the bond graph framework. Predicted transient effects of hypothesized faults are captured in the form of signatures that specify future behavior for the fault with higher order time-derivatives. The dynamic effects of faults are analyzed by a progressive monitoring scheme till feedback effects modify the initial transients significantly, and the detection mechanisms have to be suspended in favor of steady state analysis. This methodology has been successfully applied to monitoring of the secondary sodium cooling loop of a fast breeder reactor.

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