Design for diagnostics and prognostics:a physical- functional approach

Abstract

This paper describes an end-to-end IntegratedVehicle Health Management (IVHM) development processwith a strong emphasis on the COTS software tools employedfor the implementation of this process. A mix of physicalsimulation and functional failure analysis was chosen as aroute for early assessment of degradation in complex systemsas capturing system failure modes and their symptomsfacilitates the assessment of health management solutions for acomplex asset. The method chosen for the IVHM developmentis closely correlated to the generic engineering cycle. Theconcepts employed by this method are further demonstratedon a laboratory fuel system test rig, but they can also beapplied to both new and legacy hi-tech high-value systems.Another objective of the study is to identify the relationsbetween the different types of knowledge supporting the healthmanagement development process when using togetherphysical and functional models. The conclusion of this lead isthat functional modeling and physical simulation should not bedone in isolation. The functional model requires permanentfeedback from a physical system simulator in order to be ableto build a functional model that will accurately represent thereal system. This paper will therefore also describe the stepsrequired to correctly develop a functional model that willreflect the physical knowledge inherently known about a givensystem