Evaluation of Failure Diagnosis in Conceptual Design of Mechanical Systems

Abstract

This paper discuses a methodology for improving quality and reducing life cycle costs of mechanical systems. The principal concept is that a system can be designed, in the conceptual stages, to be easier to diagnose for failures. To perform this, functional decomposition and form-to-function mapping are utilized to demonstrate the relation of design to diagnosis and for diagnosis itself. Four diagnosability metrics are developed and four hypothetical conceptual designs are evaluated for diagnosability and compared. An example is presented wherein three conceptual designs for a toolhead positioning system are evaluated for diagnosability at two levels of abstraction and the results compared. The area of design for diagnosis offers promise in improving system quality and reducing life cycle cost; research is continuing to refine and integrate the procedures with other aspects of the concurrent engineering design process.