Qualitative Modeling Is the Key to Automated Diagnosis

The paper presents objectives and results of a case study in computer support for failure mode and effects analysis and for the creation of repair manuals in the domain of automotive systems. Model-based prediction and diagnosis reflect the requirements of these tasks. More specifically, qualitative models of system components are necessary for both capturing the available knowledge and achieving the desired coverage and granularity of the analysis results. We describe models for parts of the anti-lock braking system (ABS) and the electronic diesel control (EDC), focusing on a qualitative approach to compositional modeling of the involved electrical circuits. The summarized results of the case study demonstrate the necessity and utility of qualitative models for the successful application of automated diagnosis to industrial problems.