RAPPER: The Copier Modeling Project

The programme of research of model-based diagnosis is based on several assumptions, foremost of whichis the availability of component-based modelsof the system being diagnosed. This assumption has beenfairly innocuous for diagnosis of networks of combinatorial devices, for which the construction of models with appropriate levels of discriminatory power has been easy. A priori, however, there is no reason to believe that it will be possible to easily construct models of appropriate generality, power and usability for complex, real-time, computational electro-mechanical systems. This paper reports on a project we started three years ago to construct a component-based model for the input document-handler of a photocopier. Our goal was to develop a model that was rich enough to allow the generation of diagnostic trees with the same discriminatory power as existing documentation (RAPs, orRepair Action Procedures), which are by and large constructed manually. This goal has been met in principle, but we have learnt several useful lessons along the way.