Product Models and Reusability

This paper describes and explains the rationale behind the product model that is employed in the configuration design tool SyDeR (System Design for Reusability, [SDR98]). its name indicates, SyDeR stresses the reuse of system designs in later design projects. The field where SyDeR is applied is configuration design lbr products for which there is not a complete, fixed set of components, but rather a set of previous designs from which one can be chosen to be reused and/or adapted to the current configuration design problem. This sub-field of configuration design is of major economic importance, as e.g., the design of railway rolling stock or trucks fall into this category. Importance of reusability Configuration design takes it for granted that components can be reused in any product configuration. As we had to learn in earlier application studies for configuration design, not every product family meets these requirements. So, it is an important issue to design components and product families in a way that allows to use them in configuration design. Beyond configuration design in the narrower sense, reusing a component design also saves the time to design it again and the development risks that come with a new development effort. Reuse saves money in development as well as in later stages of the process chain (no new manufacturing or testing equipment is needed, e.g.). Reusability of product and component designs can be * Copyright ©1999, American Association for Artificial Intelligence (www.aaai.org). Allrights reserved significantly increased by intelligent software tools that offer advice on how to reuse and adapt previous component designs as well as to design components for reusability in the first place. Crucial to reusability is the way the product and its components are modelled. This paper explores how a product model that enables reusability should look like. Before going into details, we would like to clarify our terminology. There is a large vocabulary for the components of a product (parts, components, assemblies, modules, etc.), which can be a source of confusion. ’In the SyDeR product model, we decided to call these objects systems. We will stick to this decision throughout this paper and kindly ask the reader to accept this (somewhat abstract) choice for the next six pages. In the paper, we will first look at a product model that aims straightforward at describing a product without paying much attention to reusability. In the following chapters, we will describe extensions to this simple model that step by step improve reusability. Modelling product structure as if reusability