Design Relations

During preliminary design, designers make critical design decisions based on their experiential knowledge of the characteristics of the components that comprise a system. In particular designers understand the inherent relationship between the form a device will take and the behavior it will exhibit and use this knowledge to estimate characteristics of components and thus evaluate a system. Knowledge of these design relations are gained with experience, but even an experienced designer may not understand the design relations for an unfamiliar device. It is therefore useful to obtain this information automatically and provide it directly to the designer to supplement experience. In this paper we discuss the nature of design relations and show that these relations are inherent in the physics, shaped by the constraints, and dependent upon the context of the design. We describe a method for automatically identifying these relations from a constraint-based model of a device which is based on solving a sequence of constrained optimization problems.