Conceptual graphs in constraint based re-design

Abstract

This paper elaborates on the use of conceptual graphs for the representation of different types of objects and constraints in a re- design support system. Conceptual graphs, or conceptual structures, have been proposed for use in natural language processing and for representing mental models. However, recently they have also been proposed for use in the field of CAD/CAM. Conceptual graphs are graphs with two different kinds of nodes: concepts and conceptual relations. ReAesign support involves the modelling of assemblies and components, which on their turn are composed of features and geometric elements. The assemblies, components, features and geometric elements are represented by the concepts in the conceptual graph. The constraints between these entities are represented as conceptual relations. Constraints, such as geometric, kinematic, and manufacturing constraints are represented using conceptual graphs. Thus, conceptual graphs provide for an elegant way of representing hods functioning and manufacturing constraints. Constraints are satisfied using a 'mukibrid' constraint satisfaction approach, employing geometxy related domain knowledge for the geometry related constraints and an algebraichmmeric approach for the remaining constraint equations. The combination of the constraint satisfaction mechanism and the conceptual graphs allows for a unified way of handling assembly, comprnent and feature related information, Conceptual graphs are not only used in representing assemblies, components, features, and constraints, but also in supporting a mixed topiown and bottom-up design style,