Knowledge-based approach and system for assembly-oriented design, Part II:the system implementation

Assembly is one of the most important stages for product development. Assem bly-oriented design (AOD) is a new approach to designing assemblies, which uses a number of design and analysis tools to help the designer plan out an d analyze candidate assembly schemes prior to having detailed knowledge of the geometry of the parts. Using this approach. many assembly schemes can b e inexpensively evaluated for their ability to deliver the important charac teristics of the final product. This research proposes a knowledge-based ap proach and develops an expert design system to support top-down design for assembled products. The presentation of research report is divided into two parts: the knowledge-based approach (Part I) and the knowledge-based exper t design system (Part II). This paper is the second part of the report (Par t II). It will focus on the development of knowledge-based expert design sy stem for assembly oriented design. The knowledge-based assembly oriented de sign system, i.e., the assembly oriented design expert system (AODES) is co nstructed to integrate assembly modeling and design, assembly planning, ass emblability analysis and evaluation within a concurrent engineering environ ment. This intelligent system is implemented by integrating object-oriented representation, constraint-based modeling, rule-based reasoning, truth mai ntenance, and interfacing to database management system and CAD module, in which fuzzy logic based knowledge representation and inference technique ar e also applied to deal with uncertain data and knowledge in the design proc ess. The developed system differs from the existing systems adopting part-f irst bottom-up modeling technique, in which a comprehensive intelligent fra mework is used for assembly modeling and design in a top-down manner from t he conceptual level to the detailed level. It is able to help obtain better design ideas, provide users with suggestions so as to create and improve a design, and therefore give users the possibility to assess and reduce the total production cost at an early stage during the design process. Through the use of the system, the concurrent engineering knowledge can be effectiv ely incorporated into the assembly design process in an integrated manner. A case assembly design shows that the intelligent modeling and design syste m is feasible. (C) 2001 Elsevier Science Ltd. All rights reserved.