J. Darzentas et al. (Eds.): SETN 2008, LNAI 5138, pp. 160–172, 2008. © Springer-Verlag Berlin Heidelberg 2008 Fuzzy Representation and Synthesis of Concepts in Engineering Design Vassilis C. Moulianitis 1,2 , Nikos A. Aspragathos 2 , and Argiris J. Dentsoras 2 1 Department of Product and System Design Engineering, University of the Aegean, 84100, Ermoupolis, Syros, Greece 2 University of Patras, Mechanical Engineering and Aeronautics Department, 26500, Patras, Greece {moulian,asprag,dentsora}@mech.upatras.gr Abstract. In the present paper a new mathematical fuzzy-logic-based formula- tion of the design objects and the rules that govern a design problem during the conceptual design phase is presented.. A procedure for the automatic generation of degrees of satisfaction of the design specifications for each feasible solution - subjected to design constraints - is introduced. A table containing the satisfac- tion degrees is used for the derivation of the set of all possible synthesized solutions. The determination of this set, which is a subset of the set of the syn- thesised solutions, is based on a suitable partition of the Euclidean space. An il- lustrative example of a knowledge based system for the conceptual design of grippers for handling fabrics is presented. The advantages of this model are re- vealed via a comparison with previous implementations of the conceptual de- sign phase based on crisp production rules or certainty factors. Keywords: Conceptual Design, Fuzzy Logic. 1 Introduction It was only by the middle of the 20 th century when design became the focus point of many researchers aiming to the formulation of a rigorous and scientific basis for what had been an intense human intellectual activity throughout the centuries. Since then, design philosophies, models, methods and techniques have been developed [1, 2, 3] and different approaches have been worked out concerning the nature of the design. The design models have tended to fall within two main classes: prescriptive and de- scriptive. Prescriptive models have been used to look at the design process from a global perspective covering the procedural steps, and have been based on either the design process itself or on the product attributes. The descriptive models are related to the designer’ s activities during the design process. Recent advances in the field of artificial intelligence (AI) offer the scientific basis to clarify and articulate concepts of design so as to establish an advanced framework for the design research, towards the so called computational models. A survey on the application of soft computing (SC) techniques in engineering design is presented in [4]. Design activities encompass a spectrum from routine design, through variant design to creative design of new arti- facts. While the routine design is possible to be computable to a great extent, it is very difficult to model adequately the creative design.