Improved engineering design concept selection using fuzzy sets

摘要

Conceptual design is important in producing a successful product, because a poor design concept can rarely be compensated for at the later design stages. Pugh's concept selection method has been widely used in industries to help designers to select promising design concepts. However, experience shows that many designers feel uncomfortable with adopting the highest scoring result, because the Pugh's concept selection method does not provide enough information to allow designers to put faith in the obtained result. The objective of this paper is to extend the Pugh's concept selection method with fuzzy set theory to measure the quality of a chosen concept. The performance ratings of a design concept are represented with linguistic terms that can be further characterized with fuzzy sets. The proposed concept selection model produces a partial order of design concepts based on the valued preference relations between different design concepts. The best design concepts can be identified for continuous improvement or further development in the next design stage. In addition, three measures, including the nondomination index, the imbalance index, and the optimality index, are developed to help designers evaluate the quality of the candidate concepts and to determine possible ways for further improvement. An outpatient syringe example is used to illustrate the approach developed