SPA-based approach to decision making in conceptual design

Conceptual design selection is the most critical part of the design process as it determines the direction of subsequent design stages. In addition, it is a difficult task because available information for decision making at this stage is imprecise and subjective. Set pair analysis (SPA) is the very tool to deal with concept design selection. In decision making process, first identify weights with identity matrix derived from decision maker´s (DM´s) judgment matrices, second identify the identity, discrepancy and contradiction between alternatives and the ideal solution, and third identify closeness. The greater the closeness, the more the alternative approaches to ideal solution. Finally, taking speed reducer design scheme for example, this paper elaborates ranking procedure, and by comparison of the SPA´s result with fuzzy comprehensive evaluation, further illustrates the effectiveness and practicability of the proposed approach.