An integration of a QFD model with Fuzzy-ANP approach for determining the importance weights for engineering characteristics of the proposed wheelchair design

Abstract

A wheelchair design with a nested seat back and hand-rest was proposed and ergonomically analyzed, with the objective of decreasing the likelihood of poor and awkward body postures for both the disabled user and his/her companion. The proposed design was validated by integrating a Quality Function Deployment (QFD) framework with a Fuzzy Analytic Network Process (FANP) to determine the degree of importance of the engineering characteristics. In this study, the influence of this integration on determining weights that prioritize engineering characteristics (ECs) was highlighted by taking into consideration the mutual dependence between customer needs (CNs) and ECs and the inner dependence amongst them. This study focused on utilizing FANP methodology, in which triangular fuzzy numbers (TFNs) were used to represent the degree of importance of CNs and ECs, since human judgments of the intensity of preference for these attributes are subjective, vague, and uncertain. Regarding the importance weights for engineering characteristics of the proposed wheelchair design, it has been found that the quality of material scores the highest weight compared to other ECs, with an overall importance weight of 0.43. This result differed from that one obtained using the QFD model without integration, in which the method of design came in first position. The integrated approach proved to be a promising tool in solving fuzzy decision-making problems in different fields and in several applications such as product development and design for ergonomics. As the FANP approach is not popular in the product development/selection field, this study will expand its employment by decision makers in facilitating the evaluation process where there are interrelated factors under an uncertain environment.