Spherical fuzzy bipartite graph based QFD methodology (SFBG-QFD): Assistive products design application

Assistive product (AP) aims to provide supplementary treatment for patients' physical function and daily activities to improve their functional status. One challenge in the AP design is prioritizing design requirements (DRs) based on patient requirements (PRs) involving diverse and variable interaction behaviors. This work developed and applied a quality function deployment method based on the spherical fuzzy bipartite graph (SFBG-QFD) to comprehensively consider the dependency relationship between PRs and DRs during AP design. Specifically, a spherical fuzzy bipartite graph is constructed in the PR-DR relationship matrix. The projection algorithm generates the one-mode spherical fuzzy graphs of PRs and DRs, reflecting the internal relationship of PR-PR and DR-DR pairs. Subsequently, the interaction influence of PRs and DRs is defined as an additional criterion for the QFD method. Through the SFBG-QFD method, designers can better consider the uncertainty of interaction between different types of requirements and make more reliable decisions. The effectiveness of the proposed method is verified through the AP design for pneumoconiosis patients, and the stability and potential of the proposed method are emphasized through comparative studies.