| This thesis developed a multidisciplinary design approach for integrating ergonomics and engineering design technology (QFD). A modified HoQ (House of Quality) matrix adapted from QFD was proposed and utilized to systematically identify the critical ergonomic design area corresponding to functional user requirements as well as affective needs of user. A case study of screwdriver design was conducted to demonstrate the applicability of the proposed design methodology. As a result, 26 user satisfaction attributes were identified and classified into 3 user satisfaction dimensions (performance, physical interaction, affective image/impression) based on survey data using a total of 57 participants. With respect to level of experience, participants were divided into two groups. The result of comparison of two groups revealed that there was a clear distinction between two groups in terms of user needs or expectation. Regarding the relative importance of user needs or expectation, inexperienced users focused on the affective image/impression-related user needs while experienced users relatively focused on functionality-related user needs rather than affective image/impression. However, ranks of the user needs were significantly correlated between two groups. Interestingly, design priority of experienced users was distinctly divided while that of inexperienced users scattered across 25 product design attributes. Among the 25 product design attributes, physical handle characteristics were identified as critical ergonomic design areas. This thesis also developed a comprehensive ergonomic evaluation methodology comprising objective measurements and subjective measures associated to user satisfaction. A case study of screwdriver evaluation was conducted in order to prioritize five different screwdriver designs using two experimentations (maximum torque task and constant torque task) and a product-interactive questionnaire. The result, based on data using a total of 15 participants, indicated that the priority of screwdrivers varied over objective measurements and subjective evaluation. An integrated design priority measure, which incorporated 4 objective measures into subjective evaluation criteria corresponding to 26 user satisfaction attributes, was proposed and successfully accessed the priority of five different screwdriver designs from a holistic perspective. Finally, it is expected that the proposed ergonomic design and evaluation methodology could be applied to other hand tools. |
