Developing a hand sizing system for a hand exoskeleton device based on the Kansei Engineering method

This study aimed to identify the customers’ requirements for a hand rehabilitation exoskeleton device using the Kansei Engineering approach and propose improvements. The Kansei Engineering approach was used to extract the design attributes for a hand rehabilitation exoskeleton device by conducting an in-depth interview with 3 physical therapists. The Kano questionnaire survey investigated 25 participants with hand rehabilitation experience. The Kano classification results found three attractive factors and corresponded it to the design attributes of the evaluation grid method results that were suitable (size), flexible (controllability), and light (weight). The principal component analysis results indicated three components can be considered as the improvement categories; functions, structure-texture, and appearance of the hand exoskeleton device. The new functional and structural designs were proposed in a previous study. This study collects 110 male participants’ hand anthropometric data to establish a hand sizing system as a design improvement (suitable attribute). The 3D and manual measurements were obtained for 63 hand dimensions with an open palm posture. The 14 dorsal length dimensions with three bent finger postures were also manually measured. The results showed that the MADPrecision\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{MAD}}_{\text{Precision}}$$\end{document} (mean absolute difference) of 3D measurement is smaller than that of manual measurement, indicating better reproducibility of 3D scanning. The MADAccuracy\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{MAD}}_{\text{Accuracy}}$$\end{document} of all dimensions are within the 1 mm of the referenced ISO 20685 criteria. Significant differences were found in the 14 dorsal hand length, showing that databases should explicitly state the aspect (dorsal or palmar) where dimensions have been of measurement. The 77 hand dimensions were taken into consideration to develop a hand sizing system using the clustering results. The two-level self-organizing map method was performed and 3 handshape types and 8 sizes were extracted. The coverage rate of the sizing system was over 85%. These results provide useful information for designing and manufacturing for hand-related products.