Evaluation of handheld products by computing user hand fatigue

In this study, we propose a method to evaluate handheld devices at the design stage. Many researchers have carried out highly reliable evaluations of the comfort level in grasping motions. Nevertheless, the presently available product evaluation criteria based on finger movement are still unsatisfactory. Accordingly, this study proposes a new concept called angle-based fatigue (ABF), which can use finger movements to evaluate the fatigue felt by the user at the product design stage. The proposed method is expected to maximize efficiency at the product design stage because it can easily and rapidly calculate the degree of fatigue experienced by a user when using a particular design.