Shape optimization of screwdriver handle for improving grasping comfort of precision and power grips

Abstract

Improving grasping comfort is a significant factor in enhancing the value of industrial products, as most products are handled by human hands. Our aim was to optimize hand tool shapes and maximize grasping comfort, considering multiple‐shape parameters and grasping types. A screwdriver handle was used as the reference tool for this case study. The measurements of handle length, end diameter, and middle diameter were utilized as the shape parameters of the handle. Twelve participants were included in this study. We measured the participants' subjective perceptions of comfort while grasping the precision and power grips during screw‐driving and screw‐tightening tasks, respectively. The design of the screwdriver handle was formulated as a bi‐objective optimization problem with respect to the grasping comfort of the precision and power grips. A Pareto frontier was determined by optimizing the formulated problem. Well‐balanced and optimal shapes for the precision and power grips were identified.