This study demonstrates that a bio-inspired fingertip structure improves the grasping performance of a prosthetic hand. A prosthetic hand attached to a human user requires a higher degree of grasping stability with minimal components compared to a typical robotic hand. Precision grasping tends to be less stable than power grasping; however, the former is used more frequently in daily life. To improve the stability of precision grasping, in this study, we focused on a two-layered elastic structure consisting of epidermis and subcutaneous tissue found in the finger. The efficiency of the two-layered structure, with respect to grasping stability, was evaluated by comparing one-layered and two-layered artificial fingertips. Finally, a two-layered elastic glove was designed based on the stability of the grasping. The stability of the precision grasping was evaluated using the pendulum experiment. The developed glove showed higher stability than the conventional prosthetic hand system.
