3-D mechanical impedances distributed at the fingers and palm of the hand

Abstract

The driving-point biodynamic responses distributed at the fingers and palm of the hand in three orthogonal directions were examined. Seven healthy male subjects participated in the study and the experiment was carried out on a novel 3-D vibration test system. In the study, each subject was instructed to maintain grip and push forces at 30∓5 N and 50∓8 N, respectively, with his dominant right hand with elbow angle between 90° and 120° and shoulder abduction between 0° and 30°. Despite the considerable inter-subject variability, the responses measured along each axis consistently exhibit two magnitude peaks in the frequency range considered, which can be approximately considered as dominant resonance frequencies of the hand-arm system. The percent power absorbed in the fingers increases with the increase in frequency as the vibration becomes more concentrated in the hand and finger response becomes more independent to the remaining parts of the system.