Direct measurement for hand-transmitted vibration of human fingers-hand-arm system in the zero-gravity environment

Abstract

This paper proposes a direct measurement method to obtain the mechanical impedance and vibration transmissibility of the fingers-hand-arm system when operating power tools based on zero-gravity environment simulations. A hand-transmitted vibration measurement system with a suspension device for zero-gravity simulation is first built. The two-step dynamic measurement method is used to measure the dynamic force and acceleration of fingers and palm directly. The forearm and upper arm’s acceleration is also measured using the two-step dynamic measurement method. Based on eliminating the effect of the handle’s effective mass on the mechanical impedance, the mechanical impedance and vibration transmissibility of the human fingers-hand-arm system during the actual operation of the power tool are calculated by using the measured data, and the biodynamic response characteristics of the fingers-hand-arm system at different frequencies are analyzed. The results show that, under the condition of the ISO standardized operating posture (ISO 10819, 2013), the mechanical impedance and vibration transmissibility curves obtained by direct measurement of 21 subjects have remarkable consistency respectively. Compared with the experimental data in the gravity environment, the mechanical impedance and the vibration transmissibility obtained based on the zero-gravity simulation are more consistent with the working conditions of the on-orbit maintenance power tools.