Drilling with exoskeletons: effect of hand-arm vibration on neurological and muscular outcomes.

Exoskeletons can be used in workplaces where vibrating power tools are applied. The influence of these support systems on vibration exposure and impact remains unclear. In an experimental laboratory study, the influence of two passive exoskeletons for the upper body when working with a drill was compared to a task without exoskeletons. Vibration exposure, transmissibility to the wrist, feed force, muscle activity, muscle fatigue, posture and vibration perception thresholds were measured on 30 subjects. Vibration exposure at the machine handle was higher with both exoskeletons than without an exoskeleton. The vibration perception threshold at 125 Hz shifted less after using the exoskeletons than without using the exoskeletons. When wearing exoskeletons with a strong support torque, increased vibration exposure and higher abduction of the upper arm may occur. The results indicate that exoskeletons reduce the transmission of vibrations in the lower frequency range.