Measurement of contact and grip force as reference for human hand transmitted vibration evaluation by laser scanning vibrometers

As illustrated in previous works a laser scanning vibrometer can be used to detect vibration transmitted to human body, in particularly vibration velocity on hand skin. The problem still open to investigation of hand mechanical impedance, i.e. the ratio between force and velocity. This parameter, and its distribution on the hand, is of paramount importance for example to build multi input - multi output models or develop and test insulating devices. Another well known fact is that vibration transmission to human hands depends on the overall grip force applied by the subject. In this work film sensors to detect local contact pressure has been analyzed and tested in different situations. The signals of those sensors are then used to calculate mechanical impedance maps of human hands using also results obtained by a scanning laser Doppler vibrometer.