Noncontact human force capturing based on surface hardness measurement

In this paper, we propose a remote grip force sensing method based on skin surface hardness measurement. The measurement system is composed of an airborne ultrasound phased array and a laser displacement sensor. The surface hardness distribution of a human hand is estimated by optically measured surface vibration amplitude induced by the ultrasound radiation pressure. The realtime grip force is estimated using the relationship between the hand surface compliance and the grip force which is obtained experimentally in advance. The feasibility of grip force estimation is confirmed for a gripping hand keeping a constant posture.