Development of Multi-Indenter Human Stiffness Measurement Devices for Prosthetic Socket Design

Abstract

In this paper, we propose two human body stiffnessmeasurementdevices for the manufacture of wrist socket. The first measurement device is a device with six one-axis indenters, and the second measurement device is a device with four indenter using a parallelogrammechanism.In the case of a measurement device using b a one-axis indenter, the parameters necessary for human body stiffness calculation are obtained by sequentially using the position and force control method for each axis of the indenter as necessary. In the case of measurement device using parallelogram mechanism indenter, the kinematics of the parallelogram mechanism is computed to control the position, and the admittancecontrol controls the force of the indenter pressesthe body. Both devices are attached with a 2-axis potentiometer at the indenter's end, which can be used as a passive 2- degree-of-freedom universal joint to allow the indenter to be indented perpendicular to the measurement site, And the angle between the indentation axis and the motor axis is measured. For this purpose, the mapping between the voltage output and the angle of potentiometerwas obtained by fitting it for each axis. Ultimately, the measurement device was able to measure the stiffness of six regions of human arm.