A Wearable Force Plate Designed Using Pressure Sensitive Electric Conductive Rubber

Abstract

To perform 3D ground reaction force (GRF) and moments measurement with a comfortable interface for the foot, this paper presents a new 3D force sensor cell designed using pressure sensitive electric conductive rubber (PSECR). A wearable force plate with a four-support mechanism was proposed for measuring triaxial forces and moments. A compact electrical hardware system including amplifier modules, conditioning circuits, and then a micro-computer controller was developed and integrated into the sensor system. A shoes-based sensor system composed of two developed force plates was constructed for GRF and moment measurement. Calibration experiments were conducted, and a stationary force plate was used as a reference device to verify the measures of GRF and moment using the sensor system in trials by a normal walking speed. The results show a good correspondence between the developed sensor system and the reference system, which was examined by a root mean square (RMS) difference of 7.2N for x-axial force, 11.1N for y-axial force, and 9.5N for z-axial force. The RMS difference of the measured x-, y-, and z- directional moments was 6.4Nm, 1.9Nm, and 1.4Nm, respectively.