A Small and Low-Cost 3-D Tactile Sensor for a Wearable Force Plate

In this paper, a new 3-D tactile sensor is proposed for measuring triaxial ground reaction force (GRF) distribution. A pressure-sensitive electric conductive rubber (PSECR) and compact pectinate circuits were used to design the sensing cells of the sensor, making it possible to implement a low-cost and compact system without a complex 3-D structure. Moreover, to tailor the application for measuring human GRF, we adopted the use of elastic rubber as the contact interface of the sensor in order to realize a comfortable human-sensor interface. Calibration and test experiments were conducted to characterize the developed sensor, and a small triaxial force sensor (Tec Gihan, Japan) as well as a six-axial force sensor (Nitta Corporation, Japan) were used as verification measurement devices. Coupling effect tests were performed to calculate cross-sensitivity of the sensor. The experimental results of repeatability, nonlinearity, hysteresis, and dynamic tests indicate that the sensor is feasible for implementing 3-D tactile measurement.