Flexible Capacitive Tactile Sensor Array With Truncated Pyramids as Dielectric Layer for Three-Axis Force Measurement

Abstract

This paper presents a flexible capacitive tactile sensor array embedded with a truncated polydimethylsiloxane pyramid array as a dielectric layer. The proposed sensor array has been fabricated with $4\times 4$ sensor units. The measurement ranges of forces in the $x$ -axis, $y$ -axis, and $z$ -axis are 0–0.5, 0–0.5, and 0–4 N, respectively. In the range of 0–0.5 N, the sensitivities of the sensor unit are 58.3%/N, 57.4%/N, and 67.2%/N in the $x$ -axis, $y$ -axis, and $z$ -axis, respectively. In the range of 0.5–4 N, the sensitivity in the $z$ -axis is 7.7%/N. Three-axis force measurement has been conducted for all the sensor units. The average errors between the applied and calculated forces are 11.8% ± 6.4%. The sensor array has been mounted on a prosthetic hand. A paper cup and a cube are grasped by the prosthetic hand and the three-axis contact force is measured in real time by the sensor array. Results show that the sensor can capture the three-axis contact force image both in light and tight grasping. The proposed capacitive tactile sensor array can be utilized in robotics and prosthetic hand applications. [2014-0350]