Soft-Material-Based Highly Reliable Tri-Axis Tactile Thin-Film Sensors for Robotic Manipulation Tasks

• Published in: 2021 IEEE Sensors pp. 1 - 4
• Main Authors: Tsukamoto, Kei, Ebisui, Akira, Goto, Tetsuro, Sakakura, Yoshiaki, Kobayashi, Ken, Sato, Satoshi, Kamei, Takahiro, Imai, Yutaka, Nomoto, Kazumasa
• Format: Conference Proceeding
• Language: English
• Published: IEEE 31.10.2021
• Subjects: collaborative robots; dexterous manipulation; Force; Force measurement; Materials reliability; Robot sensing systems; Sensitivity; shear force detection; soft material; soft robotics; tactile sensor; Tactile sensors; Task analysis; tri-axis force sensor
• ISSN: 2168-9229
• DOI: 10.1109/SENSORS47087.2021.9639695

Tactile sensing is essential for intelligent robot control such as for dexterous manipulation tasks. To provide reliable sensors that can withstand industrial applications, we have developed a soft and thin-film tactile sensor capable of detecting tri-axis force components including normal and shear forces. The thickness of the sensor is 5.5 mm, and the sensor can be easily attached on an end-effector. Two layers of capacitive-sensing-electrode arrays sandwiching an elastomer layer of 2-mm spatial resolution are embedded in soft material, and output signals are distributed. To measure the external force vector, center-of-distributed-signal calculation was conducted. Our sensor exhibited linear behavior within 0.1 to 10 N for normal force and 0.1 to 4 N for shear force. With high reliability, sensor sensitivity did not change over ±10.0% even after one million repetitive keystroke cycles and one million repetitive shear-movement cycles. To determine the sensor's effectiveness for manipulation tasks, a grasping-force control experiment was conducted using sensor signal feedback, and multiple local-shear-force vectors were successfully calculated using area-divided methods.