A New Force-Decoupling Triaxial Tactile Sensor Based on Elastic Microcones for Accurately Grasping Feedback

Tactile sensor capable of detecting both normal and tangential forces is essential for the next-generation robotic electronics. However, designing a reliable triaxial tactile sensor to decouple the normal and tangential forces is still a challenge for current research. Herein, a capacitive triaxial force sensor based on a microcone dielectric layer together with the force decoupling method is proposed. The lateral and vertical displacement of the top electrode relative to the bottom electrodes under the action of external forces can be perfectly detected according to the capacitance variations. The microcone-structured sensor combined with the new decoupling method leads to a high sensitivity of 3.5 kPa(-1) for normal force in a low-pressure range of 0--50 Pa and 0.134 N-1 for tangential force in 0-0.5 N, and a fast response time of 26 ms. The sensors mounted on the fingers of a robotic arm can provide effective tactile information during the grasping task. Finally, a conceptual 3 x 3 tactile sensor array is fabricated and verified for spatial pressure mapping. This work provides new insight into piezocapacitive tactile sensor design and shows its great potential in robotic applications.

Automated summary

A capacitive triaxial force sensor based on microcone dielectric layer and force decoupling method is proposed in this study, which can perfectly detect the lateral and vertical displacement of the top electrode relative to the bottom electrodes under external forces. The sensor structure along with the new decoupling method exhibits high sensitivity (3.5 kPa(-1)) for normal force in a low-pressure range and fast response (0.134 N-1, 26 ms) for tangential force. By mounting the sensors on the fingers of a robotic arm, effective tactile information during grasping task can be provided. Furthermore, a 3x3 tactile sensor array is fabricated for spatial pressure mapping. This work provides new insights into the design of piezocapacitive tactile sensors and demonstrates their great potential in robotic applications.