Dome-Structure Array from Pre-Strained Extendable Mesh for Tactile Sensing Without Crosstalk and Lateral Strain Interference.

Abstract

Flexible tactile sensors have received significant attention for use in wearable applications such as robotics, human-machine interfaces, and health monitoring. However, conventional tactile sensors face challenges in accurately measuring pressure because vertical deformation is induced by Poisson's ratio in situations where lateral strain is applied. This study shows a strain-insensitive flexible tactile sensor array without the crosstalk effect using a highly stretchable mesh. This sensor is fabricated by assembling a sensing layer in which sensing cells form in each hole of an elastomer mesh and liquid-metal-based stretchable electrode layers. Stretching deforms the soft mesh layer with little effect on the rigid sensing cell array, which results in the sensor being insensitive to uniaxial strain. In addition, each sensing cell is formed in a dome shape, which resulted in a sensor exhibiting high sensitivity (7.80 kPa^-1) over a wide sensing range (<160 kPa). The proposed design also allows each sensing cell to be electrically separated, enabling the pressure measurements without cell-to-cell crosstalk. Based on these characteristics, strain-insensitive pressure monitoring is demonstrated to prevent carpal/cubital tunnel syndrome by attaching the device to the joints, which suggests its potential application in healthcare.