Tactile Electronic Skin With Curved Surface Compensation by In Situ Curvature Self-Sensing

Abstract

Tactile electronic skins with flexibility and good conformability have good application prospects in wearable electronics. However, pseudo-signals are generated when the electronic skin is attached to a curved surface, which affects the pressure detection performance of the electronic skin and limits its application. In this article, we developed a tactile electronic skin that compensates for curved surfaces through in situ curvature sensing and established a pressure, curvature-current model for the compensation of the curvature effect of the electronic skin. The electronic skin can compensate for the measured pressure according to the model and realizes a high-precision sensing capability. It consists of Ag/Ecoflex electrodes, pressure-sensitive materials, and a support layer. The Ag/Ecoflex electrodes with curvature sensing were prepared using screen printing and prestretching. The pressure insensitivity mechanism of the electrodes was analyzed. The effects of curvature on the measurement error of electronic skin were investigated. Experimental results suggest that Ag/Ecoflex electrodes with 80% prestretch have a 21.6/cm−1 curvature sensitivity coefficient and insensitivity to pressure at 0–200 kPa. The measurement errors introduced by curvature can be reduced by compensation. As an application, the skin is attached to the human arm for pressure measurement, through which its great potential is therefore highlighted in curved scenarios such as human prostheses, robots, and flexible airplane skins.