Multifunctional Self-Powered E-Skin with Tactile Sensing and Visual Warning for Detecting Robot Safety

Flexible electronic skins (e-skins) are widely applied in human activities monitoring, medical health, and robotic perception. However, most of the reported e-skins only focus on the physical force sensing. Herein, a novel multifunctional e-skin possessing physical force sensing and real-time visualization is proposed. The vertical-separation triboelectric sensor is used as the tactile sensing units, showing excellent performance with the open-circuit voltage (V₀) of 376.8 V, the short-circuit (I_s) of 1.02 µA, and the maximum output power density of 7.225 W m⁻², which also can carry out pressure detection with a wide detection range from 55.5 pa to 14 Kpa, a high sensitivity of 57.76 mV pa⁻¹, and a fast response time of 5.6 ms. The electrochromic devices as the visualization window shows the excellent stability and the low driving voltage. This e-skin can detect the instantaneous external force applied on the human arm and robotic arm and simultaneously shows the colors varying from light green to dark blue when experiencing the applied force. The proposed e-skin shows a promising solution of realizing both the digitized physical force sensing and the direct visualization, which can greatly enhance the safety precaution in various fields, such as robotic production line.