High-Sensitivity Capacitive Flexible Tactile Sensor Based on Hemispherical Shell Microstructure and ZnO/RTV Composite Dielectric Layer
Caixia Liu, Shuai Li, Qichang Sun, Fei Ma, Yifan Sun, Yugang Zhang, Lisha Xie, Ying Huang, Xiaoming Yang, Xingtong Hao
Abstract
The compressible microstructure-based tactile sensor with modified materials has garnered significant attention in recent years due to its distinctive structural characteristics, exceptional mechanical properties, and favorable dielectric properties. In this study, we present a capacitive pressure sensor featuring a hemispherical shell microstructure composed of a modified nano-ZnO/RTV (room temperature vulcanized silicone rubber) composite dielectric layer prepared through a simple and cost-effective inversion process. Incorporating titanate coupling agent-modified nano-ZnO into the silicone rubber dielectric layer with a semispherical shell structure significantly enhances both the mechanical and dielectric properties of the layer. As a result, the flexible capacitive sensor exhibits remarkable sensitivity (1.03 kPa –1 ), rapid response time (25 ms), an ultralow detection limit (1 Pa), and excellent stability over 10 000 usage cycles. Notably, these flexible devices can be utilized as wearable electronic skin for monitoring physiological stimulation and micropressure levels on human skin successfully. By integrating our high-sensitivity capacitive flexible tactile sensor with an innovative hemispherical shell microstructure dielectric layer onto the mechanical claw, we enable robots to discern object grasping quality through machine learning algorithms. The recognition accuracy rate exceeds 89%. Our research demonstrates promising prospects for applying this sensor in the field of robotic touch.