Hybrid tactile sensor array for pressure sensing and tactile pattern recognition

Tactile sensor as core component of robotic haptics enables intelligent perception of external environment for smart robot. However, it is a critical challenge to realize simultaneously high-sensitivity pressure sensing and high-resolution tactile imaging of tactile sensor. Herein, a hierarchical hybrid tactile sensor array (HTSA), which is fabricated by vertically integrating top arrayed TENG layer and bottom arrayed capacitive pressure sensor layer, is developed to achieve simultaneous pressure sensing and tactile imaging for tactile pattern recognition. The capacitive pressure sensor array (8 × 8) can realize pressure sensing with a sensitivity of 238.73 kPa-1. Meanwhile, the TENG-based tactile sensing array enables high-resolution tactile imaging of handwritten Chinese characters. More importantly, the HTSA-based tactile pattern recognition system (H-TPRS) is developed to achieve accurate user signature authentication. Based on handwriting behavior characteristics, an accuracy of 97.3% of tactile pattern recognition is achieved in identifying the different-user handwriting identical letters under assistance of convolutional neural network. Consequently, the H-TPRS can achieve high-sensitivity pressure sensing and high-resolution tactile imaging of Chinese characters for user authentication, which demonstrates potential application in the field of intelligent tactile perception.