Tactile Sensor Array With Tertiary Leaf-Vein Structures and Position-Encoded Capacity

Abstract

Flexible tactile sensor is a preferred alternative in the development of human-machine interface (HMI) and robotics, which directly influences how we understand and interact with physical world. High density and high sensitivity tactile sensor array are urgently desired to assist people acquire tactile information of multi objects. However, although the existing researches exhibit great perception of tactile signals with different magnitudes and frequencies, they also expose limitation in the retrieval of relative position relationships. Herein, we report a wearable and high density (96 sensors on the fingertip) tactile sensor array based on tertiary leaf-vein inspired piezoresistive film. Particularly, a tertiary microstructure in the direction of height, including mid-vein-mimicking wrinkle (MVW), lateral-vein-mimicking wrinkles (LVW) and minor-vein-mimicking wrinkles (mVW), has been demonstrated an effective method to fabricate rough surface. The highly surface-controllable piezoresistive film dramatically enhances the durability (over 5000 cycles) and improves the sensitivity from 8.44 kPa <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> to 25.80 kPa <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> under 2 kPa. Accordingly, we propose an innovative position-encoded algorithm aimed at high density tactile sensor array, which has been demonstrated an excellent encode capacity of translating the multi-location tactile information caused by Braille characters into human-readable outputs. This study not only provides a map scanning method for Braille recognition, but also has significant implications for position-based information exchange or tactile encryption.