Fabrication of inverse pyramid structured metal thin film-based tactile sensor for mimicking human sensory system

Abstract

The tactile sensor study, which simulates the human sensory organs, received a lot of attention in that it can detect human movement by attaching it to the electronic skin and can be applied to soft robotics to detect the surrounding environment. Among them, crack-based bending strain sensors are in high demand due to the advantage of being able to detect very fine vibrations or bending with high sensitivity. However, conventional bending sensors have difficulties due to the disadvantages of low detection range and low linearity to be used by being attached to actuators or human bodies. In this paper, a bending strain sensor was fabricated with a polydimethylsiloxane substrate having an inverted pyramid structure with regular intervals and sizes of hundreds of micrometers and a uniform platinum layer of tens of nanometers. The inverse pyramid structure of a certain arrangement induces the formation of uniform cracks and prevents propagation of cracks, allowing them to have high linearity (0.99) in a wide sensing range (> 5.5% bending strain). Also, the size and spacing of the inverse pyramids were adjusted to compare and optimize electrical characteristics. The manufactured sensor enables smart gloves applications and soft robotics applications based on a simple manufacturing process and high reliability.