Design and Fabrication of a Piezoresistive Tactile Sensor Inspired by Human Skin Microstructure for Robotic Manipulation

Tactile perception is indispensable for robots to manipulate objects dexterously. In the past decade, there has been a surge in reports on tactile sensors, and significant breakthroughs have been made, leading to the proposal of various high-performance tactile sensors. However, there exist high thresholds in terms of fabrication conditions, technological sophistication, and cost. In this study, a design and fabrication method for an easily producible tactile sensor is proposed, which mimics the structure of human skin, with the aim of providing robots with reliable and practical tactile sensing capabilities. By integrating$3\times 4$pairs of electrodes in an array pattern onto a$20\times 20$mm2 electrode board, an average spatial resolution of up to 4 mm was achieved. Further performance tests demonstrated a pressure sensitivity of 624 kPa$^{-{1}}$, a fast response speed of 9 ms, excellent durability that exceeds 2000 cycles, and the ability to effectively differentiate between contact points and types of stimuli such as normal force and shear force. The tactile sensory system integrated into the electric gripper at the end of the robotic arm can identify eight different objects with 98.0% accuracy across surface textures at a fixed sliding rate and achieves a 92.5% accuracy at random sliding rates. This sensory system is expected to assist robots in accomplishing more complex and dexterous tasks in the future through subtle tactile perception.