Robotic finger outperforms humans in identifying natural materials

Developed by a team from the University of Southern California, the robot utilises a tactile sensor designed to mimic the human fingertip. It also features a newly designed algorithm that helps it make decisions about how to explore the outside world by imitating human strategies. Capable of other human sensations, the researchers say the sensor can tell where and in which direction forces are applied to the fingertip and even the thermal properties of an object being touched. Like the human finger, the BioTac sensor has a soft, flexible skin over a liquid filling. The skin even has fingerprints on its surface, greatly enhancing its sensitivity to vibration. As the finger slides over a textured surface, the skin vibrates in characteristic ways. These vibrations are detected by a hydrophone inside the bone-like core of the finger. While the human finger uses similar vibrations to identify textures, the robot finger is said to be even more sensitive. The researchers trained the robot on 117 common materials gathered from fabric and stationary shops. When confronted with one material at random, the robot was able to correctly identify the material 95% of the time after intelligently selecting and making an average of five exploratory movements. According to doctoral student Jeremy Fishel, who built the robot, it was only rarely confused by pairs of similar textures that human subjects making their own exploratory movements could not distinguish at all.