Robot can outperform humans in identifying natural materials

Researchers in the US have developed a robot that can touch and identify more than 100 common materials.

According to a statement, a team at the University of Southern California’s Viterbi School of Engineering has published a study showing that a specially designed robot can outperform humans in identifying a wide range of natural materials according to their textures. The study could help advance prostheses, personal assistive robots and consumer product testing.

The robot was equipped with a new type of tactile sensor built to mimic the human fingertip. It also used a newly designed algorithm to make decisions about how to explore the outside world by imitating human strategies.

The sensor also has the ability to 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 group’s BioTac sensor has a soft, flexible skin over a liquid filling. The skin even has fingerprints on its surface that greatly enhance its sensitivity to vibration.

As the finger slides over a textured surface, the skin vibrates in characteristic ways and the vibrations are detected by a hydrophone inside the bone-like core of the finger. The human finger uses similar vibrations to identify textures, but the robot finger is said to be even more sensitive.

Built by Jeremy Fishel, a recently graduated doctoral student, the robot was trained on 117 common materials gathered from fabric, stationery and hardware stores. When confronted with one material at random, the robot could correctly identify the material 95 per cent of the time, after intelligently selecting and making an average of five exploratory movements. It was only rarely confused by pairs of similar textures that human subjects making their own exploratory movements could not distinguish at all.

Fishel and co-author Prof Gerald Loeb believe this robot touch technology could be used in human prostheses or to assist companies that employ experts to assess the feel of consumer products and even human skin.

Loeb and Fishel are partners in SynTouch, which develops and manufactures tactile sensors for mechatronic systems that mimic the human hand. Founded in 2008 by researchers from the University of Southern California’s Medical Device Development Facility, the start-up is now selling the BioTac sensors to other researchers and manufacturers of industrial robots and prosthetic hands.