Researchers develop advanced ‘human’ finger

Researchers at an American university have developed a new, advanced touch sensor for robots. The sensor should give robots a more or less human fingertip, which will enable them to recognize materials.

The University of Southern California researchers work in the Viterbi School of Engineering and developed there their BioTac sensor. Designed in the likeness of a human finger, the sensor is constructed around a solid-core liquid filling, covered by a flexible synthetic skin. The skin is provided with ridges, which should simulate a fingerprint, which should improve the recognition of textures and thus of materials.

The ridges make the ‘skin’ more sensitive to vibrations, which are picked up by a hydrophone within the fingertip. Different materials each produce their own vibrations, so that greater vibration sensitivity improves the recognition of materials. According to the researchers, their robot finger is more sensitive than a human finger and would correctly recognize the material presented in 95 percent of the cases. The robot was offered 117 different materials. Except for vibrations, the BioTac sensor also about heat and pressure sensors.

The software that enables the recognition and processes the sensor data uses an algorithm that analyzes and averages various movements and measured responses of the artificial finger. The researchers call the process ‘Bayesian exploration’, after an eighteenth-century mathematician who was responsible for a… rack for probability that is named after him. The BioTac sensor software uses a database of previous observations and bases the second and third finger movements on the results of the first measurement.

According to the researchers, their artificial finger and the associated software could play a role in the development of sensors for artificial hands. These could be used, among other things, in future prosthetics or for product assessments.