3D Printing Creates Tactile Artificial Fingers Resembled to Real Human Fingers

A team of researchers from the University of Bristol’s Robotics Laboratory has recently published two papers in the Journal of the Royal Society Interface, which compared the artificial nerve signals produced by 3D-printed tactile fingertips with the tactile neural signals of real human beings for the first time. An in-depth comparison of the two signal patterns revealed that they are very similar, which would increase human applications of future robots and optimize the dexterity development of prostheses.

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Creating Tactile 3D Printed Artificial Fingertips by Mimicking the Inner Structure of Skin

To unravel the complex structure of human skin to understand how tactile sensations are generated and created, the research team led by Professor Nathan Lepora, 

Professor of Robotics and Artificial Intelligence from the University of Bristol’s Department of Engineering Mathematics used 3D technology to print a mixture of hard and soft materials to mimic the complex papilla-like structures between the outer epidermis and inner dermis to create an artificial fingertip with tactile sensations.

The team first studied how signals are transmitted to and received by the human tactile nerves, then coded the signals and used a 3D printed bionic tactile sensor (TacTip) to create two artificial tactile nerves, SA-I and RA-I, and an embedded sensor to receive vibration signals, RA-II. Spatial tactile responses are generated by the interaction of signals transmitted by the three artificial nerves.

Signals Received by Artificial Fingers Closely Resemble Those of the Real Human Body

Mechanoreceptors in the human skin receive signals from various tactile nerve terminals and sense shapes through signals generated by different touch pressures. In 1981, neuroscientists J.R. Phillips and K.O. Johnson made the first graphical record of the electrical signals generated by these tactile nerves in spinal structures to investigate the “tactile spatial resolution”.

The team found that the 3D-printed artificial fingertips “felt” the artificial nerve signals generated by the same spinal structures in a very similar way to the record of electrical signals sensed by real human tactile neurons four decades ago. Despite the complexity of the electrical signals recorded, which included various irregular crests and troughs, similar patterns were observed in the artificial tactile data, suggesting that the artificial fingertip can mimic the sensory ability of human touch.

However, the artificial fingertips are still not sensitive enough to the details of objects. The team believes that this may be due to the fact that the 3D-printed skin is thicker than real skin. For this reason, they will continue to study how to optimize the ability of sensing artificial tactile sensations by printing human skin at a microscopic scale. “Our aim is to make artificial skin as good – or even better – than real skin,” said Professor Lepora.

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GeneOnline Team