Touching Subject: 3D Printed Fingertip ‘Feels’ Like Human Skin

The highly sensitive, 3D-printed fingerprint could help robots become more dexterous and improve the performance of prosthetic hands, giving them an inherent sense of touch.

Machines can beat the best chess player in the world, but they can’t handle a chess piece as well as a baby. This lack of robotic dexterity is partly because prosthetic grippers lack the subtle tactile sense of human fingers, which are used to guide our hands as we lift and handle objects.

Robotic hand with 3D-printed tactile fingers on the little (pinky) finger. The hard white part up to the tip of the fingers is covered with a flexible 3D-printed black skin. Image credit: University of Bristol

Two papers published in the Journal of the Royal Society Interface compare the depth-first of prosthetic fingers with neural recordings of the human sense of touch. The research was led by Nathan Lepora, Professor of Robotics and AI (artificial intelligence) based at the University of Bristol’s Department of Engineering Mathematics and the Bristol Robotics Laboratory.

“Our work helps to uncover how the complex internal structure of human skin creates our human sense of touch. This is an exciting development in the field of soft robotics – being able to 3D-print tactile skin makes such robots can that are more efficient or significantly improve the performance of prosthetic hands, giving them an inherent sense of touch,” said Professor Lepora.

Cut-through section on 3D-printed tactile skin. The white plastic is a rigid mount for the flexible black rubber skin. Both parts are made together on an advanced 3D-printer. The ‘pins’ inside the skin mimic the dermal papillae that form inside human skin.

Professor Lepora and his colleagues created a sense of touch in prosthetic fingers using a 3D-printed mesh of pin-like papillae under the compliant skin, which are the dermal papillae found between the outer epidermal and inner dermal layers of human tactile skin. Let’s copy. , The papillae are made on advanced 3D printers that can blend soft and hard materials together to form the complex structures found in biology.

“We found that our 3D-printed tactile fingers can produce artificial nerve signals that look a lot like recordings from real, tactile neurons. Human tactile nerves transmit signals from various nerve endings called mechanoreceptors, which act as contacts. In 1981, the classic work of Phillips and Johnson used a set of standard streak shapes used by psychologists to study ‘tactile spatial resolution’ for the first time from these nerves. In our work, we tested our 3D-printed prosthetic finger as it ‘feeled’ the same ridged shapes and found a startlingly close match with the neural data,” said Professor Lepora.

“For me, the most exciting moment was when we looked at our artificial nerve recordings from 3D-printed fingers and they looked like real recordings from 40 years ago! Those recordings are so complex, with hills and edges and ridges, And we saw similar patterns in our artificial touch data,” said Professor Lepora.

While the research found a remarkably close match between prosthetic fingers and human nerve signals, it was not as sensitive to fine detail. Professor Lepora suspects this is because 3D-printed skin is thicker than real skin and his team is now exploring how to 3D-print structures on the microscopic scale of human skin.

“Our aim is to make artificial skin as good – or even better – than real skin,” Professor Lepora said.

Source: University of Bristol

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