Robotic Hand With 3D Printed Fingertip

Artificial fingertips give robot hands human dexterity

Image credit: Prof. Nathan Lepora

An artificial fingertip imbued with the human sense of touch could allow robots to emulate high levels of dexterity.

Typically, robot hands lack dexterity because artificial grippers do not have the fine tactile sense of the human fingertip, which is used to guide our hands as we pick up and handle objects.

“Our work helps 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 could create robots that are more dexterous or significantly improve the performance of prosthetic hands by giving them an in-built sense of touch,” said Professor Lepora, a researcher from the University of Bristol.

The sense of touch in the artificial fingertip was created using a 3D-printed mesh of pin-like papillae on the underside of the skin, which mimics similar structures found between the layers of skin on a human finger. The papillae are made on advanced 3D printers that can mix soft and hard materials to create complicated structures like those found in biology.

“We found our 3D-printed tactile fingertip can produce artificial nerve signals that look like recordings from real, tactile neurons. Human tactile nerves transmit signals from various nerve endings called mechanoreceptors, which can signal the pressure and shape of a contact,” Lepora added.

“Classic work by Phillips and Johnson in 1981 first plotted electrical recordings from these nerves to study ‘tactile spatial resolution’ using a set of standard ridged shapes used by psychologists. In our work, we tested our 3D-printed artificial fingertip as it ‘felt’ those same ridged shapes and discovered a startlingly close match to the neural data.”

While the research found a remarkably close match between the artificial fingertip and human nerve signals, it was not as sensitive to fine detail.

The researchers suspect this is because the 3D-printed skin is thicker than real skin, and the 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 as – or even better than – real skin,” said Professor Lepora.

In 2019, a recycling robot was unveiled that uses sensors in its hand to determine the nature of a waste item and sort it accordingly.

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