Piano-playing 3D printed robotic hand spreads holiday cheer

Forget the classic crooners and pop classics, there’s a new Christmas music star in town! Researchers from the University of Cambridge have created a 3D printed robotic hand that can play Jingle Bells and other simple tunes on the piano.

The research team itself admits that the robotic hand is no musical prodigy as its motions are more limited than a real human hand—so I might wait before tossing out all your favourite holiday albums. But still, the project is a promising start to an exploration into and replication of human movement.

The hand was developed using a combination of soft and rigid materials, 3D printed to replicate all the bones and ligaments in a human hand. Even without the integration of replicated muscles and tendons, the researchers were interested to find that the robotic hand was still capable of many types of movement, albeit passive movement.

Presently, the 3D printed robotic hand is not capable of moving its fingers independently, but the researchers were still able to program it to play the piano using various rudimentary techniques. Evidently, piano playing is not the researchers’ end goal with the project, but it is a good way to explore the complex movements of the human hand. The ultimate aim of the project is to find new, more intelligent methods to mechanically design robots that are capable of more natural movements with minimal energy use.

“We can use passivity to achieve a wide range of movement in robots: walking, swimming or flying, for example,” explained Josie Hughes from Cambridge’s Department of Engineering and first author of the study. “Smart mechanical design enables us to achieve the maximum range of movement with minimal control costs: we wanted to see just how much movement we could get with mechanics alone.”

“The basic motivation of this project is to understand embodied intelligence, that is, the intelligence in our mechanical body,” added Dr Fumiya Iida, who led the research project. “Our bodies consist of smart mechanical designs such as bones, ligaments, and skins that help us behave intelligently even without active brain-led control. By using the state-of-the-art 3D printing technology to print human-like soft hands, we are now able to explore the importance of physical designs, in isolation from active control, which is impossible to do with human piano players as the brain cannot be ‘switched off’ like our robot.”

Piano playing, as it turns out, was a suitable way to play with and test these passive systems because of the different types of movement behaviour it necessitates. In programming the 3D printed hand to play the piano, the researchers had to take into account various elements, such as mechanics, material properties, environment and wrist actuation.

By actuating the wrist, the researchers explain, it was possible to control how the hand interacts with the piano, enabling the hand’s embodied intelligence to “determine how it interacts with the environment.” Using this method, the research team programmed the robotic hand to play musical phrases using either staccato or legato notes.

“It’s just the basics at this point, but even with this single movement, we can still get quite complex and nuanced behaviour,” Hughes said.

Down the line, the Cambridge-based research initiative could have implications for the way that robots and mechanical structures are designed. As Hughes added: “We can extend this research to investigate how we can achieve even more complex manipulation tasks: developing robots which can perform medical procedures or handle fragile objects, for instance. This approach also reduces the amount of machine learning required to control the hand; by developing mechanical systems with intelligence built in, it makes control much easier for robots to learn.”