Growing robot with camera on tip

Growing robot demonstrates new form of robotic movement

Image credit: L.A. Cicero/Stanford news service

Researchers from Stanford University have created a long, soft robot capable of “growing” around obstacles. This could prove useful in search and rescue missions and medical devices.

Such a robot could extend itself through rubble to search for survivors after a natural disaster, rather than using sniffer dogs or diggers.

The robot is made up of an airtight tube of soft material folded in on itself “like an inside-out sock”. As the material at the front of the tube everts, the robot grows. This form of motion was inspired by plants and other organisms that reach outwards by growing, such as vines.

“The body lengthens as the material extends from the end, but the rest of the body doesn’t move,” said Professor Elliot Hawkes, a professor at the University of California, Santa Barbara, and lead author of the Science Robotics paper.

“The body can be stuck to the environment or jammed between rocks, but that doesn’t stop the robot because the tip can continue to progress as new material is added to the end.”

The team created a proof or concept of their robot using thin, cheap plastic inflated with air, and ran it through a series of tests. It was able to move through obstacles including flypaper, nails, and a wall of ice to deliver a carbon dioxide sensor. Despite being punctured by the nails, the robot completed the course, remaining speared on the nails while extending onwards to stay sealed.

In other demonstrations of its skills, the fragile-looking robot lifted a 100kg crate, slid under a door gap one-tenth its diameter, pulled a cable through its body, and spiralled on itself to form a free-standing structure to emit a radio signal.

Variations on the same robot include versions that could turn left or right in response to images collected by a camera at its front tip.

“The applications we’re focusing on are those where the robot moves through a difficult environment, where the features are unpredictable, and there are unknown spaces,” said Laura Blumnenschein, a graduate student and co-author of the paper. “If you can put a robot in these environments and it’s unaffected by the obstacles while it’s moving, you don’t need to worry about it getting damaged or stuck as it explored.”

The researchers are exploring how to make the robot suitable for real-world applications, possibly by using tough materials like Kevlar for its body, or creating much smaller versions to expand through the body without dragging along delicate structures to replace medical tubes. The robot be equipped with various sensors and transmitters, or be filled with fluid instead of pressurised air to deliver water to trapped people, or extinguish fires.

“Essentially, we’re trying to understand the fundamentals of this new approach to getting mobility or movement out of a mechanism,” said Professor Allison Okamura, a Stanford University engineer. “It’s very, very different from the way that animals or people get around the world.”

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