Vine-like robot grows long distances without moving its whole body
20 July 2017
Inspired by natural organisms that cover distance by growing, researchers have developed a soft, growing robot and put it through its paces.
The robot is a tube of soft material folded inside itself, like an inside-out sock, that grows in one direction when the material at the front of the tube everts, as the tube becomes right-side-out.
The Stanford University researchers created prototypes to move through various obstacles, travel toward a designated goal and grow into a free-standing structure. The prototypes were made from thin, cheap plastic and the robot body everted when the researchers pumped pressurised air into the stationary end. In future versions, the air could be replaced with liquid, which could help deliver water to people trapped in tight spaces or put out a fire in a closed room. New, tougher materials could also be used, like rip-stop nylon and Kevlar.
The researchers say, what makes this design useful is it results in movement of the tip without movement of the body. “The body lengthens as the material extends from the end but the rest of the body doesn’t move,” explained Elliot Hawkes, a visiting assistant professor from the University of California, Santa Barbara and lead author of the 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 robot could be useful for search and rescue missions or medical devices. In one application example, the robot lifted a 100kg crate and grew under a door gap that was 10 percent of its diameter.
“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 Blumenschein, a graduate student in the Okamura lab 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 explores.”
Some iterations of these robots included a control system that differentially inflated the body, which made the robot turn right or left. The researchers developed a software system that based direction decisions on images coming in from a camera at the tip of the robot.
The researchers hope to scale the robot much larger and much smaller to see how it performs. They’ve already created a 1.8mm version and believe small growing robots could advance medical procedures. In place of a tube that is pushed through the body, this type of soft robot would grow without dragging along delicate structures.
Video courtesy of Stanford