Watch Stanford’s Freaky New Soft Robot Grow Itself
The nineties were full of toys and consumer products that were, in hindsight, so bad it’s a wonder we as a society haven’t facepalmed ourselves to death yet. The road to marketing hell is paved with good intentions. One memorable toy from the collective childhood of my generation is the water wiggler — otherwise known as the water tube toy, water snake, or those weird squidgy jelly tube things. Remember these? Sometimes they had glitter in them, or tiny plastic fish. You’d try to hold them, and they’d slip right through your hands even though you had a secure grip on the outside.
Just phallic enough to make an adult vaguely uncomfortable, water wigglers were ubiquitous for a few years, and apparently now they’re inspiring robot design. Applied robotics researchers at Stanford have developed a soft-bodied robot that can turn itself inside out, and they hope to use it for disaster relief.
What makes the new techno-tentacle work so well is exactly that principle of turning itself inside out. It’s made of a long, double-walled plastic tube filled with pressurized air — topologically, it’s a torus, a donut. This gives it a unique advantage when it comes to pathfinding, which the new robot can do with eerie smoothness.
“The body lengthens as the material extends from the end but the rest of the body doesn’t move,” said 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.”
This friction-independent movement means that the robot can grow and pathfind like the end of a living vine, snaking its way over, around and through terrain with the greatest of ease. It lifted a 100kg crate, and then slipped through a gap only a tenth its own diameter. During its trials, the bot grew through the whole length of an obstacle course, where it navigated through flypaper, glue, nails and an ice wall to deliver a CO2 sensor payload, which could potentially sense the exhaled carbon dioxide produced by trapped survivors. It coiled into an upright spiral, which then broadcast a radio signal.
Most fantastical of all, the bot “successfully completed this course even though it was punctured by the nails, because the area that was punctured didn’t continue to move and, as a result, self-sealed by staying on top of the nail,” Stanford said in a statement.
Some prototypes were capable of differentially inflating the body of the bot, allowing its end to curl and turn. Others pulled a cable through the tube, which could point to a new way of laying down cables and wires.
The researchers also developed a software model that used image processing to determine where the bot should navigate, allowing it semi-autonomous control by way of that camera on the end. These exploits bring with them some really fun control problems, and because it all has to be done in real time, it’s ambitious. But the team is undaunted. They want to scale it both up and down, making larger and tougher models for disaster scenarios, or smaller and more delicate and dexterous versions for medical procedures like vascular surgery. And while the current prototypes have all been made of a thin, inexpensive plastic inflated with air, the soft bots could be made of things like ripstop nylon, or even Kevlar.
“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, 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.”