The simplicity but excellent mobility of snakes makes them an ideal creature for roboticists to emulate, but it also yields robots that are downright creepy. Making things worse, researchers at the University of California, Santa Barbara, and Georgia Tech, have made a snakebot that can burrow underground so we’ll never see it coming.
To date, we’ve managed to engineer robots and autonomous creatures that can handle almost any terrain, be it rolling across the rocky surface of Mars, diving below the waves, soaring through the sky, or even deftly tackling a flight of stairs. Where robots have yet to explore is underground. We’re not talking about spelunking through a cavernous subterranean cave, but instead burrowing and forging their own path through sand and soil like countless of Mother Nature’s creations do.
We’ve seen snakebots before, but the researchers at UCSB and Georgia Tech have created a new design with several key upgrades that allow it to more easily dig through granular materials all on its own. Unlike other snakebots, this version is what’s considered a soft body robot because, as the name implies, it forgoes rigid parts for flexible materials that make it lighter and more adaptable because it can more easily bend, twist, and contort its body.
One of the biggest challenges of burrowing through any material is the friction created, and having to overcome it. So the researchers took more inspiration from nature and copied the mechanism plants use to dig deep into the soil by growing only from the tip, leaving the rest of the root stationary. The snakebot does the same thing, growing only from the end of the bot so the rest of its body doesn’t actually move at all, eliminating a major source of friction. If you’ve ever struggled to pull a root out of the ground, it’s because you’re fighting against the friction of its entire length abrading against the surrounding soil.
The snakebot’s perpetually growing tip still requires a certain level of force to push sand and soil out of its way while it digs, but the research team once again found inspiration in nature to make this task easier for their bot. Like the southern sand octopus which shoots a jet of water into the ocean floor to loosen sand so it can bury itself as a protective defence mechanism, the snakebot fires a blast of air ahead of it to create a fluidised version of sand and soil that’s easier to push through.
By combining a wedged-shape ‘head’ with a blast of air directed slightly downwards, the snakebot loosens the soil ahead of, and below it, to reduce forces that naturally occur in granular materials that tend to push larger objects towards the surface. It not only makes it easier for the snakebot to dig, but it also makes it easier to remain underground as it burrows.
Besides giving the world one more source of anxiety, the burrowing snakebot does have some genuinely useful applications, and not just giving the militaries of the world an autonomous weapon that can burrow beneath walls, barbed wire, fields of land mines, and other obstacles.
While the rovers we’ve sent to Mars are equipped with drills, there’s far more to be learned about neighbouring planets by digging much deeper beneath their surfaces. It could even be a useful tool for archeology, letting scientists explore a site without having to disturb what’s on the surface until something needs to be unearthed.