This is a robot that can grow to hundreds of times its size, and it can't be stopped by adhesives or spikes. Although it looks kind of simple and cheap, it has dozens of potential applications, including, one day maybe saving your life.

Now I made a video before about a soft truss robot. And this is also a soft robot, but very different in how it works and what it can do.

These robots can be made out of almost any material, but they all follow the same basic principle. Powered by compressed air, they grow from the tip.

(air hissing) (object rustling)

- That's good.

- And this allows the robot to pass through tight spaces, and also over sticky surfaces.

- Something like a car will get stuck to it. (car winding) It gets stuck in the wheels. Now, if I do the same thing with the vine robot, see the robot is able to extend...

- It can navigate this curvy and twisted passageway effortlessly, which suggests some of the applications it's well-suited for. Now you might think spikes would be the downfall of an inflatable robot, but even if it's punctured, as long as you have sufficient air pressure, the robot keeps going.

- And you might be able to hear it. (air hissing) It's actually leaking now, so I'll have to turn up the pressure. (object rustling) (air hissing) This by itself is not yet a robot, but once we add steering, a camera, some sensors, and maybe some intelligence as to where we're directing it, then we could say it's a robot. So this is sort of the backbone of our robot. This is what allows us to build our type of robots.

- So where did the idea for this device come from?

- I had a vine in my office that was on a shelf, and it was kind of out of the sunlight. And over the course of like a year or so, it slowly grew out this tender roll out and around the edge of the shelf and towards the sunlight. I said, "That's a pretty cool thing it just did," right? So I started thinking, "Well is there a way you can do that robotically?"

- The solution is really elegant in its simplicity. Just take some airtight tubing and fold it in on itself. It's kind of like a water wiggle, those toys that are really hard to hold. (air hissing) When you inflate it with compressed air, it starts growing out from the tip. And if you want the tube to always bend at a certain spot, you could just tape the tubing on the outside to shorten one of the sides. For example, you could tape it into a helical shape to create a deployable antenna. What about getting them to retract?

- Yeah, that's a challenging problem. When you're in a constrained environment, all you really have to do is pull on, we call it the tail, so the material that is passing through the core of the body, you pull on it and it basically ungrows, it just goes back inside itself. Now, if you're in a big open area like this, and you try pulling on that, instead of inverting, so retracting, it tends to kind of coil up and make a ugly shape.

- And the engineers have come up with ways to retract the tube to prevent it from buckling using internal rollers. But the two doesn't have to be the same diameter the whole way along, here there's actually a much wider section, think of it like a pillow that's packed into the end of the robot.

- Yeah, if you could sit cross-legged on it.

- Cross-legged on the table. This sounds (groans) super sketchy.

- So it grows underneath the table just as usual, and then as the pillow part starts inflating, (object clattering) (man mumbles) Is this not good, or is this okay? It can actually lift me up. So my balance is not great as we can see.

- You're standing on it.

- Stand on it?

- Yeah. What's amazing is that this doesn't require much pressure above atmospheric, just a 10th of an atmosphere applied over a large area like a square meter can lift something as heavy as 1000 kilograms, all the while remaining soft. (object rustling) Oh. Whoa, (sighs) that was great. That's the paradoxical thing about pressure. You can get a large overall force with low pressure as long as the area is large enough. What sort of area is that, that pillow there?

- It's 600 square inches. All right, so with one PSI it's 600 pounds.

- Yeah.

- Yeah. (laughs)

- Two PSI is 1200 pounds.

- That's just crazy. And the whole time it feels really soft.

- Yeah, 'cause there's a couple PSI, right?

- It's important that the device is still soft so it doesn't hurt anyone.

- So you can design these things to have cross-section that changes along its length. So it can be a very small body that could grow into, for example, a collapsed building and potentially lift a large object off someone who's trapped, or maybe in a car crash or something like that. It can apply huge forces with very soft (air whooshing) and lightweight cheap material.

- These robots can also be deployed in search and rescue operations by attaching sensors like a camera onto the front.

- These robots are actually really hard to stop. So you can take them, grow them into a clutter, potentially a class building or something like that, and they will continue to go somewhere. And alternative is they're so cheap, I mean, they're basically free. You could grow a hundred of them, let's say, into a collapsed building with some sensing on them, and maybe only one of them finds somebody. I mean, that's a huge success if it does.

- But how do you keep a camera connected to the front of the robot when it grows out from the tip? Well, one way is to use an end cap which allows that camera just to stay on the front, pushed from behind by the robot, but there are other mechanisms of attachment. The tiny wireless camera is mounted on an external frame, but this frame interlocks with an internal frame which is actually inside the pressurized part of the robot body. It's similar to how a roller coaster's wheels go around the track. So this prevents the camera from falling off as the robot grows. What's really interesting is how the vine robot can be actively steered. They attach artificial muscles to the robot. (air hissing)

- We don't actually use these much anymore because although it's soft, it's still somewhat stiff. So what we use instead are simply tubes of this ripstop nylon fabric with the braid oriented at 45 degrees. So in this sense we just have one single layer of airtight fabric. (air hissing) This is the main robot body here, then we have three pneumatic muscles connected to it. Now, these three muscles are each connected to their own air supply connected to regulators over here. As the robot extends from the tip, we can steer it by shortening and lengthening the sides. So, you know, just the way your hand works is if I shorten this tendon in my arm my hand will move this way, or if I shorten the one on this side it'll move the other way. So our vine robot, we have these muscles along its side, so as they inflate they'll turn it one way, then if I deflate the one on the other side, it'll turn the other way.

- So the vine robot can fit through tight spaces. It doesn't typically get stuck on anything and isn't bothered by sharp objects. And once you attach that camera on the front, it's ideal for things like archeology.

(group chattering) (objects clanking) The robot was actually taken to Peru to investigate some very narrow shafts.

- So we were looking at this archeological site that was built somewhere between 1500 and 500 BC in the Andes mountains of Peru, and it was an ancient temple that had all these underground spaces. And part of what the archeologists were doing was trying to understand what the spaces were for and what the people who built them were trying to do with them. So part of that was unknown, but there were these giant rooms that they called galleries, and then there were these small ducts or tunnels that were offshoots of these rooms, and they wanted to know where these ducts led but they were too small for a person to go in. So we were able to successfully use the vine robot to explore three of the tunnels that couldn't have been seen through other means, which was super exciting. And we got video inside the entire tunnels and gave it to the archeology team.

- There's an application where I feel like this solution is just so obvious I wonder why it didn't exist before.

- Intubation is literally the process of putting a tube into a patient. The purpose is to breathe for the patient when the patient isn't breathing. And so traditionally a highly trained medical professional would take their laryngoscope, come above the patient, and once they see the trachea, you start to pass your tube down inside. I'm almost there, I can see the light. So if you can see right now I just got it in to the trachea.

- Oh yeah.

- Right there. And it took me a couple of minutes and I was really kind of wrenching on this patient here as if there's somebody who's not breathing. Every second counts.

- But by using a miniature version of this vine robot, researchers are hoping to make intubation faster and safer.

- You know, somebody like me with no training could pretty simply insert this device aimed towards the nose and... (object squealing) just like that. If you can see, we've already intubated, and all it took was a little bit of pressurization. (man laughs) Just like that.

- It almost looks like sort of a party favor.

- Yeah, right. This reminds me a lot of those inflatable kind of like play-doh structures you see at car lots.

- How does it know to go down the right tube?

- Yeah, so that's one of the kind of cool things about soft robotics, is the robot is quite compliant. And we see that in a lot of these demos, you know, they can squish, they can bend. And so how we've designed it is that the main robot grows down into the esophagus, and then we have this side branch that heads towards the trachea, and it's quite flexible and so it basically finds the opening. So it's a really neat example of kind of a passive intelligence, mechanical intelligence some people call it, where it can find its path even if we don't know exactly the shape beforehand.

- Have you tried this on a real person yet?

- Not on a real person, but we've actually tried this in a cadaver lab. And we've shown that we can move from this nice idealized version to an actual in-vivo situation and successfully intubate a patient.

- There's another application which is burrowing into sand or soil. When you blow compressed air into something like sand, it fluidizes, it becomes like a liquid, and that can allow the vine robot to grow into granular materials like sand.

- If you've ever been to the beach and you try to stick like you umbrella pole into the ground, it's fairly difficult.

- And I'm trying to push that probe down into the sand, no fluid decision.

- Yeah, it feels like it sort of gets wedged in there.

- Let's now turn on the air. (air hissing)

- Oh yeah. You can feel it immediately. Oh, wow. Yeah, that's a lot.

- So what we've done here is essentially, we just blow a jet of air out the front of the robot and that loosens up the sand enough to reduce the force of the sand so that the robot just by tip extension can make its way through. (air hissing)

- This makes vine robots an attractive option for NASA when they look for ways to study the surfaces of other planets.

(machine roaring) Recently on Mars they tried to have a burrowing robot but it got stuck. Could you do it better basically with this?

- Yeah, that's a good question. So the Mars InSight mission, they have this heat probe, the idea there was to be able to sort of hammer its way down into the core, and then place a sensor that could detect the temperature of Mars. However, the problem they ran into there is that it turned out the material that they put it in was more cohesive than they expected. Inside the robot something would wind up and then pound it down, wind up and pound it down. But it turned out there wasn't enough friction between the probe and the sand. So what was really happening was it would wind up pound down, wind up pound down, wind up pound down. So it never actually got anywhere. The advantage of something like this, like tip extension, is you'd have your base, you start at the surface and you just keep extending your way down. You're not necessarily relying on the interaction with what is surrounding it to make it work.

- What amazes me about vine robots is how a plant inspired this simple, elegant design. It's so easy in fact that you could build one yourself in as little as a minute. There are instructions online that I'll link to. But from that basic design have come a huge variety of robots with different applications, from archeology to search and rescue, or intubation to space exploration. And what else can you think of to do with it?

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