Anyone Can Be Spider-Man With DARPA's Wall-Climbing Invention: VIDEO

Anyone Can Be Spider-Man With DARPA's Wall-Climbing Invention

The U.S. military's amazing new inventions allow soldiers to climb walls made of nearly any material, without the need for ropes or ladders.

I'm dangling near the top of a twenty-foot plate of glass. All two hundred pounds of me. On land, I can't do a single pull-up—not even if you held a doughnut over the bar. But I got up here using my own strength, and if it weren't for my nerves, I wouldn't have broken a sweat. The suction-cup paddles in each of my hands are harnessed to my waist. Stirrups loop around my feet. As I shift my weight off my right leg and onto my left, the pneumatic fingers on the paddle in my right hand release the pressure holding the seven suction cups above them to the wall. My body weight moves to my left leg, pulling down the fingers in the paddle in my left hand. The suction cups of the left paddle push into the wall, forcing microscopic silicone ridges against the glass for maximum surface contact and hold. When I reach the ceiling, I linger, feeling more than a little like a superhero, but also wondering how I'm going to get down.

Those loops around my feet are very important. If I lean too far back or to the side—the vector of my weight no longer directly beneath the paddle—that suction will quickly release. I know this because it's exactly what I do. In my excitement to move from the glass wall and try the device on a painted surface, I stretch the paddles too far apart. With my foot and my weight no longer aligned below the paddles, I slide down the wall and crash to the ground in a tangle of devices and—luckily—backup ropes.

The idea for this equipment—called Z-Man, named for the third-dimensional, or Z axis—came about ten years ago at DARPA, a group whose mission is to protect the defense establishment and the nation from technological surprise. Two program managers, John Main and Morley Stone, were discussing the urban battlefield. "We were in the thick of the Iraq war and a lot of activities taking place were urban, and the urban high ground is the top of buildings," says Main. "We were trying to get people safely to the top of a building." A study at Stanford suggested that mimicking gecko skin could help small robots climb, and Stone and Main wondered if the same type of technology would work for humans. "Stone shrugged his shoulders and said, 'I think so,' " Main says. "And I shrugged my shoulders and said, 'I think so.' That was the genesis of the whole program."

For the past decade, DARPA Z-Man scientists have struggled with a challenge that has perplexed scientists since Aristotle: How the hell does a gecko run up and down a tree? And how do we replicate that ability on humans? There were many theories and, in desperate times, the suggestion of magic. But "it's nothing like magic," Main says. "If you look at the toe of a gecko, it's got millions and millions of tiny 'hairs.' These little protrusions are very flexible and very, very strong. The gecko gets all of those hairs in very close contact with the wall he's climbing or the ceiling he's hanging from, and they all hold him up." The phenomenon is based on a physics principle called van der Waals forces, in which atoms in very close contact create a temporary attraction. So they understood how the sticking-to-the-wall part happened. Next they had to figure out the actual movement—to translate the mechanics of how the gecko dragged its upper and lower feet together to maintain the van der Waals attraction, while also being able to move freely. Even when upside down.

Things got frustrating. Whatever the scientists learned, whatever new approaches they took, the results didn't seem applicable to human use. "This program would have been over in two years if we could have done exactly what the gecko does," Main says. "But what the gecko does that humans can't do is flex between two contact points all the time. People can't get their hand on the wall and their foot on the wall, and put a lot of force into sliding them toward each other." Plus, there are all types of walls. What works on glass may not work on brick, which may not work on metal.

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