Suction is a useful tool in many robotic applications, as long as those applications are grasping objects that are suction-friendly—that is, objects that are impermeable and generally smooth-ish and flat-ish. If you can’t form a seal on a surface, your suction gripper is going to have a bad time, which is why you don’t often see suction systems working outside of an environment that’s at least semi-constrained. Warehouses? Yes. Kitchens? Maybe. The outdoors? Almost certainly not.

In general, getting robotic grippers (and robots themselves) to adhere to smooth surfaces and rough surfaces requires completely different technology. But researchers from Zhejiang University in China have come up with a new kind of suction gripper that can very efficiently handle surfaces like widely-spaced tile and even rough concrete, by augmenting the sealing system with a spinning vortex of water.

Suction climbing robotTo climb, the robot uses a micro-vacuum pump coupled to a rapidly rotating fan and a water source. Centripetal force causes the spinning water to form a ring around the outside of the vacuum chamber. Because water can get into all those surface irregularities that doom traditional vacuum grippers, the seal is much stronger.Image: Zhejiang University

The paper is a little bit dense, but from what I can make out, what’s going on is that you’ve got a traditional suction gripper with a vacuum pump, modified with a water injection system and a fan. The fan has nothing to do with creating or maintaining a vacuum—its job is to get the water spinning at up to 90 rotations per second. Centripetal force causes the spinning water to form a ring around the outside of the vacuum chamber, which keeps the water from being sucked out through the vacuum pump while also maintaining a liquid seal between the vacuum chamber and the surface. Because water can get into all of those annoying little nooks and crannies that can mean doom for traditional vacuum grippers, the seal is much better, resulting in far higher performance, especially on surfaces with high roughness.

Climbing robot with water vortex vacuum gripperOne of the potential applications for the water-vortex suction robot is as a “Spider-Man” wall-climbing device.Photo: Zhejiang University

For example, a single suction unit weighing 0.8 kg was able to generate a suction force of over 245 N on a rough surface using less than 400 W, while a traditional suction unit of the same footprint would need several thousand watts (and weigh dozens of kilograms) to generate a comparable amount of suction, since the rough surface would cause a significant amount of leakage (although not a loss of suction). At very high power, the efficiency does decrease a bit— the “Spider-Man” system weighs 3 kg per unit, with a suction force of 2000 N using 650 W.

And as for the downsides? Er, well, it does kind of leak all over the place, especially when disengaging. The “Spider-Man” version leaks over 2 liters per minute. It’s only water, but still. And since it leaks, it needs to be provided with a constant water supply, which limits its versatility. The researchers are working on ways of significantly reducing water consumption to make the system more independent, but personally, I feel like the splooshyness is part of the appeal.

Vacuum suction unit based on the zero pressure difference method,” by Kaige Shi and Xin Li from Zhejiang University in China, is published in Physics of Fluids.

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The Bionic-Hand Arms Race

The prosthetics industry is too focused on high-tech limbs that are complicated, costly, and often impractical

12 min read
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A photograph of a young woman with brown eyes and neck length hair dyed rose gold sits at a white table. In one hand she holds a carbon fiber robotic arm and hand. Her other arm ends near her elbow. Her short sleeve shirt has a pattern on it of illustrated hands.

The author, Britt Young, holding her Ottobock bebionic bionic arm.

Gabriela Hasbun. Makeup: Maria Nguyen for MAC cosmetics; Hair: Joan Laqui for Living Proof
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In Jules Verne’s 1865 novel From the Earth to the Moon, members of the fictitious Baltimore Gun Club, all disabled Civil War veterans, restlessly search for a new enemy to conquer. They had spent the war innovating new, deadlier weaponry. By the war’s end, with “not quite one arm between four persons, and exactly two legs between six,” these self-taught amputee-weaponsmiths decide to repurpose their skills toward a new projectile: a rocket ship.

The story of the Baltimore Gun Club propelling themselves to the moon is about the extraordinary masculine power of the veteran, who doesn’t simply “overcome” his disability; he derives power and ambition from it. Their “crutches, wooden legs, artificial arms, steel hooks, caoutchouc [rubber] jaws, silver craniums [and] platinum noses” don’t play leading roles in their personalities—they are merely tools on their bodies. These piecemeal men are unlikely crusaders of invention with an even more unlikely mission. And yet who better to design the next great leap in technology than men remade by technology themselves?

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