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Japanese Humanoid Robot Can Keep Its Balance After Getting Kicked

University of Tokyo researchers used kicks, knee strikes, and shoves to test their new robotic legs

2 min read
Japanese Humanoid Robot Can Keep Its Balance After Getting Kicked

HRP3L-JSK Japanese humanoid robot getting kicked

For some reason, roboticists seem to enjoy testing their creations by kicking them, punching them, shovingthem, and even striking them with baseball bats and heavy pendulums. All in the name of science, of course. It wasn't different with this Japanese pair of robot legs, which as you can see from the photo above, is about to get kicked in the gut.

If we want robots that can do chores around the house, care for the elderly, or (if you're a DARPA program manager) drive trucks and crash through walls, then we need robots with actuators that are both fast and strong. The problem is actuators based on electrical motors can only deliver a limited amount of power, and the alternative, hydraulics, requires bulky pumps and can be difficult to control.

Junichi Urata and his colleagues at the University of Tokyo's JSK Lab, led by Professor Masayuki Inaba, are working on a possible solution. They've developed a high-torque, high-speed robotic leg based on a novel electrical actuation system. Their robot uses high-voltage and high-current liquid-cooled motor drivers that get their power from a 13.5-farad capacitor system. Why a capacitor? Because it can supply lots of current very fast and reliably, something that batteries are not good at. The researchers modified an existing HRP3L, developed by Kawada Industries, to create their robot, which they call HRP3L-JSK [pictured below].

Thanks to the capacitor-powered motor drivers, the robot's Maxon 200-watt brushless motors (modified to be liquid-cooled) can achieve instantaneous speeds of over 1000 degrees per second and 350 Nm of torque on the robot's knee joint. This capability allows the 53-kg robot to react to disturbances (in its case, kicks, knee strikes, and other abuse from researchers) and even jump 44 centimeters off the ground (though the landing part will need work). Watch:

The robot relies on a new balance control system that detects disturbances and computes 170 foot placement possibilities in 1 millisecond, choosing the best candidate to keep the robot from falling. The new method is a collaboration between the JSK team and researchers from Japan's National Institute of Advanced Industrial Science and Technology (AIST).

Urata, who recently received a PhD degree for his HRP3L-JSK work, now has his eyes on the DARPA Robotics Challenge. He's starting to organize a team to add manipulation arms and more sensors to the HRP3L-JSK lower-body. Will their fully electrical robot be able to perform all the tasks DARPA has conceived for the challenge? DARPA, for its part, has chosen a Boston Dynamics humanoid powered by hydraulic systems as the official hardware platform (to be used by teams that don't want, or can't afford, to develop their own robot). As more teams join the competition, it will be interesting to see what kind of actuation system they choose. Electrical or hydraulics: which will prevail?

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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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