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For some reason, roboticists seem to enjoy testing their creations by kicking them, punching them, shoving them, 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].