The four-legged robot, dubbed Cheetah and developed by Boston Dynamics on behalf of the Defense Advanced Research Projects Agency, set a speed record of 28.3 miles per hour over 20 meters. Bolt, who won three gold medals in the 2012 Olympics in London, set a human record in 2009 with a top speed of 27.78 mph for 20 meters during a 100-meter sprint.
Cheetah did have an advantage, as its record-setting performance was done on a treadmill. That was comparable to running with a tail wind, since most of the robot's effort was used to lift and swing its legs fast enough to keep pace, not to propel it.
The robot had already claimed the world record for legged robots in March, when it ran 18 mph on the treadmill. The previous record of 13.1 mph was set in 1989.
Cheetah is powered by an outside hydraulic pump, and a boom-like arm keeps it centered on the treadmill. The 57% speed gain came from improved control algorithms and a more powerful pump.
Cheetah was developed as part of DARPA's Maximum Mobility and Manipulation (M3) program. Legged robots would be useful in rough terrain because they can step over obstacles or ditches. Yet, because it's difficult to coordinate leg movement, legged robots have sacrificed speed for balance and mobility.
Cheetah's movements are based on the way fast animals run in nature, by flexing and straightening its back on each step, for example. DARPA is attempting to build robots with "core capabilities that living organisms have refined over millennia of evolution: efficient locomotion, manipulation of objects, and adaptability to environments," said M3 program manager Gill Pratt in a statement on Cheetah's achievement.
Cheetah "borrows ideas from nature's design" in its stride patterns, flexing and unflexing of parts, placement of limbs, and stability, Pratt said.