A bipedal robot can now put its best foot forward, stepping with a
heel-toe motion that copies human locomotion more closely than
flat-footed robot walkers can.
By rocking its "feet" forward from the heel and pushing off at the toe,
the DURUS robot closely imitates the walking motion of people, making
it more energy-efficient and better at navigating uneven terrain,
according to Christian Hubicki, a postdoctoral fellow in robotics at the
Georgia Institute of Technology and one of the researchers who helped
DURUS find its footing.
Enhanced walking capabilities could help robots navigate environments
that people move around in, and could improve the performance of bots
created for disaster response, Hubicki told Live Science.
The humanoid robot DURUS was designed collaboratively by the research
nonprofit SRI International and Georgia Tech's Advanced Mechanical
Bipedal Experimental Robotics (AMBER) Lab. An earlier DURUS design was
modified to accommodate the new manner of walking, enabled by a novel
mathematical algorithm that adjusts the robot's momentum and balance,
one step at a time.
Well-heeled
Robots that walk on two legs typically have "feet" that are large and flat, to provide a more stable platform, Hubicki told Live Science.
"Bigger feet mean a bigger polygon of support, and the harder it is to fall," Hubicki said.
The algorithms that dictate a robot's forward momentum typically keep
those big feet flat on the ground when pushing off, to minimize the risk
that the bot will tip over.
"As soon as you lean on an edge, you're like a pendulum — on a pivot point that can fall forward or backward," Hubicki said.
But while a flat-footed walker might perform well on a treadmill, uneven terrain in the real world that doesn't accommodate a flat foot could confound the algorithm and stop a robot in its tracks.
Enter the AMBER Lab researchers, who designed a new algorithm that works to keep a robot upright and moving forward even
if only parts of the foot are engaged. Hubicki and his colleagues
tested DURUS using a modified foot with an arch; every step began with
the heel making contact — the "heel strike," according to Hubicki — and
then rolling to the ball of the foot to push off from the ground.
Springs installed by the robot's ankles act like tendons, storing the
heel strike's energy to be released later, as lift.
On July 12, AMBER Lab posted a video of a confidently striding DURUS on YouTube.
DURUS' new feet are about the same size as human feet — about half as
long as the feet on the original model. And to emphasize the similarity,
the team laced them into a pair of sneakers.
"We wanted to show that our algorithms could make it walk with
human-size feet," Hubicki said. "What better way to do that than [by]
putting shoes on it?"
The algorithm may even have applications beyond robotics, Hubicki
added, suggesting that it could be used to improve the design of
prosthetics and exoskeletons to help people who use assistance to get around.
so funny....
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