Researchers at Oregon State University took their two-legged robot out for a field test last week, in an actual field. The ground selected was intentionally uneven, to see if the robot, named ATRIAS, would be able to keep its balance while walking about 3 miles per hour and being hit with a ball. It did. ATRIAS moved across changing terrain and went up and down slopes, with only a few fumbles.
While there are lots of robots that can walk on two legs, the researchers say the technology behind ATRIAS is worth noting because it most closely matches human locomotion. The specially designed elastic legs also retain energy, which decreases the power demands of the robot. This allows it to run on a lithium polymer battery about the size of a half gallon of milk. That’s smaller than some other mobile robots.
“Animals with legs sort of flow in the energy used, in which retained kinetic energy is just nudged by very efficient muscles and tendons to continue the movement once it has begun,” Jonathan Hurst, director of the Dynamic Robotics Laboratory in the OSU College of Engineering, said in a press release.
“That’s part of what’s unique about ATRIAS — not just that it can walk, and will eventually run — but that it’s doing so with animal-inspired fluidity of motion that is so efficient,” Hurst said. “This will ultimately allow a much wider range of robotic uses and potential than something which requires larger amounts of energy.”
The robot did fall a few times during testing due to sensor malfunctions, but fortunately it was was tethered to a safety harness on a massive supporting frame that was pushed by the researchers as the robot walked.
“It already appears that ATRIAS is three times more energy-efficient than any other human-sized bipedal robots,” said Christian Hubicki, an OSU postdoctoral scholar working with Hurst. “And this was the first time we’ve been able to show its abilities outside, in a far more challenging environment than anything in a laboratory.
“This is part of a continuous march toward running robots that are going to be useful and practical in the real world.”
ATRIAS was built in collaboration with Jessy Grizzle at the University of Michigan and Hartmut Geyer at Carnegie Mellon University, with funding from DARPA.