A robot that loves to walk in the grass

Scientists have invented a new robot that can easily walk on uneven terrain and on grass. They said the robot is the closest a machine has yet come to resembling human locomotion.

The researchers at the Oregon State University said the technology used in the two-legged robot heralds the running robots of the future.

The recent test demonstrated how their "ATRIAS" robot can move quite nicely, keep its balance and withstand mild blows from a bouncing rubber ball, while taking a walk in the grass, up and down hill, and over varying terrain at a normal walking speed of around five kmph.

"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," said Jonathan Hurst, director of the Dynamic Robotics Laboratory at OSU.

"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.

As a bipedal robot that was biologically inspired to mimic the spring-legged action of animals, the researchers said this is the closest a machine has yet come to resembling human locomotion.

The human-sized robot had six electric motors powered by a lithium polymer battery about the size of a half-gallon of milk, which is substantially smaller than the power packs of some other mobile robots.

This is made possible by the energy efficiency of its elastic leg design and the energy retention that's natural to animal movement.

"This will ultimately allow a much wider range of robotic uses and potential than something which requires larger amounts of energy," Hurst said.

"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.