Better-balanced robots

Researchers at Carnegie Mellon University’s Robotics Institute have designed a system that makes an off-the-shelf quadruped robot nimble enough to walk a narrow balance beam — a feat that is likely the first of its kind.

“This experiment was huge,” said Zachary Manchester, assistant professor at the institute and head of the Robotic Exploration Lab. “I don’t think anyone has ever successfully done balance beam walking with a robot before.”

By leveraging hardware often used to control satellites in space, he and his team offset existing constraints in the design of the quadruped to improve its balancing capabilities.

Researchers have designed a system that makes an off-the-shelf quadruped robot nimble enough to walk a narrow balance beam — a feat that is likely the first of its kind. Image courtesy of Carnegie Mellon University

The standard elements of most modern quadruped robots include a torso and four legs that each end in a rounded foot, allowing the robot to traverse basic, flat surfaces and even climb stairs. The design resembles a four-legged animal. But unlike cheetahs, which use their tails to control sharp turns, or falling cats, which adjust their orientations in midair with the help of their flexible spines, quadruped robots do not have such instinctive agility. As long as three feet of the robot remain in contact with the ground, the robot can avoid tipping over. But if only one or two feet are on the ground, the robot can’t correct easily for disturbances and has a much higher risk of falling. This lack of balance makes walking over rough terrain particularly difficult.

“With current control methods, a quadruped robot’s body and legs are decoupled and don’t speak to one another to coordinate their movements,” Manchester said. “So how can we improve their balance?”