December 7, 2016

UC Berkeley researchers just developed the most agile robot ever

Engineers at the University of California Berkeley have developed a 3.5 ounce, 10-inch tall robot capable of leaping into the air and then springing off walls or executing numerous vertical jumps in a row.

According to a new study in the journal Science Robotics, the robot’s ability adds up to the highest robotic jumping agility ever achieved.

The study team said their robot's ability opens new possibilities of locomotion that had not been possible. They said this robot and others like it might be used to navigate rubble in search and rescue operations.

Finding Inspiration From Nature

To create the robot they dubbed Salto (Saltatorial locomotion on Terrain Obstacles), the engineers researched animals with fantastic jumping abilities. They focused specifically on the galago, a primate capable of jumping five times in four seconds to reach heights of close to 28 feet. The galago has a unique capacity to store energy in its tendons so that it can reach heights not possible by its muscles alone.

To contrast the jumping ability of robots and animals, the scientists created a new metric to evaluate vertical agility, described as the height that something can attain with a single jump in Earth gravity, multiplied by the rate at which that jump can be produced. Salto's robotic vertical jumping agility is 5.7 feet per second, which is greater than the vertical agility of a bullfrog (5.6 feet per second) but short of the vertical agility of the galago (7.3 feet per second).

Galago robot inspiration

The Galago served as a great point of inspiration for the team.

"Developing a metric to easily measure vertical agility was key to Salto's design because it allowed us to rank animals by their jumping agility and then identify a species for inspiration," team member Duncan Haldane, a Ph.D. candidate in robotics at UC Berkeley, said in a news release.

Salto's design is founded on the ability known as power modulation. Used by the galago, power modulation is an adaptation seen in natural systems that boosts the maximum power accessible for jumping by saving muscular energy in supple tendons.

The galago can make fantastic jumps because its tendons are loaded with energy when it's in a crouched posture. Adapting this method to Salto helped create its vertical ability. Inside Salto, a motor drives a spring, which loads via a leg system to generate the sort of crouch observed in the galago. Via power modulation, Salto doesn't have to wind up before a jump; once it jumps, Salto is preparing to jump again.

The UC Berkeley engineers noted that they were able to achieve 78 percent of the galago's jumping ability.

"By combining biologically inspired design principles with improved engineering technology, matching the agile performance of animals may not be that far off," said study author Ronald Fearing, a professor of electrical engineering and computer sciences at the California university.


Image credit: UC Berkeley/Stephen McNally