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SAN FRANCISCO, Dec. 10 (Xinhua) -- Engineers at the University of California, Berkeley, have built a small robot capable of leaping into the air and then springing off a wall, or performing multiple vertical jumps in a row, resulting in the highest robotic vertical jumping agility ever recorded.
The robot, known as Salto, short for saltatorial locomotion on terrain obstacles, weighs 3.5 ounces, or 100 grams; is 10.2 inches, or 26 centimeters, tall when fully extended, and can jump up to one meter. For the wall jump, Salto attained an average height gain of about 3.97 ft, or 1.21 meters.
The researchers developed a new metric to measure vertical agility, defined as the height that something can reach with a single jump in Earth gravity, multiplied by the frequency at which that jump can be made.
Salto's robotic vertical jumping agility is 1.75 meters per second, which is higher than the vertical jumping agility of a bullfrog (1.71 meters per second) but short of the vertical jumping agility of the galago (2.24 meters per second).
"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," said Duncan Haldane, a robotics Ph.D. candidate at UC Berkeley, who led the work published in the debut edition of the journal Science Robotics.
Salto's design is based on the galago's power modulation, which is an adaptation found in natural systems and designed into some robotic systems that increases the peak power available for jumping by storing muscular energy in stretchy tendons.
The galago jumps so well because its tendons are loaded with energy by its muscles when it's in a crouched position. Adapting the process to Salto enabled its high vertical agility, including the wall jump.
Inside Salto, a motor drives a spring, which loads via a leg mechanism to create the kind of crouch seen in the galago. Salto doesn't need to wind up before a jump; as soon as it jumps, it is ready to jump again. It achieved 78 percent of the vertical jumping agility of a galago.
Because of motor power limits, the best untethered robot before Salto had a vertical jumping agility of only 55 percent of a galago.
"By combining biologically inspired design principles with improved engineering technology, matching the agile performance of animals may not be that far off," Ronald Fearing, a professor of electrical engineering and computer sciences who heads the Biomimetic Millisystems Lab, where Haldane is a student, was quoted saying by a news release from UC Berkeley in northern California on the U.S. west coast.
