Vertically agile robot developed by US researchers

The robotic design is based on the galago animal and can jump up to 1m

Researchers at University of California, Berkeley have designed a small robot that can leap into the air and then spring off a wall, or perform multiple vertical jumps in a row, resulting in the highest robotic vertical jumping agility ever recorded, according to the university.

To build the robot, known as Salto (saltatorial locomotion on terrain obstacles), the engineers studied the galago, a vertically agile animal that can jump five times in four seconds to gain a combined height of 8.5m.

Salto’s design is based on the power modulation used by the galago. Power modulation 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’s jumping ability comes from its tendons that are stored with energy by its muscles when it’s in a crouched position. Adapting this 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. By using power modulation, Salto doesn’t need to wind up before a jump. As soon as it jumps, Salto is ready to jump again.

To compare the vertical agility of robots and animals, 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 1.75m/s, which is higher than the vertical jumping agility of a bullfrog (1.71m/s), but short of the vertical jumping agility of the galago (2.24m/s).

Duncan Haldane, a robotics PhD candidate at UC Berkeley, said: “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.”

Salto achieved 78% of the vertical jumping agility of a galago. As a result of motor power limits, the best untethered robot before Salto had a vertical jumping agility of only 55% of a galago, according to the researchers.

Salto weighs 100g, is 26cm tall when fully extended, and can jump up to 1m. Salto’s maximum jump height was roughly 1.008m. For the wall jump, Salto attained an average height gain of approximately 1.21m.

The aim of the researchers is for the robot to be used to jump around rubble in search and rescue missions.

The work will be published in the journal Science Robotics.