These flexible feet help robots walk faster

An off-the-shelf six-legged robot equipped with the feet
designed by UC San Diego engineers can walk up to 40 percent faster
than when not equipped with the feet. Credit: University of
California San Diego

Roboticists at the University of California San Diego have
developed flexible feet that can help robots walk up to 40 percent
faster on uneven terrain such as pebbles and wood chips. The work
has applications for search-and-rescue missions as well as space

“Robots need to be able to walk fast and efficiently on natural,
uneven terrain so they can go everywhere humans can go, but maybe
shouldn’t,” said Emily Lathrop, the paper’s first author and a
Ph.D. student at the Jacobs School of Engineering at UC San

The researchers will present their findings at the RoboSoft
conference which takes place virtually May 15 to July 15, 2020.

“Usually, robots are only able to control motion at specific
joints,” said Michael T. Tolley, a professor in the Department of
Mechanical and Aerospace Engineering at UC San Diego and senior
author of the paper. “In this work, we showed that arobotthat can control the
stiffness, and hence the shape, of its feet outperforms
traditional designs and is able to adapt to a wide variety of

The feet are flexible spheres made from a latex membrane filled
with coffee grounds. Structures inspired by nature—such as
plant roots— and by man-made solutions— such as piles
driven into the ground to stabilize slopes— are embedded in
the coffee grounds.

The feet allow robots to walk faster and grip better because of
a mechanism called granular jamming that allows granular media, in
this case the coffee grounds, to go back and forth between behaving
like a solid and behaving like a liquid. When the feet hit the
ground, they firm up, conforming to the ground underneath and
providing solid footing. They then unjam and loosen up when
transitioning between steps. The support structures help the
flexible feet remain stiff while jammed.

It’s the first time that such feet have been tested on uneven
terrain, like gravel and wood chips.

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Originally published by
University of California – San
| June 1, 2020