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A Light Touch

Photo of Curiosity on the surface of Mars

Curiosity on the surface of Mars in 2012. Research being conducted in the School of Physics could help design locomotion structures for future extraplanetary robot explorers.
Photo: NASA


Having a light touch can make a hefty difference in how well animals and robots move across challenging granular surfaces such as snow, sand, and leaf litter. New research shows how the design of appendages — legs or wheels — affects the ability of robots as well as animals to traverse weak and flowing surfaces.

Using an air-fluidized bed trackway filled with poppy seeds or glass spheres, researchers systematically varied the stiffness of the surface to mimic everything from hard-packed sand to powdery snow. By studying how running lizards, geckos, crabs — and a robot — moved through these surfaces, the researchers correlated variables such as appendage design with performance across the range of surfaces.

What the scientists learned from this study might help future robots avoid getting stuck in loose soil on some distant planet.

“You need to know systematically how ground properties affect your performance with wheel shape or leg shape, so you can rationally predict how well your robot will be able to move on the surfaces where you have to travel,” said Dan Goldman, a professor in Georgia Tech’s School of Physics.

Goldman compares the trackway to wind tunnels used for aerodynamic studies. “By varying the air flow, we can create ground that is very, very weak, so that you sink into it quite easily, like powdery snow, and we can have ground that is very strong, like sand,” he explained. “This gives us the ability to study the mechanism by which animals and robots either succeed or fail.”

Reported in the journal Bioinspiration & Biomimetics, the research was supported by National Science Foundation, Army Research Laboratory, and the Burroughs Wellcome Fund. 

— John Toon

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John Toon

John Toon

Director of Research News
Phone: 404.894.6986

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