The math that went into this robot could improve planetary rovers in the future, researchers say.
By Francie Diep Posted 03.22.2013 at 11:00 am 8 Comments

Sand Strider
Sand Strider This little legged robot moves especially efficiently on grainy media, such as sand. Image courtesy of Chen Li, Tingnan Zhang, Daniel Goodman

Is this what the Mars rovers of the future might look like?

Physicists at the Georgia Institute of Technology have tackled an unusual robot problem: How to walk across sand. There are plenty of mathematical models for how animals and machines move through air and water and over solid ground, the team wrote in a paper they published today in the journal Science. But, they wrote, research is just starting on the math of walking through sand, gravel, or any other "naturally occurring granular media of high sphericity and roundness."

Considering that sand is pretty common on Earth and other planets, the researchers decided to try to create better equations for beachside locomotion. They both built little legged robots and wrote the equations that describe the interactions between the robots' legs and different grainy media, including poppy seeds, tiny glass beads and actual sand from the outdoors. The equations could help others improve walking robots and planetary rovers, California Institute of Technology engineer Melany Hunt wrote in an essay in Science.

They also found the most efficient legs for sand-walking bots are C-shaped, with the curve of the C facing forward. The legs are a departure from the tracks that military tanks, construction equipment and other gravel-navigating vehicles have. Tracks have not worked as well as expected for smaller machines, such as Mars rovers, the Georgia Tech physicists wrote. Smaller vehicles' wheels end up curving the track substantially, reducing the tracks' performance.

Check out the C-legged robot scuttling its way across sand. Video courtesy of Chen Li, Tingnan Zhang and Daniel Goldman.

8 Comments

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Amun-Ra
03/22/13 at 11:07 am

Everything electronic and mechanical is a robot now a days, especially if it help it to sale!

LoL, yes a washing machine is a robot too, oye..... snort.

..........................

Interesting gadget in the artricle! Well done!

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Mister Thomas
03/22/13 at 11:18 am

Interesting to see the little feller running in the sandbox at full speed. But how about just walking in the sand.

Also - can't see the essay. Can you fix the link?

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oldbill70
03/22/13 at 12:12 pm

I'm no scientist but tracks have been treading sand, mud and other unfriendly media for a lot of years. I maintain that a properly designed track, meaning well supported, will outperform any of these new-fangled gadgets. I've driven a lot of tracked vehicles and never got one stuck so bad it couldn't get out by itself. Can this robot go backwards? Tracks go either direction equally well and they're not too hard to turn if you know what you're doing.

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KF159
03/22/13 at 1:51 pm

It looks like this thing cannot go backwards. Because of the shape of it's legs it would just start digging.

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david_forbus
03/22/13 at 2:25 pm

Those are not legs. It's a variation of the wheel. I'm sure the excessive vibration caused by this type of motion will prove to be problematic.

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whitephatt
03/22/13 at 3:09 pm

Oh lawdy lawd.. What came first? The RHex Rough-Terrain Robot built by Boston Dynamics (google it for videos) or this 'Sand Strider' built by a bunch of durpy college students?

I know where I'd place my bet...

www.youtube.com/watch?v=ISznqY3kESI&feature=share&list=UU7vVhkEfw4nOGp8TyDk7RcQ

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fcdiep
03/23/13 at 4:45 pm

Mister Thomas, I fixed the link. Thanks for the heads up!

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Antadros
03/23/13 at 11:49 pm

It seems this variant of the Rhex robot does a good Jon but fails in the big haul often times getting dug in before reaching the end. It seems that the two back 'legs' get dug in first and thusly, I believe that increasing the overall surface area of the back legs and/or slowing them down. However, I don't know what that would do to the overall locomotion.


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