Robojelly gets an upgrade

Nov 22, 2011
Robojelly gets an upgrade

Engineers at Virginia Polytechnic Institute and State University (VirginiaTech) have developed a robot that mimics the graceful motions of jellyfish so precisely that it has been named Robojelly. Developed for the Office of Naval Research in 2009, this vehicle was designed to conduct ocean underwater surveillance, enabling it potentially to detect chemical spills, monitor the presence of ships and submarines, and observe the migration of schools of fish.

Recently, a team at VirginiaTech has improved the performance of this silicone swimmer, enabling it to better overcome the limitations of its and better mimic the true motion of a jellyfish. Details on this new design and how it might provide new insights into jellyfish propulsion mechanisms will be presented at the 2011 meeting of the American Physical Society's Division of in Baltimore, Md., Nov. 20-22.

According to VirginiaTech Alex Villanueva, Robojelly looks very similar to an actual jellyfish. "Its geometry is copied almost exactly from a moon jellyfish [Aurelia aurita]," he said. The robot is built out of silicone and uses shape memory alloy (SMA) actuators to swim.

To move through the water, the natural animal uses the bell section of its body, which deforms and contracts to provide thrust. The lower, or lagging, section of the bell is known as the flexible margin, and it deforms slightly later in the swimming process than the rest of the bell. Until recently, however, Robojelly lacked this crucial piece of anatomy in its design.

Villanueva and his colleagues tested a number of different designs for their robot, some with and without an analog to a flexible margin. Initially, the used in construction presented a problem. Unlike their natural counterparts, the artificial materials tended to fold as they deformed, reducing Robojelly's performance.

After testing a number of designs and lengths for the folding margin, the engineers discovered that cutting slots into the bell reduced this unwanted folding effect.

This gave Robojelly a truer swimming stroke, as well as a big boost in speed.

"These results clearly demonstrate that the flap plays an important role in the propulsion mechanism of Robojelly and provides an anatomical understanding of natural ," said Villanuerva.

Explore further: Innovative scientists update old-school pipetting with new-age technology

More information: The talk, "Effects of a flexible margin on Robojelly vortex structures," is on Tuesday, Nov. 22, 2011. Abstract: http://absimage.aps.org/image/MWS_DFD11-2011-001706.pdf

Provided by American Institute of Physics

5 /5 (6 votes)

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User comments : 6

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Isaacsname
4.7 / 5 (3) Nov 22, 2011
It'd be nice to have a video , at the least.

You guys ever see this one ?

http://www.youtub...itFkSNtk
antialias_physorg
5 / 5 (1) Nov 22, 2011
this vehicle was designed to conduct ocean underwater surveillance, enabling it potentially to detect chemical spills, monitor the presence of ships and submarines, and observe the migration of schools of fish.


Awww. Doesn't that sound nice.

(...not to mention they'll find it useful for infiltration, placing mines, etc.)
It's the underwater version of the Predator drone.

Not knocking the technology - I think it's pretty awesome...but these euphemistic descriptions of what they want the thing to do - coming from the Office of Naval Research - are just so ridiculous.
Why don't they just admit what they want to do with it? No one is fooled.
moj85
5 / 5 (1) Nov 22, 2011
Also, whats to stop a shark from tearing this thing apart?
Nerdyguy
1.9 / 5 (9) Nov 22, 2011
this vehicle was designed to conduct ocean underwater surveillance, enabling it potentially to detect chemical spills, monitor the presence of ships and submarines, and observe the migration of schools of fish.


Awww. Doesn't that sound nice.

(...not to mention they'll find it useful for infiltration, placing mines, etc.)
It's the underwater version of the Predator drone.

Not knocking the technology - I think it's pretty awesome...but these euphemistic descriptions of what they want the thing to do - coming from the Office of Naval Research - are just so ridiculous.
Why don't they just admit what they want to do with it? No one is fooled.


From the National Academies of Science. Your predilection towards making overly dramatic and accusatory statements about all things U.S. & military will sometimes lead you down the wrong path. Bottom line, ONR does lots of non-military science.

http://www.nap.ed...mp;page=
antialias_physorg
not rated yet Nov 23, 2011
ONR does lots of non-military science

So does the NIF (the fusion experiments going on there come all under the heading of optimizing bombs through better fusion simulation).
If you look at their mission statements they're military installations/organisations. Do you really think anything that is financed through the DoD doesn't at least get looked at in terms of its military implications (or even gets started if it doesn't at least have some marginal relevance to it)?

What do you think they are? A bunch of altruists?

They're
Nerdyguy
1.5 / 5 (8) Nov 23, 2011
ONR does lots of non-military science

...Do you really think anything that is financed through the DoD doesn't at least get looked at in terms of its military implications (or even gets started if it doesn't at least have some marginal relevance to it)?

What do you think they are? A bunch of altruists?


No. Altruism has nothing at all to do with it. Congress has mandated that a certain amount of dollars go towards research where the objective is non-military civilian-side transfer. It's all there on the site I linked above.