Scientists have created palm-sized swimming robots made out of soft, transparent silicone. They’re tiny, squishy, and equipped with video cameras — and they could one day be used for underwater surveillance or research.
The nearly invisible robotic creature, described in a paper published today in the journal Science Advances, resembles a tiny manta ray. (If its creators aren’t calling it ray-bot yet, they should be.) It has flexible silicone fins stretched across acrylic frames, and two electrodes: one sits inside the robot’s body, sandwiched between two sheets of “muscle” made of a polymer that shrinks when electricity runs through it; the other electrode is the water itself, where the robot swims.
In some of these clips, ray-bot has been dyed green to make it easier to see. Credit: Li et al. 2017;3:e1602045
When the scientists hook the little robot to an electrical tether or tiny little battery pack, the electrical charge causes the polymer “muscle” to flex. That allows the bot’s fins to flap and the silicon body to undulate. That motion propels the robot forward, swimming a lot like the manta rays that inspire its shape, the study says.
The little ray-bot can move surprisingly quickly: more than five inches per second, when it’s hooked up to an electrical tether. For scale, that’s more than the length of its body in a second — and faster than a rainbow trout, which averages less than four inches per second. Replacing the tether with a battery pack gives the robot more freedom to roam, but adding the battery slows the little ray-bot down to half speed.
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