AeroVironment's Mola Robot Flies Underwater on Solar Power

Check out AeroVironment's new robotic fish, a solar-powered sunfishbot

2 min read

Evan Ackerman is IEEE Spectrum’s robotics editor.

AeroVironment's Mola Robot Flies Underwater on Solar Power

A mola, or ocean sunfish, is a very big, very flat, and (in this reporter's opinion) rather silly looking tropical bony fish. Aerovioronment has used the sunfish as an inspiration for one of their latest proof of concept robots: Mola, an oceangoing robot that's powered by the sun.

This, just for reference, is what a real mola (a large one, probably weighing about 1,000 kg) looks like:

The pic on the right shows a behavior called "basking," where a sunfish will sometimes float along up at the surface on its side. It's thought that this may be an invitation for birds to land on the fish and peck parasites out of its skin, or it could also simply be that the fish is sunning itself to help it digest food. Either way, Aerovironment's new Mola robot does the same thing, except it's more interested in charging up its solar panels and less interested in being pecked by birds:

Solar power may not seem like the greatest idea for a robot that's designed to spend the majority of its time submerged. In fact, the robot is programmed to stay as deep underwater as it can while still getting enough power to move. The nice thing about using solar panels on an aquatic robot, though, is that you can make them very durable for cheap, you can power your robot for indefinite periods, and if you need more power, you're not restricted by space: with the whole ocean to play with, adding a tail of additional panels is no problem.

Even under ideal conditions, the amount of power that the Mola robot can get isn't very high: AeroVironment says that only about 5% of the energy hitting the top of the ocean surface makes it through into the water, and that power decreases linearly with depth. The robot seems to manage pretty well, however, and it's worth noting that there are no on-board batteries: the robot is collecting and using solar power in real-time to drive itself at nearly four KPH while also powering a data logger that records physical, chemical, and biological information.

This version of Mola (which might be the second generation of the robot, we're not entirely sure) is a proof of concept, whatever that means. But there's clearly a market for long-duration ocean going robots, as evidenced by the popularity of Liquid Robotics' Wave Gliders. And with AeroVironment's history of successful bio-inspired robots, we're hoping that they'll be making something of this, and that at some point, they'll offer to let us go diving with it.

Also, I just looove Mola's cute little finses. That is all.

[ Aerovironment ]

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