
Harvard researchers create insect-sized robot that can both fly and swim - housedonuts
http://www.seas.harvard.edu/news/2015/10/dive-of-robobee
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bordercases
I don't really like the "flying submarine" angle, as historically interest-
piquing it might be. A lot of the success seems like it might come from the
scale that the machine works at, i.e. there are non-linear cost functions
involved when it comes to changing the scale at which the aerodynamics are
treated at.

But yeah, super cool.

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msravi
Why are all the robotic insects built with flapping wings, as opposed to
propellers or rotors that drones, airplanes, boats, and helicopters are built
with? Is there something inherently different at that scale that requires
flapping wings?

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nether
Yes, the tendency to shed vortices is much greater at small scales. A rapid
flapping motion is basically a vortex generator and more efficient than a wing
(rotating or fixed) which relies more on steady state, laminar flow. See
[https://en.wikipedia.org/wiki/Reynolds_number](https://en.wikipedia.org/wiki/Reynolds_number)
for more explanation.

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mtrpcic
Additionally, the energy required (relevant to total mass) to generate lift is
a lot smaller at this scale thanks to the Square-cube law[0], and it's a lot
more efficient to flap a wing on an as-needed basis than to run a rotor at a
continual and steady rotation.

[0] [https://en.wikipedia.org/wiki/Square-
cube_law](https://en.wikipedia.org/wiki/Square-cube_law)

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tomcam
This version seems tethered to a power source and not self-contained with a
battery.

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jawarner
I'm impressed by the simplicity of this design. How much control can you get
out of the robot over that power cable? Is timing and computation done on the
robot itself, or on the other side of the wire?

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Nzen
2012 2min vid about inspiration, construction, & control :
[https://www.youtube.com/watch?v=K6PpCTMEAVM](https://www.youtube.com/watch?v=K6PpCTMEAVM)
. There _is_ a processor onboard that controls the flapping.

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hising
Did not read, only watched the video. It seems that it can go from flying to
swimming, but can it go from swimming to flying?

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seangrant
"While this RoboBee can move seamlessly from air to water, it cannot yet
transition from water to air because it can’t generate enough lift without
snapping one of its wings. Solving that design challenge is the next phase of
the research, according to Chen."

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petersouth
sweet, we need to use these things to pollinate when the bees die out.

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mhb
Once they figure out how to power them.

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hugh4
Honey.

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dang
Url changed from [http://bgr.com/2015/10/29/harvard-robobee-fly-swim-
insect/](http://bgr.com/2015/10/29/harvard-robobee-fly-swim-insect/), which
points to this.

