
DuoCopter - based2
http://www.research-drone.com/en/DuoCopter.html
======
phreeza
Here is a somewhat similar design, from 2016. It uses gimballed rotors at
either end instead of modulating the angular velocity within a rotation cycle.
Seems more sensible to me to do it that way, and it shows fully controlled
flight (even flips it over at one point) instead of the little hop in TFA.

[https://www.youtube.com/watch?v=b14_XQ5nd2A](https://www.youtube.com/watch?v=b14_XQ5nd2A)

~~~
hatsunearu
Really curious how that thing generates torque since it doesn't have
asymmetric props.

edit: I'm dumb, it has gimbaled props. That makes OP's link much more
impressive, since that thing doesn't require gimballing which is expensive.

~~~
phreeza
yea there is another top level comment by gtirloni which links to a different
example which does it without a gimbal, by applying a sinusoidal current with
variable amplitude and phase to the motors. They have symmetric rotors though,
so your question applies there! I wonder if maybe the rotors are in fact
slightly asymmetric and just look symmetrical.

edit: I got it, this is super neat: The blades are hinged at a 45 degree
angle, but in opposite directions. See Figure 1 and 2 here

[http://www.modlabupenn.org/wp-
content/uploads/paulos_an_unde...](http://www.modlabupenn.org/wp-
content/uploads/paulos_an_underactuated_propeller_IROS_2013.pdf)

~~~
hatsunearu
Yeah, that still requires moving parts on the rotor. OPs design requires no
additional moving parts. I like it.

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gtirloni
Similar design: [http://spectrum.ieee.org/automaton/robotics/drones/flying-
ro...](http://spectrum.ieee.org/automaton/robotics/drones/flying-robots-stay-
stable-with-just-one-motor)

Re: Patents. My understanding is that it doesn't need to be "revolutionary" to
be patentable.

~~~
lucb1e
> My understanding is that it doesn't need to be "revolutionary" to be
> patentable.

How would one measure revolutionaryness anyway? If it hasn't been done before
and isn't just a variation on an existing thing (e.g. sports car but in
green), that sounds like a good enough thing to award a patent for.

Which is not to say that I agree about all the details, e.g. that software
should or shouldn't be patentable, or how long a patent should be valid, etc.
Just that one can get a patent for something that's not "revolutionary" makes
sense.

~~~
georgemcbay
Thomas Jefferson would disagree with you strongly, he was quite clear that he
believed patents should require a very strong degree of novelty and
differentiation:

See, for example:

[http://www.let.rug.nl/usa/presidents/thomas-
jefferson/letter...](http://www.let.rug.nl/usa/presidents/thomas-
jefferson/letters-of-thomas-jefferson/jefl220.php)

Sadly we've strayed very far away from how Jefferson thought patents should
work in this age of "This thing... but on a computer" patents.

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polygot
They have another design that can go from 0km/hr to 100km/hr in 1.5 seconds:
[http://www.research-
drone.com/en/extreme_climb_rate.html](http://www.research-
drone.com/en/extreme_climb_rate.html)

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jimnotgym
What is not proven for me is that this is more cost effective than the
quadcopter. The unbalanced rotors look like they will need expensive bearings.
The complex speed control looks like it is going to be very expensive by the
time they have tackled the efficiency issues. This is vs using just two more
identical motors. This brings economies of scale, plus you can use smaller
motors. The efficiency issue alone may mean a quadcopter needs less battery
capacity, allowing a lighter payload. Always interested in a novel design, but
still lots to prove

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prbuckley
This is a cool design. I think the group from University of Maryland developed
a single motor single actuator drone back in 2009, here is a link to video...

[https://m.youtube.com/watch?v=u23Hqq8QbeE](https://m.youtube.com/watch?v=u23Hqq8QbeE)

And article about students involved...

[http://eng.umd.edu/news/story/maple-seeds-inspire-robotic-
fl...](http://eng.umd.edu/news/story/maple-seeds-inspire-robotic-flight)

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phreeza
It appears to rely on slowing down and speeding up the rotation within a
single cycle. I imagine that would be quite wasteful, unless there is some
kind of regenerative process involved, ie dumping the power into a capacitor
and then releasing it again, or something like that. Does anyone know how one
would do that?

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steeve
FTA:

"By means of a further developed motor controller, the battery can be charged
efficiently with the brake energy. This works with high efficiency as with a
flywheel. For acceleration, energy is removed from the battery."

~~~
phreeza
Interesting. I would have thought the battery is not the right place to store
that energy, as it will be literally doing thousands of cycles per minute...

~~~
seanp2k2
Yeah, sounds like a job for a capacitor. Still, you're going to have lots of
losses vs just not using the extra energy in the first place. Why not do
something like a swashplate (
[https://en.m.wikipedia.org/wiki/Swashplate_(aeronautics)](https://en.m.wikipedia.org/wiki/Swashplate_\(aeronautics\))
) like helicopters? Instead of varying the speed of the blades, just vary the
_pitch_ of the blade during rotation. But then you've just invented the
helicopter. Use counter-rotating blades if you really want to eliminate the
tail boom, see [https://aviation.stackexchange.com/questions/8642/how-
can-a-...](https://aviation.stackexchange.com/questions/8642/how-can-a-
helicopter-be-designed-without-a-tail-rotor) for some example prior art).

My first thought when seeing this is also around the longevity of those poor
bearings, given the eccentric load. I wonder how much this would benefit from
a motor with many more poles (to control the rotational velocity to a finer
degree) and the lightest props you could find (CF is already used extensively
in RC help blades). I also wonder if it'd be possible to use a horizontally
hinged blade which could shoot forward + rock backward in a controllable
fashion to control how much lift you get during a particular phase of
rotation. I'm sure this is not a new idea.

~~~
jasonwatkinspdx
The whole point is to avoid the complexity of swash plates and similar
mechanisms. This is just two rigidly mounted motors with asymmetric props.

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Justin_K
Why are there so many claims without even a demonstration of them?

~~~
whoami_nr
What do you mean exactly ? There is a video embedded with the drone in action.
What claims do you imply ?

~~~
Justin_K
The site and video claim all kinds of performance benefits, a better video
picture, longer flight range, higher efficiency, quieter, etc. The video shows
it flying about 5 feet and then a bunch of motion graphics. There's no
substance to this design. If all the claims are true, I'd love to see it in
action and learn more. If you go by just the video, it can barely get off the
ground. Not so innovative when you look at it like that.

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Havoc
Nice. What about vibrations?

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forkLding
I understand that the author is trying to sell us the product and get it
developed but what are the cons of using a duocopter vs your normal quad? I
generally think of decisions as tradeoffs and want to know the cons as well
when considering an option.

Note that I'm just an drone enthusiast in that I buy and use them but I do not
develop or go DIY which is why I ask this question.

~~~
srbl
As a fellow enthusiast, this doesn't look particularly agile (or fun).

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callesgg
Cool.

I struggle to think of a scenario where this would be a better fit that a
quad-copter.

Maybe where the with of the aircraft is a major problem, in some sort of
tunnel or suer.

~~~
serf
>I struggle to think of a scenario where this would be a better fit that a
quad-copter.

single-engine controllable aircraft is one example in the demo video. They are
showing off the algorithm; not the platform.

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amelius
Patent protected and not revolutionary.

~~~
nannal
>not revolutionary

Well it does revolve so...

------
shujito

        >Inexpensive
    

Consumer-wise or manufactor-wise? I'm thinking the latter

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cityzen
that 1 second of "stable hovering" really sold me.

(spoiler: it didn't really look that stable)

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LASR
Is it just me or does this seem to be a scam? My BS detector is going off
every second of this video.

I have a feeling the inventor is looking for cash with no substantiated
product built.

~~~
geezerjay
> Is it just me or does this seem to be a scam?

My thoughts exactly. It's such a long video but it essentially consists of a
series of crude animations peppered with very short and unsubstantial footage
of what appears to be an implementation shown afar doing practically nothing,
and even so while displaying a warning message as it's just a prototype.

This does look like a half-baked scam.

