AirBurr UAV experiments

[Keith Mc]

There is a lot of interest in UAVs these days
(Unmanned Aeriel Vehicles, aka flying drone robots),
like the quadrotor style "quadcopters".

But here's another UAV approach, that's quite interesting,
and has high potential for DIY UAV hobby experiments:

The AirBurr Project: Robust Flight in Cluttered Indoor Environments
... http://lis.epfl.ch/airburr/
Check out this video:
... http://www.youtube.com/watch?v=GgdI0oiPY0s

Instead of a quadcopter's 4 motors, it's a "flying egg", with only 2
facing concentric prop motors, and a pair of servos running an X-vane.

This gives you a number of advantages over quadcopters:
- 2 vs 4 prop motors - Cheaper, and if the other hardware
is light enough it MAY have more flying time.
- Simpler control algorithms (but, code is "weightless" AND a one-time cost...)
- Geometry & CG gives higher inherent stability (it's "pendulum-like")
- Uses identical standard props, vs having to find matched LH/RH pairs.
- Doesn't require as many sensors on board, JUST to fly.
- Resilient to collisions, with a self-righting ability.
(If it is grounded, it just rights itself and takes off again! :-)

Disadvantage:
- Thrust is on centerline, so IF you intend to lift something
you have to think hard about airflow. Quadrotors may be a better
choice for dangling things below it, like cameras or object
pick-n-place contests. But as a simple flying camera-droid UAV
(vs a "lifter"), IMHO this "flying egg" is a great choice.

Question - Do you guys think this would be cheaper & easier to
make, and/or longer flying than a quadcopter? (esp with something
like the cheap $5/pair flyweight micro-servos Paul H once found.)

*** PAUL - Do you still have a link for those $5/pair micro-servos?

I'm not sure, but control is so much simpler and stability is inherent,
you may even be able to get away without an onboard computer
and sensor suite, and just use a basic R/C rig with servo mixing to fly it.

Bumper cage - Try my recycled windshield wiper stainless
steel strips. (FREE, in every auto supply's outdoor trash bins,
the day AFTER a rain. :-) Yea, they're not as light as carbon fiber,
but they're a whole lot cheaper!

QUESTION: How do you easily weld stainless steel strips together?
What's the proper welding tech? (A DIY cap discharge spot welder?)

Hmmm.. If you make the bumper egg or teardrop-shaped, and
get the CG right, you MAY be able to get away without the
legs, by making it act like a "Weeble" toy and be self-righting:
... http://en.wikipedia.org/wiki/Weeble

So... Thoughts? IF you ever wanted to attempt a UAV copter,
WOULD this be a better or cheaper choice than a quadcopter?

How would YOU make a UAV?

- Keith Mc.

[Keith Mc]

On Oct 24, 2012, Keith Mc <acti@...> wrote:
> This gives you a number of advantages over quadcopters:

> - Uses identical standard props, vs having to find matched LH/RH pairs.

Whoops... Upon reflection, I think I was wrong about that one.

You may still need to use matched LH/RH prop pairs with "flying egg" UAVs

- Keith Mc.

[Toby]

RH/LH props are not necessarily needed, nor two motors. There were
some older glow designs that used a rotating "duct" body with large
slow moving outer blades as the counter torque to the single ducted
fan central glow engine. Kinda like a gearless propfan.

The downside to the design as the whole device spins while airborn.
Upside is that a "fixed" 1D camera (or some regular 2D cameras if the
vsync can be driven directly) can take 360degree pictures with refresh
rate= the rotation of the craft. Coding fun! MEMS/piezo gyro can be
used to compute image stabilization.

As long as the CG is under center of lift, it should be dynamically
stable. Servo vane control timed at period of body rotation (think
electromechanical swashplate) would provide your directionality.

It is left an exercise to figure out the magnitude and compensation
for gyroscopic precession, and Heisenbug extermination.

On Wed, Oct 24, 2012 at 8:56 AM, sp...@thewynngroup.net
<sp...@thewynngroup.net> wrote:
> UAV is on my TODO list.
>
> Do we have a SIGUAV in i3?
>
>
>
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