Thrust vectoring coaxial Drone Update


 Just a quick update for the thrust vectoring coaxial drone project,


Maxxprod Himax contra-rotating brushless motor CR2805,

7x5 props replaced by T-Motor carbon fiber 9x3 resulting in more efficiency.

Flight time is about 15 minutes with Fatshark HD pilot and 12 minutes with a Gopro 3. Could be even better with a more adapted motor. The advantage of this system is to allow large props with little frame (the 3D printed frame of this coax weights less than 30 grams) resulting in a very good efficiency.

Flight controller is a CC3D revolution with a standard coaxial vehicle config.

The system seems to not accept too much the integral (often resulting in a counter pendulum effect during fast pitch forward translation but maybe it can be a variable overshoot??) but no pendulum effect with a simple P (no I nor D) for the inner loop (acro) and a simple P (no I) for the outer loop (attitude). With this config, the system reacts very good and is very stable and controllable even with wind.

Next step will be to remove the clevis in the commands because the system could maybe accept a direct servo in the roll and pitch plates and take advantage of a larger roll and pitch travel (-45°, +45° for ex) and more room in the frame (or a lighter one). CC3D will be replaced by a SP racing F3.

Thanks for your comments if you have!

Views: 8314

Comment by VGR-Systems on August 14, 2016 at 5:40am
Because i want to try cleanflight and take advantage of the floating point calculations of the stm32f3. I suspect an overshoot in the integer during fast forward when using integral-pid and gess that a float could avoid that... we will see:)
Comment by robert bouwens on August 14, 2016 at 10:09am

will this system be available for others?

looks very impressive.

Comment by VGR-Systems on August 14, 2016 at 10:52am
Yes, of course. Even if i'm working on a second version possibly with a carbon frame, i can share the 3d printed parts maybe on thingiverse. I will try and post the link here. Thanks for your comment.
Comment by robert bouwens on August 14, 2016 at 11:42am

excelent news!

Comment by Greer Carper on August 14, 2016 at 1:49pm

I could see a lot of applications in very quick point inspections!

Comment by Paul Schreiber on August 14, 2016 at 3:44pm

Though you have enlarged the prop diameter I still think the disk loading is pretty high in comparison to an average quad. And that really matters in terms of flight time.

Basically you could double your flight time, if you double the props diameter. So you need motors with more torque to turn the larger props etc. And the other question is, how does it effect the flight dynamics. You may should test even larger diameter to increase performance!?

Comment by Digital Wings on August 14, 2016 at 7:08pm
This looks amazing. Nice job!
Comment by VGR-Systems on August 15, 2016 at 12:59am

thks all,

@Paul, you're right, the disk loading is still very high, even if the flight time is pretty good due to the the low weight of the frame (less than 30g). But it's the max i can get from this motor from Himax without firing it (I tried...:)). Contra-rotating motors are quite rare and especially designed for planes (high Kv). That's why i'm working on a new experimental motor which is a little beyond my "garage" capabilities but no matter! I'm trying to transform two T-motor antigravity 4004 motors in one 4004 contra-rotating motor in order to have a very high torque low kv CR motor which can drive a 15" carbon prop. With this new design and a GEB8043125 1C Lipo, I'm sure it's possible to lift a go pro for one hour and take a real advantage from the global design comparing to an average quad! And for the flight dynamics, I don't like theory so we'll see in flight test! I'll keep you inform in this blog! thks for your comment!!

Comment by The Sun on August 15, 2016 at 10:58am

Very interesting, theoretically I term should never affect the transient performance of a system, especially not make it unstable. There are exceptions to this, you may find that introducing the zeros from your I term in your transfer function is somehow producing a very odd root locus. I doubt changing controllers will affect this in any way

Comment by Drone Tinker on August 15, 2016 at 11:44am

a vtol solution with aspects of this frame would be interesting.


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