"Hybrid" (PosHold) flight mode, what was missing in APM Copter now is reality!

During the alpha testing phase with the "APM Copter V3" code
i immediately reported to the Dev Team that the Loiter mode was very accurate but is not allowed to fly normally, like with other system as DJI and Mikrokopter, Zero-UAV, etc.
We preferred to make the Loiter mode that would serve to accurately reposition the multirotor, and to help beginners to fly slowly and safely.
An italian friend and developer, Sandro Tognana, collected my challenge and started to develop a flight mode as I wanted, in line with the other famous flight control board.
Another awesome programmer, Julien Dubois, has joined our team and has worked actively to implement the complicated wind compensation.
After several months of development and testing are pleased to present the "Hybrid flight mode", in two words a "flyable Loiter" with wind compensation, the code virtually switches from "Loiter" to "Alt-Hold" and viceversa when you exit and enter a sticks deadband (configurable), considering of course the compensation of the wind, therefore complies with the tuning of your multirotor.
You can configure some parameters but already with the default works perfectly, my video speaks for itself.

This new mode is currently being debugged (in alpha phase), it is therefore not available to the public, of course, will have to go into the hands of APM Copter Dev Team who will decide whether to adopt it in an upcoming release.
The results in my video are great, sorry but the audio is bad because it was very windy today, however, is clearly seen as a "Hybrid" works, is almost perfect.
In the second video by Julien you can see the Hybrid in action vs a "DJI Phantom 2" quad with "Naza 2" inside, imho Hybrid work better than the "GPS Position Hold" of DJI, especially on braking.
The tests were carried out on APM and VR Brain, but of course will work on any board that installs "APM Copter" as PX4 and Pixhawk.
I will keep you updated on the "Hybrid" developments, i'll open a discussion about this with other APM Copter developers to assess any changes in the code.

I want to say thanks to Sandro and Julien for their great work!

Bests, Marco

Views: 29713

Comment by Sergios Zafeiropoulos on January 14, 2014 at 1:04pm

Marco perche dici che PX4 e Pixhawk "suck" non dire cosi ...

scherzo !!

Comment by Josh Welsh on January 14, 2014 at 1:12pm

I like it Marco, pretty cool!  I don't like the name of the flight mode, as it is too broad and says nothing at all that it is a hybrid between Loiter and Stab, but, that's only a mere detail to work out.  Very cool, congrats to you and Sandro and Julien on an awesome development!  This is something I have wanted ever since day 1 of flying APM:Copter!

Comment by Josh Welsh on January 14, 2014 at 1:13pm

You may cover this in the narration, but since I can't understand it I'm wondering if you have any new params to govern flight speed, angle, etc, or if you rely on some existing ones?

Comment by Sergios Zafeiropoulos on January 14, 2014 at 1:13pm

With this arducopter will be waaaaay ahead of the competition .....

Comment by Brit Davis on January 14, 2014 at 1:29pm

wow, this looks great. Responsive and smooth. No subtitles needed! Thanks Marco!

Comment by Gary McCray on January 14, 2014 at 1:32pm

Really great Marco and team, much more evolved piloting capability than Loiter.

Does need a better name than hybrid, maybe: "Cruise" ?

Look forward to this making it to our beta.

Comment by Michael Pursifull on January 14, 2014 at 1:37pm
One way to maybe know it's a new alpha code feature: Marco is flying a small 'copter and not one of his big birds :)
Comment by Julien Dubois on January 14, 2014 at 1:48pm

@Josh: Actually, there will be the fewest params possible (we've 5 atm, and will reduce to a minimal value as some of them were just here to debug and tune the code). Whatever copter type, for the moment, the best params are always the same, so we could even use no param!

Loiter code is only used to stay at a fixed position with a null speed (related to ground), so the default arducopter params are good enough. BTW, congrats to loiter developpers because the loiter code gives even better results than the Naza's one in this case (fixed position).

The rest is a real Alt_Hold, so no more param required. Only the transitions (and the difficulties were there) would need some params to have a smooth behaviour. For example, fly alt_hold and engage loiter in flight, you'll see a hard twitch.

The hybrid mode makes this transition natural:

- it filters pilot's hard stick releases (a kind of radio exponential shape if you want but not exactelly),

- brings a smooth brake (manual like, and not "controller-like", so we've not the loiter slow/delayed/strict behaviour)

- makes smooth loiter engage.

- secondarily, there is a wind compensation that updates each time the copter is loitering and which is required for better brake and alt_hold phasis


Comment by Rob_Lefebvre on January 14, 2014 at 1:49pm

Maybe adopt the standard name for a mode like this: "Position Hold" ?

Josh, my understanding is that there are no parameters for this.  When the stick is released, it's in Loiter.  When you push the stick it is in Alt Hold (?).

Sort of.  It's not quite pure manual control, but I'll let Marco explain.

Comment by Luciano Zanchi on January 14, 2014 at 1:51pm


That's great function! 

Thanks to you, Sandro and Julien for this development. Can't wait to test it myself!


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