Testing "motors smoothing patch" of the "PX4 Autopilot VTOL" code

We tried to put a smooth motors transition in the "PX4 VTOL" code.
This video shows the results we obtained after a little tuning, using a "Pixhawk flight controller" and "U-Blox M8N gps".
Special thanks to Roman Babst and Lorenz Meier, who are working hard to make their code safe and powerful.


Views: 1926

Comment by Chris Card on December 21, 2015 at 1:57pm

Wow , that's great!

It looks so surreal  [ @ 3:10 ]  to see the plane just 'hanging' there as though it were hanging on a string.


Comment by Charles Wannop on December 21, 2015 at 6:20pm


Comment by Rana on December 21, 2015 at 6:55pm

Really awesome !

Comment by Ravi on December 21, 2015 at 7:25pm

Great Job! sure this is the next in thing for this community. everyone is waiting for the code to be practical. people like me who are into fixed wing and into multirotor are eagerly waiting for the code.

Comment by Marco Robustini on December 22, 2015 at 1:53am

At the moment the APM Dev Team has no plans to work at their VTOL code, or at least i'm not aware of this thing.
The code in my video is "PX4 VTOL": https://github.com/PX4/Firmware

Comment by Jiro Hattori on December 22, 2015 at 2:02am

Actually, my feeling is that PX4(http://dev.px4.io/) shows more clear vision of development.

Comment by matucha123 on December 22, 2015 at 8:42am

Actually there is some start at VTOL code: https://github.com/tridge/ardupilot/tree/quadplane-wip

Comment by Andrew Tridgell on December 22, 2015 at 1:04pm

hi Marco,

I am actually working on quadplane support for ArduPilot. I have it flying now in a simulator with the addition of a 'Hover' mode in plane, along with auto-transition. See my quadplane-wip branch.

I don't think it will make the 3.5 plane release (as that is basically done already) but I expect it to be an option in the release after that.

We've been flying a larger quadplane (a senior telemaster) with dual-Pixhawk, and we're building a smaller one based on a Firstar 2000 now, which will run the quadplane code on a single Pixhawk.

Initially I think we'll just have two extra modes for plane. One is 'Hover' which will behave like copter stabilize mode. The other will behave like alt_hold mode for copter. I may even call it alt_hold, although I am a bit afraid people will think it is for conventional fixed wing and be disappointed :)

Later I'd like to integrate it properly into navigation code for precision auto-land.

It is amazing the amount of code that comes out of development for the outback challenge :-)

Cheers, Tridge

Comment by Marco Robustini on December 22, 2015 at 3:33pm

Interesting Tridge, keep me informed about your progress, thanks!

Comment by Andrew Tridgell on December 26, 2015 at 4:04am

Hi Marco,

Do you want to be the first person to try ArduPilot QuadPlane?

I've put a pre-built firmware here:


It is the same as plane master but with 3 extra modes:

  • mode 17: QSTABILIZE (same as copter stabilize)
  • mode 18: QHOVER (same as copter alt_hold)
  • mode 19: QLOITER (same as copter loiter)

You'll need to set the FLTMODE* parameters as numeric values as your GCS won't understand these values yet.The code assumes a Quad-X frame, with the motors on outputs 5 to 8. The normal plane outputs are assumed to be on 1 to 4.

You can transition between any modes, fixed wing or quadplane. The transition rules are:

  • if you transition to MANUAL then the quad motors will immediately stop
  • if you transition to any other fixed wing mode then the quad will continue to supply lift and stability in a hover until you reached the ARSPD_FBW_MIN airspeed (or airspeed estimate if no airspeed sensor)
  • once that airspeed is reached the quad motors will slowly drop over Q_TRANSITION_MS milliseconds (default is 5000, so 5 seconds)

You need to set Q_ENABLE to 1 to enable the QuadPlane functionality. All QuadPlane specific parameters start with Q_, so just set Q_* parameters as needed (they are very similar to the normal copter parameters).I've tested it in a simulator and it works nicely, but it has never been tried on a real aircraft. Let me know if you give it a go!

Code is here: https://github.com/tridge/ardupilot/tree/quadplane-wip

Cheers, Tridge


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