Dual-motor tailsitters

@tridge May I ask why transition looks so completely different (smoother) on px4 (almost three years ago) ? http://px4.io/portfolio/caipirinha-tailsitter/

Also why do we have two semi-identical codebases anyway? Makes no sense to me.

@palm369 May I ask what you mean by “semi-identical codebases”? I assume you are talking about the PX4 and ArduPilot flight stacks, and they don’t look very similar to me.

The last time I looked, the PX4 VTOL logic used the same transition strategy for quadplanes and tailsitters. In ArduPlane I don’t believe there is currently any attempt to smooth the tailsitter transition; the vehicle pitches forward at maximum allowed pitch rate. While it might be preferable to slow the transition down a bit, a tailsitter should certainly be capable of a fast transition from hover to fixed-wing attitude.

@lorbass Thanks for the advice on Dashware:

I mean that afaik both where the same in the past and got split up into two projects when 3DR was active on development. Why dont they merge them? Are there different development goals for the two projects?
Afaik they both doing the same thing on same Hardware. Ain’t see no diffrence.
Also lot devs are in both projects.

There are a lot of reasons, some Googling can help you find them.

@palm369:
ArduPilot and DroneCode

Rolf

According to the Documentation PX4 VTOL an airspeed sensor is used to determine when to switch to plane mode after accelerating in hover mode.
In the PDF Documentation a special setup is described without airspeed sensor.
In this case it is needed to set a Transition Time to accelerate.

And as Tridge advised he will work out other transitions.

Thanks you, I’m looking forward to it.:grinning::+1:
Otto

Found this, https://youtu.be/-bQdrvSLqpg … anyone know how to integrate this to Ardupilot, I need all the help I can get with P I D understanding.

Will take a bit of digging, but there is actually an Ardupilot balance bot codebase somewhere in GitHub, from about 5 years ago (apm2.5).

Instructions: https://makezine.com/projects/arduroller-self-balancing-robot/
Source here: https://github.com/jason4short/ardupilot/tree/ArduRoller

Hi, James, looking to understand /visualize PID tuning more in depth as it relates to( TVBS) twin vector belly sitters and Ardupilot. But it looks like that will be interesting as well… Thanks

Sorry- misunderstood. I thought you wanted to build a balance bot, in order to visualise pids and tuning.
We should probably put together a video explaining the 20 or 30 tuneable params, as ArduPilot is a bit more sophisticated than a simple pid loop. There are a number of “what are pids” videos (https://youtu.be/0vqWyramGy8 for instance), but they only scratch the surface really.

love that video idea! lots of head scratching about those 20 or 30 params.

Or hundreds of testflights or Rig tests as actually for mine including hours of log analysing
to get this result :wink:

“Old” Transitions still risky, flower bed helpful for “autolanding”.


Log: https://drive.google.com/file/d/0Bxldq38bfbqHa25ja09jTXZ0MUE/view?usp=sharing

No more “Flameout” when FBWA to QSTABILIZE
David detected the reason for the Flameout: FBWA to QHOVER or QLOITER. Thank you.

Otto

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Hi Otto,

gratulations, first backtransition with somersault backward (at 06.40) :grinning:
Thanks for the extensive measurements and hints.

Rolf

  • CG at 1/3 root chord

  • Flaps angle 45°

  • Flaps width 1/3 root chord

  • stable hover at 30° pitch with almost no flap deflation

  • Backtransition fine when going to QStabi

@tridge maybe it would help to

  • allow weathervaning to point a side in the wind
  • make two parameters out of the angle limit for hover -> separate pitch and roll limit

LOG: https://www.dropbox.com/s/4cwr0qptrpdpp0n/00000010.BIN?dl=0

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Just some fun with transitions.

Reduction of Q_A_ACCEL_P_MAX from default 110 000 in steps of 10 000 down to 20 000 has no affect on the Transitions.(Visual and Log)

Just saw beta release of Plane 3.8.3 https://github.com/ArduPilot/ardupilot/blob/plane3.8/ArduPlane/release-notes.txt

I am not sure if anything matter for tailsitter?

the beta isn’t actually released yet - I’m doing some work on tailsitters today. I don’t know yet if I will have something good enough for release though.