Lots of research, but I did not see a good process for initial setup of a quadplane. Specifically around flight parameter and control tuning.
As an example, my initial thought would be to flash the pixhawk with the copter code and tune as a multi rotor. However, is there a list or mapping of the final tuned parameters to extract from the copter Parameters and which q_* parameters to populate with the settings derived from the copter tuning?
Same for plane. If you don’t enable the quadplane functionality and you fly as a fixed wing and tune as a pure airplane - which parameters need to be transferred from the “plane” settings to the q_* parameters?
Or if all tuning is best to be done with the plane code and the quadplane functions enabled - what is the best process and order to follow? Auto tune yes/no? Manual flight and tweaking?
Looking forward to the responses and help. Looking to get a 40lb quadplane setup and working well using pixhawk/ardupilot.
It’s a good question, or set of questions, that may have answers that depend upon your skill set and comfort zone. In others words, you may need to determine what is best for your project.
When using the Plane code, you can manually tune or autotune flights for plane, not copter. There is currently no autotune for quadplane copter mode. However, there is no need to transfer plane settings as the Q settings are for the quadplane copter setup.
If you use the copter code to tune up the copter performance, I am not certain these parameters can be used as Q parameters without alteration. It is a question that I have not seen an answer for yet.
I’m my experience, I have done this approach several times with success.
- Fly the plane as a normal R/C plane
- Add the FC and fly as APM Plane (tune as needed)(bailout here is Manual mode)
- Add the copter parts and test hover as a quadplane (tune as needed)(bailout here is QSTABILIZE mode)
- Test transitions (bailout here is QSTABILIZE, QHOVER, etc. modes)
I have not found it necessary to use the copter code when testing a quadplane or tiltrotor. There are only a few critical parameters to adjust as written in the Wiki.
Thanks for the response. I was just concerned with such a large, heavy quad and lack of available PID’s to start from. Was wondering if the copter code is better at handling initial tuning corrections.
That the copter and q_ settings are not directly related makes me think that the copter code in plane is not the same as the actual copter-only code.
Even with the copter code, we had major issues initial flight testing a 54lb quad a couple years ago and had to put a DJI A2 in it. We followed the same process for it as a 30lb quad that was tough, but eventually got it tuned well. Anything under 15lbs seems to be no issue. Seems as size and weight increases the initial flights have increased pucker factor. On the 30lb quad we had one PID maxes out which concerns me - but again, it was 2 years ago and the code has changed drastically since.
Thanks again for the suggestions.
The copter and q_settings may not be directly related. There are other ways to affect the PID settings, if you max out, like cell count, prop size/pitch, etc. It would be interesting to see some photos of your intended vehicle. Not knowing the application, other than “big”, a tilt-rotor design may be favorable to a quadplane.
Another tuning method which you could consider is transmitter based tuning, which can be used if you don’t wish to manually tune all the quadplane VTOL parameters: http://ardupilot.org/plane/docs/common-transmitter-tuning.html
The catch is that the transmitter that you are using needs to have a knob or slider, that is able to be mapped to the tuning channel parameter in ArduPilot
I’m not sure if anyone is still monitoring this thread, but I’m trying to set up my first quadplane, or more accurately, a 6" quad running Plane with Q-enabled. I was trying to tune the Q PIDs earlier today. In QAcro I can easily tune them for a nice flying quad, FLTE terms are big (60 I think) due to the small size, But default Copter PIDs worked well. Comfortable to fly both LOS and FPV. Then i tried switching to Qstabilize, and it shakes like crazy. I tried changes in the ANG_P terms, but values between 2.5 and 6 don’t really seem to change the shaking. If I dumb down the RAT_P terms a bunch (roughly half), it stops shaking and flies ok in QStab, but if I go back to QAcro, it is barely flyable with the low RAT_P terms.
Any idea why the PIDS needed for Acro and Stab are so different, and apparently appear to be incompatible? Perhaps I’m going about tuning all wrong. My experience is most with Copter, and this approach has worked well.
Any suggestions would be most appreciated.