There is a WIP PR from two years ago…
I flew my rebuilt tailsitter again this week and another near disaster. I just need some advice about
relative aileron control (poor hardware excursion?). My elevons don’t appear to move more than the 50% up and down like in manual mode having a mixing gain of .5. Have increased mixing gain to 0.8 when making a transition from FBW to Q-Hover, or Q- Loiter, the elevons look to be above 50% , more like 75% up in transition and I wonder if this is enough.
Having taken off in Q-Stab, it drifted down wind and I didn’t seem to have any control to bring it back so I chanced Q-RTL and it changed to FW mode and returned with a transition to vertical at home point. But the plane stayed at the return height just loitering. I could not land it even with the thr at zero, it still hovered. Only way to get it out of the air was to switch to Q-Stab and try to land. It came down but did some damage.
The Q_M_THST_HOVER is at 0.1873336 and never seems to change even with Q_M_HOVER_LEARN set to 2. Obviously, this is the problem why it won’t hover at mid stick… Have added the
Data Log here…https://drive.google.com/file/d/1SUoP0YO8EB0yVckL9x6Rv3jBAxqvalHl/view?usp=sharing
Log shows it cannot hold desired pitch a lot of the time in VTOL, indicating either tune or control effectiveness…as the QRTL hovering forever…if it cannot reach the home point within a certain margin, it will keep trying to until it does, then begin its descent…am not sure if there is a timeout on the acquisition of attaining that position, but will investigate…I think it should bailout into QLAND…
as to bail-outs, if you have a problem with a tailsitter, its usually better to land on its belly in FBWA than crash vertically…at least on the types of tailsitters I fly …something to consider if its right for your vehicle or not…
edit: it would be too difficult to determine a reliable progress metric to home in that last phase, but one should be able to switch to QLAND or back to FBWA and land since its within Q_RTL_RAD and close by…
Nice, that’s really great to know. Apologies for the late reply, I usually get an email notification when I get a response from anyone.
Say tridge, what do you think of a touch-of-a-button feature in mission planner for the user to be able to choose which firmware version they want to use in SITL?
Consider reviewing my petition if you think it’s a good idea.
https://discuss.ardupilot.org/t/petition-for-us-to-choose-sitl-firmware-version/71778
Hi all,
Maidened my first scratch built non vectored tailsitter yesterday and was astonished at the performance of Qhover right out of the box. Ardupilot is simply amazing! 2 strange things happened though:
- on 3 consecutive flights after about 20 seconds of Qhover the vehicle went right into forward flight mode automatically. I don’t understand why.
- When it went into forward flight mode, it did so upside down - inverted - Again, don’t understand why as all my control inputs seem correct, Elevons are correct in Qhover, FBW, and manual modes.
Should I be using Qloiter instead?
Any help would really be appreciated! Thanks guys.
Other people have said as much has happened to their planes. Could be your c.g is too far forward and when you asked for too much pitch angle in Qhover it went too far and couldn’t right itself. You should try to fly your tailsitter in Qstabilize (aggressively) and see if something similar happens.
Also, what firmware version of plane are you using?
And if Qhover isn’t working then I wouldn’t try Qloiter. I would get these modes working in order : Qstabilize -->Qhover --> Qloiter.
Thank you @Shef. Using version 4.1. I have changed qhover to qloiter and sometimes it will loiter for about 20 seconds relatively well, but then always seems to have a hard time maintaining, so i switch into fbwa and it does so remarkably well and flies great. But it really struggles going from fbwa back into qloiter. Other times it will do as I described above and takeoff and darned near immediately automatically switch to inverted forward flight. I will try also try using qstabilize per your suggestion tomorrow (thanks again!) @hwurzburg I have attached a .bin file here 2021-06-05 19-49-08.bin (979.3 KB) Thanks gents!
Sorry, didn’t mean @hwurzburg, but was responding @iampete for the .bin file. Pete, this is one of the flights where he rose up off the ground in QSTAB and then seemingly switched over to inverted forward flight without my permission! 
That not what is in this log, its a very short flight in Qloiter. Pilot puts in full throttle vehicle takes off, throttles saturate and vehicle can no longer maintain control authority.
Please set ARMING_CHECK to 1
Peter, in your opinion is it absolutely positively necessary that I have a compass to have a working twin motor tailsitter?
Windwaning for Dual Motor TS >> Is it implemented in 4.1 beta1?
its not it yet, sorry
OK, we will wait for this implementation
You need some to test it first?
I have a tailsitter with a Holybro Kakute F7 AIO.
Can try this weekend if you like.
I am trying to do a maiden QHover of a dual-motor tailsitter running the Beta Arduplane. In manual mode the controls are good and in FBWA the controls do what we want for pitch and roll stabilizing in tests. In QHover if we lower one side that motor goes faster, so differential thrust is working.
We are holding the plane and trying to get it to hover in place and gradually let go. But within the range that we can hold it the throttle control almost seems on/off and not what we expected. We can not get it to hover in place and gradually let go. It seems like this should be possible. Any tips?
use QSTABILIZE where you directly control the throttle with the throttle stick…in QHOVER/QLOITER its commanding climb rate, not throttle…so when you get above mid stick commanding a positive climb rate it slams the throttle up trying to get that rate…below it turns off throttle trying to get a descent rate…
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That explains it. Thanks so much!
Hey, it just came to my mind that you could be intrested to see what we have achieve with Ardupilot tailsitter. The company is kinda new and we are still learning about everything but slowly getting there.
Thanks to this community
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fantastic, thanks for sharing!