Guys,
I need some help in setting up yaw PID's. My TBS Discovery with APM2.6 has a poor yaw performance. It seems not very locked and what is most annoying it is slowly oscillating which is most visible in onboard video footage.
To get to the root of the problem I did some log analysis and found that actual_yaw is indeed tracking nav_yaw but leaves some +-3 degrees slow oscillations. Please have a look at this log screen and my current PID's. Any ideas where to start or how to systematically set up the yaw PID's?
Thanks,
Michael
Replies
Tuning my Rate Yaw P up to 0.55 I had better results.
Will keep with Leonards advice and try to rise it up to 1
I have no idea how Yaw-Oscillation by too high values will look like.
Has anybody experienced that?
If my understanding of github is right, Autotune for Yaw is scheduled for 3.2
https://github.com/diydrones/ardupilot/issues/874
Same problem for me, but with Rate Yaw D = 0,0100 and enough IMAX its nearly good. At the beginning of anouncing AC 3.2 there are some posts from developers that they would add Yaw tuning to Auto tune for 3.2. But in between there is nothing in 3.2 with Yaw Autotune.
Same Problem with me:
My Setup: Tarot 680Pro with Tarot 4006 Motors and HQProp 12x6 on Pixhawk running APM 3.1.4
The log is with Stock parameters. Will keep tuning during the next days.
I had the Problem before with an APM-Clone on the Tarot and my little Quad, which didn´t show Yaw-Problems before(with HK AioP on APM 3.0.1)
And I never found a solution, which is why i bought the new FC.
Tried a lot:
I was able to get rid of some visible oscillation by tuning Roll and Pitch to the max, but the Overshoot remains.
And it is also still visible in Edgar Scotts postings.
Searching through the net, i found quite some people with similar problems and a lot of videos of people who obviously don´t bother. But no technical explanation and real solution.
Correct me if I´m wrong:
When Yawing the Multicopter Clockwise(CW) the CCW-Motors have to spin faster. When the Motors ought to stop, the CW Motors have to spin faster to stop the Rotation.
The heavier the Kopter is and the more weight is far from the center this response has to be stronger.
In our case the response is either not strong enough or too late. When it sets in, the copter overshoots again, trying to get to the desired yaw.
So, while normally you would lower the P Gains when observing oscillation, in this case it should theoretically be higher?!
I will keep tuning, but it would be nice to have some theoratical insight in the workings of the Yaw-controller, to know what we are doing.
I attached a log before tuning my Hexa.
It would be nice to resolve the issue.
I found one post, where somebody disabled his compass to get rid of the Desyaw heading which the yaw-controller never reaches.But that should´t be the solution.
Will research more.
Regards,
Nils
11.BIN
FWIW I have a few flying buddies that fly Phantoms and they all have about the same yaw oscillations as my APM Hex and Pixhawk Quad (both with 2 axis brushless gimbals). One of the guys finally bought a 3 axis gimbal for his phantom which yields really amazing video. It completely eliminates the yaw oscillations. For commercial quality video, a 2 axis gimbal is not quite there... a 3 axis gimbal does the trick.
For a week or so I flew 3.2 on both my multi-rotors (with the same tuning as with 3.1.4) and noticed that the yaw oscillation was significantly reduced. However, occasionally the Hex would dart off when selecting hybrid mode so I regressed to 3.1.4 which I have not had that issue with... but I have some basis for hope that with the new 3.2x code the yaw oscillations will be less of an issue.
In the mean time, this is solvable with a 3 axis gimbal.
Steve
I already ordered a 3axis gimbal but would really like to resolve this issue on the APM side.
Will see if I try 3.2 on my little quad on APM 2.6 during the next days.
Have to remember to switch logging off ;)
And perhaps I´m going to load 3.0.1 on the big one...
Im still having alot of trouble with my yaw.
anyone can help?
i have SaB p=5
Yaw p= 0,25
Yaw i= 0.01
Yaw D=0
imax 8
Quad Pixhawk.
2014-05-18 15-36-35.log
what frame are you using? I'm also getting oscilations with my f450
Im using a 550 custom made frame from Hobby king 650 frame.
I have very low vibrations so i dont understand where is the problem of this. it ruins alot of flight time and video.
Maybe Randy can tell us something about this because there is some guys with same problem.
I did 3 tests with diff PIDs all shown below
Started out with
Stabilize P 5.0000
Rate Yaw P 0.2500
Rate Yaw I 0.0100
Rate Yaw D 0.0000
Rate Yaw IMAX 8.0
Then changed Rate Yaw P and Stabilize P only
Rate YAW P 0.25-stab yaw 5.0
Worked GREAT
Rate YAW P 0.10-stab yaw 5.0
Looks not as good but okay
Rate YAW P 0.10-stab yaw 1.0
DO NOT TRY, 1.0 in the Stabilize P made it rock like a drunk driver, landing was hard as it was swaying
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