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

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It's at 5.0, should I increase it or decrease it?

I ask that because it looks like your still Yawing a bit back and forth. 

So while still feeling like there's still very very little information out there for tuning Yaw, here's what I am currently running:

Stab Yaw P - 9

Rate Yaw P - .8

Rate Yaw I - .12

Rate Yaw D - .004

Imax: 1000

I think I read somewhere that a Stab Yaw P greater than 6 does nothing, but I don't know if that's true or not. I just kept increasing it and it seemed to improve more, but maybe over 6 I was seeing some confirmation bias instead. Hard to say. The wiki is pretty useless for tuning Yaw so who knows... 

But I found that the defaults are just way, way, WAY too low. The more I kept pumping it up, the tighter it got. And I think that's the idea. Keep pumping it up and watch it tighten up more and get better and better, then when it gets worse, back it off a little. It's very hard to tell sometimes and it's hard to know what to look for at times as well (again, the wiki is useless here). I wish it were easier, but maybe the Disco is just a tricky beast to tune. I'm too new to know the difference. :)

http://copter.ardupilot.com/wiki/arducopter-parameters/#Yaw_axis_ra...

http://copter.ardupilot.com/wiki/arducopter-parameters/#Yaw_axis_st...

There you can read the limits, can you show me any videos with those PIDs? Or any screenshot at least?

Exactly, but what do the limits mean? The definitions don't mean much to me, not being an expert on the matter. Stab Roll and Pitch say they have a max of 12 and I'm almost there (currently they're both over 10). So why can't I go over 6? What does that limit mean? There's no error or message when I input something higher than 6 so I really don't know. Just not a lot of information or explanation to work from.

Let me see if I can find something. I'm running a Disco Pro, so it might be a little different than a standard Disco (the pro is probably a little heavier in most cases?). I haven't been testing/checking yaw performance in a while, mainly because it's been a bit better, but let me see what I can do. 

Lately my issues have been with a jittery gimbal and phantom vibrations that appear and disappear at the drop of a hat, so there's always SOMETHING to work on. :) 

I have a TBS Discovery with a Tarot gimbal mounted in front so yaw PIDs should be the same or at least pretty similar

Cool. Well if you have a chance, try out my Yaw settings and let me know how it goes. I wouldn't say my settings are perfect (always room for improvement!), but they're pretty good and the best I've found thus far on the Pixhawk. 

thanks, I'll definitely do that, also if you can find any of your videos with those pids I would really appreciate it

So today I tried to improve my TBS Discovery YAW PIDs even more, this is my best setting so far and I'm starting to get pretty happy with the result

STAB_YAW_P 6.0
RATE_YAW_P 0.50
RATE_YAW_I 0.05
RATE_YAW_D 0.05

Reading the description the max value for the D is 0.02 so no idea if this makes a difference, comparing it vs 0.004 which was the value someone recommended before is a lot better tho.

You can see they're pretty good in the graph, the difference between des_yaw and yaw at the end is because i was descending pretty fast

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Thank god, I found this thread at last  - it means I'm not alone :-)

I too have yaw issues on my camera hex that seems to be the same as guys are having here. It's good to see that you can really ramp up the rates and stab without making it unflyable!

Did you eventually get a setup you were happy with?

My video sample - you can see the yaw problem occurs at all speeds, from loiter to fast forward. Fast forward to 00:30 and you can see it.

Hi everyone, I'm desperately trying to understand yaw tuning as well. I have a QAV400 with a gimbal and it flies great except for the yaw issues:


1) It tends to want to go straight (which is nice) UNTIL I want to make a very gradual, wide turn. Then it seems to resist my stick input until I've given it a little too much stick and it starts to turn more than I want. This results in me having to correct.


2) If I try to do a REASONABLY tight turn while keeping a forward speed, my quad starts to do the turn but then "spins out" and does a 180. I'm using stabilize or alt-hold modes.

Hi Robert, I would be interested in seeing a log of a flight showing a string of these problems.

Hi Leonard,

Thanks for the reply. I've done AutoTune but I'm still using the default settings for yaw. Here's a video of my last flight and I'll attach the log file:

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