Autotune questions

ArduCopter Copter 4.0
1

  1. It’s been said here a number of times to engage autotune from Alt Hold, not loiter or Pos Hold. I’m assuming that’s in reference to using autotune on it’s own switch. I’ve been using autotune flight mode. I know from how it’s drifting it’s certainly not trying to hold a location. Does it matter what mode I transition to autotune flight mode from? I’ve been transitioning form Alt Hold just to be safe but does it really matter if I’m using the autotune flight mode?

  2. After a session of autotune I was checking out the logs and the parameters and I noticed that ATC_ANG_PIT_P = 18 at the end of it. I double checked and it started at 4.5 as per the tuning guides so it wasn’t a fat-finger issue. (at least not on that value directly). The wiki says that the maximum is 12. This is an EDU-450 frame on 4S with no cameras or gimbals or toys of any kind, so I’m not expecting anything too dramatic or far off the defaults. The pitch tuning seems acceptable but it’s been hard to tell for sure because roll is a work in progress and the wind hasn’t given me a break to fix it. Should I be worried about such a high value here?

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It does. It doesn’t matter whether it’s switched with a Flight mode or a RCx option but the behavior from the the mode it’s switched from does make a difference. If it’s from Loiter or PosHold there is a “loose” hold in position while Auto Tune runs. If it’s switched from AltHold there is not and it will require manual repositioning. There have been many warning posts lately suggesting AltHold is the better method for the time being. There is a note about this in Wiki also.

Not necessarily. In my experience if the craft is setup properly, vibes are low and the frame is relatively rigid, a Angle Pitch/roll value that high can be fine. Or actually a sign that those things are good. It’s all about desired vs. actual pitch/roll.

2 Likes
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Thanks for the clarifications! I’ll keep doing what I’m doing then, and go to autotune from AltHold. I just need to find a window when the weather is more cooperative and get the roll tune all fixed up.

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The reason for not doing Autotune in Loiter is due to an issue with the way Autotune works in Loiter/ Apparently there is some bug related to Wait for Level. I can’t explain it but one of the devs indicated it is a problem.
His advice was to tune in Althold.