Very bad Loiter, how to "debug" aka analyze situation?

Hi !
I have a small Hexa that now flies very sharp after some tuning.
(3.2.1 APM using NEO 8 GPS/MAG)
In Stabilize and Alt-Hold it behaves REALLY good (i am at the highes limits for PID so its razor sharp, i may reduce that for FPV).

The Problem is, it really starts to go haywire when entering Loiter…
–> It flies away in a random direction until i enter Alt-Hold and bring it back.
If i have wide open space it MIGHT is a very wide toilet bowl as it seems to goes in an arc.

I checked the logs, GPS Position is acurate (from map plot), Sats starting with 7 going to 10 soon with HDOP < 1.5 .

Compass is very accurate on the Ground and compassmot reported that it had very small interference before and virtually no interference after compassmot.

I tried “simple” mode and can do UFO-style flying (rotating while going in one direction) pretty okay.
So i guess the compass is also okay in flight (i do not seem to find a “compass-heading” in any of the log options).

I only know toilet bowl or any problems at all from cases where the compass heading was bad due to bad calibration OR heavy motor interference, this does not seem to be the case here.
Could you give me a hint how to get hold of this problem ?
(What to log, where to look at or what to post here ?)

The obvious answer would be to log “nearly all” but if i do that the log file is not okay, maybe thats a 3.2.1 problem ?

I went back to 3.1.5 but it exhibits the same Loiter Problem…

In other words:

HEEEEEEELP me, please :slight_smile:



Hi !
Well as there was no hint here what to log / look at i simply put up one of my latest log files here.
Maybe someone can look into it or has an idea what to log / look at to get me on the right track.
See in the log that i switch to loiter and very quickly have to switch back to alt-hold as the Hexa tries to fly away.



Hi, enderffx!

Were you able to solve the problem?
I have a similar situation. I fly the 450 helicopter.
But in your logs I noticed the GPS error. Note
the vanishing of the coordinates you had, just in the second turn on LOITER.
I have a similar problem, but M8N gives a lovely coordinate.
I guess at the presence of closely spaced metal objects:
the tail boom mount and servo. Although the interference is not very large
on main external compass.
Do yourself what action you set failsafe on GPS, because
that copter looks like you have flies on this action.

P.S. Sorry for my English.