Loiter mode travel direction is off

Something seems to be a little off with the direction my hexacopter travels in loiter mode. I’m using an external compass/gps and have fully calibrated the compass a few times. Loiter mode seems to hold position fine, but when I move the right stick forward it often goes at an angle. It seemed fine today when I armed and held the copter facing due West, but when I turned it facing south the forward/reverse travel appeared to be off 10-20 degrees. Any ideas? Thanks

@KirkG,
How about providing either tlogs and/or data flash logs to help troubleshoot your issue. A verbal description of your issue is only the beginning.
Regards,
TCIII GM

@TCIII,

Thanks for the reply. Sorry for not including a log earlier. The only logs I had were long flights that only contained a small amount of loiter data since it wasn’t working properly. From looking at the log myself though it appears that the APM is doing what it think’s is right in that VelX and VelY are tracking DVelX and DVelY well. I’m going to do a compassmot correction this afternoon and I’ll either report back that’s it’s fixed, or have a relevent data log to share :slight_smile:. Thanks

Kirk

Attached is my latest log after doing compass_mot calibration. It seems better, but still isn’t quite right. Also, the copter seems to have sudden “wobbles” in altitude when adjusting YAW. Any ideas? Thanks

Kirk

I had a similar issue with my quad.

One thing I found is that my mag field was to high causing the direction of travel to be a few degrees off of what it was actually pointing at.

For me Loiter mode would travel more at an angle than straight.

Fix:

  1. mount GPS/Mag higher above the frames to get it away from all the interference. Mine is about 4 inches above the top frame.

  2. Make sure you have the correct declination set. What I do is get my degrees from the declination website then convert that from degrees to radians and write them in the full param list.

  3. Turn Auto dec off

http://magnetic-declination.com/