Loiter Spiral

when I start a loiter it hold for a few seconds then starts to spiral bigger and bigger circles.

Ideas?

Forgive me if I’m wrong, but isn’t that caused by a bad compass calibration?

Yes, this is pretty much always caused by compass problems. Most of the time it’s because of interference from the power wires or power distribution board. You should probably try giving compassmot a try and see what perctage interference it’s producing.

Interference at full throttle is 5% of mag field…

Mag Dec: 0.000
MAg off: -8.5619, 280.5477, -166.3902
Motor Comp: current
Comp Vec: 0.53, 0.31, -0.55

dec is 0 is this correct?

Check if your board is perfect aligned with the frame.

Why GPS glitch is not trying to compensate those spirals? I know the reason GPS glitch was introduced, but since in loiter we want fix coordinates, why GPS glitch function is not able to do this and keep the copter inside the radius, supposing GPSGLITCH_RADIUS is 200 (2m). Each values outside of defined radius should be considered glitches and then this should be corrected.

OHH one more thing. I did NOT do that compass test with props ON I took them off will that skew the results? if so I will re-do.

I would upload the flight logs but it says that the forum quota is full and I cannot

[quote=“dpackham”]OHH one more thing. I did NOT do that compass test with props ON I took them off will that skew the results? if so I will re-do.

I would upload the flight logs but it says that the forum quota is full and I cannot[/quote]

You need to do it with props on, but be careful :slight_smile:. Without the props the motors won;t draw anywhere near the same current, and its the current that affects the compass.

I have seen some people fit the opposite props on so that it pushes into the floor.

That is how you should do it. Move all props one position further and turn them upside down.

ok will do.

with props :slight_smile:

Interference at full throttle is 23% of mag field…

Mag Dec: 0.000
MAg off: -8.5619, 280.5477, -166.3902
Motor Comp: current
Comp Vec: 1.44, 0.81, -3.21

Still a problem?

Here is the log of that flight. you will see a few times that I turn on loiter and the spirals that it made.

Sorry this log file is from “default” mode without the IMU… so i dont know if it will have what you need to see

according to this page less than 30% is ok

copter.ardupilot.com/wiki/ac_com … ESC_motors

But it doesn’t hurt to try and reduce it further if its simple to do.

Stu

[quote=“dpackham”]Mag Dec: 0.000
MAg off: -8.5619, 280.5477, -166.3902[/quote]
Unless you live right on top of the North Pole, your declination is not zero. Either activate automatic declination or set the appropriate value manually.
Your offset values are massive. They shouldn’t exceed +/-150. Reposition your APM or - better - use an external compass.

ok. this is a DJI style frame so I cant move it too far and the battery is right underneath the FC.

I was using auto declination when i made that log. i have since switched to inputting my own coord’s

remote mag I need to get one and try that. any links to one I can hang on the GPS pedestal?

what would cause those offsets to be so high? proximity to power? EMI?

ok dec set and net logs with IMU logging. acc-z looks a bit big I think?

but it still spirals on loiter