Re: Oscillation in GPS Modes that is Sensitive to Compass Direction
« Reply #30 on: December 18, 2015, 05:49:19 pm »
What type of PDB are you guys using?  This is the one I am using.  It is on the bottom side of the bottom plate and my FC and mag are a about 2cm and 3.5cm above the top board.

« Last Edit: December 18, 2015, 05:53:23 pm by TheOtherCliff »

Re: Oscillation in GPS Modes that is Sensitive to Compass Direction
« Reply #31 on: December 18, 2015, 06:16:05 pm »
Any of you guys tried a camera gimbal?  It would be informative to know if a gimbal makes it better or not.

(If it makes it better, the problem is probably a simple oscillation because the attitude estimation is correct.  If not, it is more probable that the attitude estimation is wrong or part of the oscillation chain (or gimbal isn't fast enough to correct the tremor)).

Re: Oscillation in GPS Modes that is Sensitive to Compass Direction
« Reply #32 on: December 18, 2015, 07:01:15 pm »
I wonder it it would help to tune PIDs in VelocityRoam mode rather than Attitude mode.  Maybe tune pointed in bad direction.

I forget now.  Is one of you guys the one that posted about this back in the OP days?  There was a really good video with just yawing that was clearly an issue when pointed in different compass directions from that time period.  Does that copter still exist in that state or has something been done to it and now it isn't quite so bad?

Maybe we need to try to make it worse rather than better.  I will try to make a loop in one PDB -> ESC that points in a calculated direction.  When that motor is pointing north, it should fly fine, but when pointing elsewhere there should be problems.

lanzi

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Re: Oscillation in GPS Modes that is Sensitive to Compass Direction
« Reply #33 on: December 18, 2015, 07:14:52 pm »
Yes I am the one who posted about this issue back in OP forum and I also posted the yawing video. Yes that quad still exists.

f5soh

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Re: Oscillation in GPS Modes that is Sensitive to Compass Direction
« Reply #34 on: December 18, 2015, 11:12:28 pm »
@lanzi If i remember you live in NZ ?
Can you check if mag readings on PFD matches the geographical North ?

Re: Oscillation in GPS Modes that is Sensitive to Compass Direction
« Reply #35 on: December 19, 2015, 06:48:43 am »
Laurent raises the question of magnetic declination (a different thing than the mag inclination I was testing with setting HomeLocation way north or south) too.

If someone that has the issue that uses aux mag sensor only (OP GPS V9/Platinum with AuxMagSettings.Usage=AuxOnly) could adjust their aux mag yaw by say +-5 +-15 +-45 degrees until they see a change in the + and - directions we could see if that helps the issue.  Of course I can try the opposite: make it worse the same way.

Aux mag yaw is set at AuxMagSettings.Orientation for 15.09 and at AuxMagSettings.BoardRotation.Yaw for next.

If everyone here that has the issue could report back the country they are in we can see if there is a common theme in location.

lanzi

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Re: Oscillation in GPS Modes that is Sensitive to Compass Direction
« Reply #36 on: December 19, 2015, 07:25:16 am »
This makes a lot of sense. I hate to mention it but back when I was using naza here in NZ I had to rotate the GPS PUC by 15 degrees clockwise to make it work and to avoid toilet bowl . I will give that's trybasap and report back.

liftbag

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Re: Oscillation in GPS Modes that is Sensitive to Compass Direction
« Reply #37 on: December 19, 2015, 04:50:46 pm »
Hi all. Late in the party  :D

I think I was among the first to discover this issue since the times of OpenPilot.

My issue was present even in motion and was only N/S related.

Here the video.


Re: Oscillation in GPS Modes that is Sensitive to Compass Direction
« Reply #38 on: December 19, 2015, 08:55:40 pm »
That's the video I remember.
Very clear pitch oscillation pointed north.  Smaller pitch oscillation pointed south.  None when pointed east/west.
That was in Italy correct?

liftbag

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Re: Oscillation in GPS Modes that is Sensitive to Compass Direction
« Reply #39 on: December 19, 2015, 10:36:37 pm »

That's the video I remember.
Very clear pitch oscillation pointed north.  Smaller pitch oscillation pointed south.  None when pointed east/west.
That was in Italy correct?
Yes, La Spezia Italy

lanzi

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Re: Oscillation in GPS Modes that is Sensitive to Compass Direction
« Reply #40 on: January 06, 2016, 11:59:02 pm »
happy new year everyone.

did some extensive testing over the holidays trying to eliminate these pesky oscillations in gps flight modes.
i am out of ideas by now. tried offsetting the compass rotation value to compensate compass declination.
had absolutely no effect on the oscillations other than i got toiletbowling with values higher than -20 degrees.

also thought i got a solution by keeping the KP values of VelocityRoamHorizontalPID, BreakHorizontalVelocityPID and HorizontalVelocityPID at the same value.

but also that did not work.

i really hope the defs can fiind what is causing this bug, because these oscillations make the entire GPS functionality worthless when it comes to UAV videography.
and that really would be sad.

Re: Oscillation in GPS Modes that is Sensitive to Compass Direction
« Reply #41 on: January 09, 2016, 01:28:02 am »
Thanks for trying anyway.   :'(

Wagsy

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Re: Oscillation in GPS Modes that is Sensitive to Compass Direction
« Reply #42 on: January 09, 2016, 03:11:38 am »
Hey Lanzi, well done on trying all those variables.
I have not flown mine for some time, but I only need it for RTH if I loose video signal, so the small oscillations are no probs.
But it would be good to nail it down.

gitit20

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Re: Oscillation in GPS Modes that is Sensitive to Compass Direction
« Reply #43 on: January 15, 2016, 07:03:02 am »
I've also tried all this and still can't get it to work. I'm lost now lol. I hope they figure it out soon. Have you seen my YouTube video? Of how good it worked with 14.xx?
Do the best you can It's all you can do.

lanzi

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Re: Oscillation in GPS Modes that is Sensitive to Compass Direction
« Reply #44 on: January 15, 2016, 07:13:33 am »
hi gitit20,

yes i hope this will be resolve. i know for sure that it worked perfectly until 15.02. that was also the last version where before velocity roam was introduced and the last version where VtolSelfTuningStats populated in GPS assist.

I believe this is all tied together somehow.

yes i have seen your video