Hi Folks

 

I am really having a problem with my yaw stability and I am hoping someone can point me in the right direction.

1st if compass is diabled in either Arducopter 2.x or ardupirates code. I have excellent yaw control just like on my mikrokopter.

If I enable compass at default PID settings, yaw hold is very sloppy (better at default values for arducopter 2.x) . for example in ardupirates code I have to increase P and D to 7.5 and 3.5 otherwise it keeps rotating past when I let go of the stick. But at these high PID values yaw is not smooth and hunts (not really oscillates) and the hunting affects roll and pitch stability

 

My Yaw gyro must be ok since without compass yaw is great. My compass heading seems ok and is relatively steady. but my issue is now with two different codes.

 

Is this a bad compass, or is this what other folks are seeing as well? if anyone was able to correct sloppy yaw - how did you do it.

 

Roll and pitch sabilization are perfect by the way

Thanks

Al

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Just started out flying after I got xbee working.

I'm having the same issue.

With mag disabled I have a steady yaw. And boy when you stop rotating the quad stand directly still in that direction. Its almost like a tank turret ;-)

When I enable mag the quad yaws to the left when going forward and right when going backwards.

I've been playing around with the yaw pids but can't really see any difference.

Is this a PID setting or should I look elsewhere.

 

The quad flew very good with ardupirate code. 

Did you guys set your declination?
yeps, mines -0,5

I have a similar issue although I have not tried disabling the compass yet.  At the moment I am doing most of my flying in Stabilize Mode and I find that if the heli is pointing say North and I use the rudder control to rotate it round to point say North West, it will swing back to North again.  If I am persistent and move it round to say West (i.e. further round) it will go back to about North West.  Being a heli pilot and used to heading-hold giros, this seems a bit strange.  As soon as the demand for yaw from the pilot had ceased I would have expected the quad to stay pointing where it was.  I have not tried adjusting any yaw PID values.  I am in London using a declination of -1.56.

(I'm using the latest (as at this morning) AC2 beta code on a 1280 board.)

Maybe something I haven't mentioned.

I'm using the the sparkfun mag but haven't defined orientation.

This has probably nothing to do with it? 

Hey guys,

Have you taken out a "real" compass and started the compass test via CLI to verify that what your quad thinks is North is really North? I am in a region of positive declination, but didn't get it working right until I entered it as a negative value.

Now North is North.
Unless you are flying a mission where the compass presumably has a direct influence over your incremental GPS position, does the accuracy of the compass really make much difference?

Nigel

 

your statement seems logical. since I am not at the stage of testing position hold or waypoint navigation yet, I don't really care where it thinks its pointing, I just want my yaw to be as clean and crisp as it is with with compass off !! one would think that for just normal flying if the compass is off by 10 degrees it should not matter to yaw hold. 

Regardless, I have set my declination as per instructions and the compass points pretty well exactly at north.

I am thinking of ordering another compass just to see if it is a hardware issue. The yaw hold does improve a bit with rasing yaw p values to an extent, then worsens again

Al

If the compass is upside-down you can have inverted results in flight while in Stable mode.

definitely not inverted. I get correct heading. Actually for me latest firmware has corrected much of the yaw drift

Al

I have the same problem and saw this the first day AC2 was released.  My Declination is 14.5, this causes a 20 deg. to the left  defference from my compass.  APM pointing @ 340 deg.   Using -6 as my declination seems to line up with my colemen camping compass.  This compass thing is very tricky because we have many different "a like" terms,  True North an Indicated North.  I think maybe an ERROR in the declination Equation is causing an issue.     

I just tried using 0 for my Declination and my APM is right.  It's pointing perfectly north with my colemen camping compass.

what is this about?

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