Replies to This Discussion

Permalink Reply by Vincent Mees on May 11, 2011 at 12:12pm

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. 

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AdminPermalink Reply by John C. on May 11, 2011 at 12:26pm

Did you guys set your declination?

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Permalink Reply by Vincent Mees on May 11, 2011 at 12:39pm

yeps, mines -0,5

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Permalink Reply by Nigel on May 11, 2011 at 2:12pm

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.)

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Permalink Reply by Vincent Mees on May 11, 2011 at 2:32pm

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? 

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ModeratorPermalink Reply by John Church on May 11, 2011 at 2:52pm

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.

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Permalink Reply by Nigel on May 11, 2011 at 3:39pm

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?

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Permalink Reply by Al Ros on May 11, 2011 at 9:31pm

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

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DeveloperPermalink Reply by jasonshort on May 16, 2011 at 10:10pm

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

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Permalink Reply by Al Ros on May 16, 2011 at 10:15pm

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

Al

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Permalink Reply by Russell B. Sutton on May 11, 2011 at 4:29pm

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.     

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Permalink Reply by Russell B. Sutton on May 11, 2011 at 5:07pm

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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