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Phantom drifting again - what am I doing wrong?

Discussion in 'Phantom 2 Discussion' started by tferrari, Aug 14, 2014.

  1. tferrari

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    First off I'm in a 15 degree declination location.

    This is my second P2. I lost the first one in a swamp because of stability issues (I yawed, it looked like it had a VRS issue but plummeted from 30 feet and landed upside down). I've only had this new P2 for a day or so and it seems to be showing the same issues as the first one I purchased. I'm scared to take the thing more than 10 feet off of the ground now.

    When I yaw the P2, this is when the unit tends to drift significantly to one side or the other. I would say that yawing is the most likely maneuver to create drifting issues.

    Things completed to date:
    Updated to latest firmware (3.06)
    Performed controller calibration in RC assistant and P2 assistant.
    Performed advanced IMU calibration 2-3 times with values showing in the correct range. This is performed in my residential house one with P2 1 foot off of the floor with all hardware installed (transmitter, wires etc).
    Compass dance 4 or 5 times in a reasonably magnetic interference-free area with correct light sequence. Sometimes it has failed but if I repeat it, it accepts the compass dance.

    Things not completed to date:
    Compass degaussing as the values after advanced calibration look ok.
    Compass dance miles away from anywhere in a farmers field
    Advanced calibration in a location other than my house.

    Other information:
    iOSD shows 7-9 satellites before I take off and I see no issues with these satellites dropping or anything during flight
    Azimuth data on iOSD seems to be incorrect
    The 'diamond' shown by iOSD does accurately point to home position (or so it seems)
    Issue doesn't seem to appear in ATTI mode.

    Specific questions:
    Can the compass need degaussing even if the advanced calibration shows the values to be ok?
    Are there any checks I can do to actually verify the quality of an advanced calibration?
    How important is it that your compass calibration be completed in the middle of nowhere? If the compass is extremely sensitive to magnetic interference during calibration, then why wouldn't it be equally sensitive during flight? It doesn't make sense that the unit has to be calibrated when absolutely nothing is around because eventually you'll fly it in an area that has large metal objects like a car, a train car or a residential power line...
    Is there any value in doing advanced calibration when not inside of a house?

    I'm starting to lose my mind here... how can I be having issues with two completely different phantoms!? What am I doing wrong...?
     
  2. CarlJ

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    If you're having an issue with the compass in general the software will report it. An exception to this would be compass orientation which would not be reported by the software. The compass is very picky about it's orientation, and if you've upgraded your landing gear and had to remount your compass this could be your issue.

    You've said that your compass values are normal, but could you post the values for us so we can rule that out?
     
  3. tferrari

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    The raw compass value is typically 1280-1295. I am not at my computer at the moment so I can't check the rest of the values.
     
  4. hrosee

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    You didn't say anything about adjusting the gains. I had to up the Yaw to 250 and the roll and the pitch to 175. Solid as a rock now. Give that a try. It's no big deal it you go too high. It will just shake a little bit and the motor kind of oscillate a little. Just lower it from there and you are good to go.

    A lot of people don't seem to understand what the gains are for. They will correct the problem you are having.
     
  5. damoncooper

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    Interesting. Might be worth trying. I also have drift on yaw.
     
  6. GerdS

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  7. UrAwFuL

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    How high was the Phantom when it's drifting?

    Was it windy?
     
  8. tferrari

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    Gains!

    I can't believe that something as simple as adjusting the gains has transformed this Phantom 2 from, essentially, a piece of a junk to an absolute flying monster. It's almost rock solid and I can spin in yaw without any drift or instability. I can max out the sticks in any direction when flying and I don't fear an uncontrolled descent.

    I'm at Basic: 170/170/190/195 Attitude: 150/150 and it feels right for me. I'll likely tweak these as I start doing different things with my phantom, but this ok for now. I think I could improve it a little, but it's cumbersome having to bring the unit back inside, plug it in and update the gains over and over. I wish I could adjust these on the fly...

    Someone really needs to write a sticky on gains as I think this may be the solution to problems that some of the community users are having.

    Thanks all!
     
  9. OI Photography

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    It's good that the gains helped stabilize things for you, but if those are still your compass mod values you'll probably still want to do the degauss process. Ideal values for that are in the 1600-1800 range.
     
  10. badbrad97

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    I agree about the sticky for this. I took me forever to figure this one out too
     
  11. tferrari

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    I have the compass around 1680-1700 after degaussing it again. Thanks for the suggestion.