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Any Ideas? New Phantom 3 hovers in circles

Discussion in 'Pro/Adv Discussion' started by CaptainDrone798, May 30, 2016.

  1. CaptainDrone798

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    I received a replacement Phantom 3 Professional from DJI China (drone only). I did the binding thing to my RC. Upgraded the firmware to version 1.08. Did the compass calibration.

    Took it out for a test flight. Brought it to a 3 foot hover and it began to drift to the right, and then faster so brought it down quick and it tipped over.

    Put it on my concrete basement floor and ran the IMU Calibration. Went back outside, redid the compass calibration. Took off to a hover of 3 feet. It seems to hover for a second, then drop 6 inchs. Then it begins to drift as if it's tracing the outline of a circle. Small at first but the circle increases. Bringing it down while it's moving of course causes it to tip over.

    Any thoughts on what the issue could be?
     
  2. Oso

    Oso

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    I would normally say compass cal, but if you are sure you've done a good compass calibration in a good area, then perhaps you need to do an RC calibration.
     
    #2 Oso, May 30, 2016
    Last edited: May 30, 2016
  3. flpholt

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    perhaps there is metal in concrete where you did your imu
     
  4. Multicoptertec

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    Where did you calibrate the compass? Inside? Outside? Near any metal, etc?
     
  5. flpholt

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    he did it on concrete basement floor
     
  6. Mako79

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    IMU isn't affected by metal.
    Just to clarify:
    IMU - Phantom needs to be cold and on flat surface. You can do this indoors.
    Compass - in an open grassy field. You can do this outdoors.

    You are getting TBE (toilet bowl effect). Redo your compass dance in an open field.
     
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  7. flpholt

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    your wrong there metal will affect a imu
     
  8. Oso

    Oso

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    He did the IMU on the basement floor which is fine. He went outside to do the compass calibration. @CaptainDrone798 is not a newbie. I have confidence he knows where to do a good compass calibration.
     
  9. flpholt

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    but some concrete floors are full of metal which would affect the imu
     
  10. Oso

    Oso

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    hms likes this.
  11. CaptainDrone798

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    Outside, same place I've calibrated the compass on other drones. The location has not been an issue in the past.
     
  12. CaptainDrone798

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    Never had that happen before with other Phantoms. Will try a large open field tomorrow for compass calibration.
     
  13. Mako79

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    Ahh.. No.
    The IMU has gyro and accelerometer and barometric sensors which none will be affected by magnetic influences.
     
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  14. nix240z

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    I did a IMU calibration on a level tile floor and got a bad Imu calibration with numbers out of range. There was an metal air duct right under the tile floor, which was causing the high range of numbers.... moved a few feet away and all good.
     
  15. Oso

    Oso

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    Thats awesome, but IMU doesn't care about metal.
     
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  16. nix240z

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  17. HWCM

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    He is right. There is nothing in the IMU to detect or care about metal or the influence of metal. It just wants flat and level. You could do it on the steel structure of a skyscraper if you wanted to, as long as it is flat and level.
     
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  18. HWCM

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    Do it a couple more times in a row. If it still acts wonky, you may have a bad compass or the compass orientation is not correct. The compass physically needs to face magnetic north. I have seen compass chips on builds I have done where the compass was put on backwards to the way it was supposed to be. But usually this will cause the quad to quickly shoot off in a random direction and keep going.
     
  19. CaptainDrone798

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    Thanks buds!
     
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  20. CaptainDrone798

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    Since I'm perplexed by this, I'm now grasping at straws.... So, I downloaded the new DJI GO App (the one released today), placed the Phantom on a wooden table, levelled it to perfection, redid the IMU calibration & the results came out spot on (zeros across the top line). Tomorrow I'll take it to a larger field (larger than my backyard) and calibrate the compass. If it still flys toilet bowl wonky after all that, then I've got a defective unit.
     
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