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IMU Calibration - Is This Level Enough

Discussion in 'Pro/Adv Discussion' started by bobomet, Mar 25, 2016.

  1. bobomet

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    This is as close as I can seem to get with a level surface for my IMU and Gimbal calibrations.
    Do you think this is good enough?
    [​IMG]
     

    Attached Files:

  2. msinger

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    Why not just put a few sheets of paper under the landing gear to get it completely level? Or, better yet, under your table -- or whatever you're using.
     
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  3. flyNfrank

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    ....nope not good enough.
     
  4. alokbhargava

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    I think you can do better leveling before you start IMU calibration.

    Another point: 8" or 12" longer surface leveling devices may be better for P3 as they would measure over a wider surface area. You would get more accurate results and you should check leveling not just at one point.
     
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  5. Monte55

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    Not all bubble vials are accurate. I found that out many years ago. Where are you putting the level? On the quad or the surface its sitting on? Im not sure you have to level to a knats *** with level. One has to wonder if the unit in the quad is at the same level as it sits on the landing gear. When at the field, do people starting actually level their quad so precisely? . Im sure the IMU CALIBRATION being level is more important than at power up at field. Not sure.. Im not sure what all goes on with gyros at start up. I try to have mine as level as possible at start up but sure its not perfect. People that have to launch on unlevel ground or hand launch...what are your results?
     
  6. Reed L

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    Nope, not good enough and also you need to use a better level. Those are cheap levels for getting a trailer sorta level. You need a good accurate level to begin with. I have an old cast iron level from my grandpa but there's lots of options. Plastic won't do it.
    Kapro 930-16 Smartcast Aluminum Professional Mason's Level with Optivision Red Vial, 0.0005 in/in Accuracy, 16" Length x 2.2" Height: Precision Measurement Products: Amazon.com: Industrial & Scientific

    Mounted Tubular Levels, Geier & Bluhm
     
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  7. msinger

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    Why not?
     
  8. Reed L

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    That particular level he has can be flexed. You want to look at the size of the bubble and the width of the marks on the bubble, the longer the bubble tube, the better. In his level, the bubble isn't an exact fit between the lines, it's designed for minimal accuracy and will warp and flex in the sun. Basically you guess where it's level with that one if that's the 2" x 2", the level should be either mounted or long enough to span the width between the legs of the UAV.
     
  9. msinger

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    Makes sense. It sounded like you were saying all plastic levels should not be trusted.
     
  10. Quadcopterpilot

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    I'm not saying this is right but I just put the bird on my basement floor, never checked the level, did the calibrations and I have over 50 flights with no issues and perfect video. Just saying.
     
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  11. 4wd

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    Like almost everyone else!
    There was a period when the Vision Plus had wonky gimbal issues and a temporary *fix* was to deliberately do the IMU on an angle to counteract the gimbal tilt.
    In other words it's not crucial but if you don't have it more or less level it will fly on a slight angle and you might notice some resulting issues. .
    In any case the levelling should be done diagonally on the motor hubs not where you place it - because the legs could easily be less than perfect.
     
  12. Monte55

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    Not sure I would want to do calibrations on a basement floor which is most likely concrete and has rebar in it.
     
  13. msinger

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    How does rebar negatively affect an IMU calibration?
     
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  14. Shammyh

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    It doesn't.
     
  15. msinger

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    I know ;)
     
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  16. Monte55

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    Not sure if it would...that's why I said "not sure" in my post.I wouldn't do it when there are so many other options.
     
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  17. Shammyh

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    I knew you know. :)

    But it's hard to resist snappy one liners...
     
  18. Monte55

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    I just read calibrations. . Imu was not specified that I saw. .
     
  19. msinger

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    No worries. The OP is talking about an IMU calibration.
     
  20. Ed209

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    I found my kitchen island to be perfectly level. I always place my P3s on that when doing an IMU calibration. Haven't had any issues.