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IMU calibration (too often)

Discussion in 'Pro/Adv Discussion' started by rrmccabe, Jul 3, 2015.

  1. rrmccabe

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    I have a new P3P with maybe 20 flights on it. I have had to calibrate the IMU twice in those 20 flights and I went to take off again tonight and it was doing the "swerve" so it needs it again.

    The longest part of startup is the IMU warming up. Does not seem right as ambient is 70 degrees today.

    Anyone else having issues?
     
  2. tima4427

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    I got logged into DJI… LOL I'm getting the "Calibrate the IMU" too. at least I'm logged in now! I like the menu and set up much better than Solo. Very anxious to get this thing flying in the morning! …Once I get the IMU settled...
     
  3. Jbundy63

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    This will help you with the warm up length, also do a gimbal and stick calibration is always a good idea.
     
  4. Morphious

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    I put mine over the AC vent, battery out, battery cavity pointing down for 2 hours then calibrate IMU, works, no warm up wait time.
     
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  5. rrmccabe

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    I am sure the excessive time is probably because of not having a totally cool P3 during the last IMU calibration. Kinda forgot about the cool part and how it has to warm up to meet the temp it was calibrated at first.

    However I am concerned about the frequency. I flew my V+ over 500 miles on at most two IMU cals. The P3 has required 3 on a few flights.

    Kinda funny I got an email from a friend here in town this AM saying his P3 was acting up. His needs a IMU calibration too.
     
  6. dysan911

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    I put mine in the freezer for about 5 mins and now ever since I did the IMU calibration my warmup times are noticeably longer. Like 30-45secs. Would it be best to run it again from room temperature or maybe put it in the fridge for 10 or 15 mins this time?
     
  7. Apparition

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    I've only calibrated the IMU after the firmware updates. I've also flown several thousand miles with it and bounced it along through the airports. Warm up is about as long as it takes me to double check settings and I did nothing special except made sure it hadn't been turned on for a while before calibrating.
     
  8. dysan911

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    Well you know one thing that puzzles me about this cold imu calibration is when you pull the bird out of whatever source you used to chill it down. The first thing that seems to happen before you can press the imu calibrate button is the imu warming up. Doh!
     
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  9. 4wd

    4wd

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    Just don't forget it, I don't think 5 minutes would cool the internals much though.
    The crucial thing is to have it cooler than the anticipated conditions where you'll be flying.
    This is simply explained because the internal barometer needs to match the temperature when the calibration was done - expanding and contracting essentially.
    If your house is cooler than outside that would do it, but you need the app open ready to go the moment the phantom starts up or you'll lose the benefit.
     
  10. Morphious

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    What Firmware?
     
  11. Mark Stevens

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    I have about 6 flights on mine and I have never calibrated the IMU. I have calibrated the compass several times. I went into the app today with the intent of calibrating the IMU but when I checked it, it told me it did not need to be calibrated. Should I calibrate it anyway? I am not experiencing anything weird with the aircraft.
     
  12. rrmccabe

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    I don't mind waiting the minute it takes to do the IMU warmup. That is fine. I just don't like lifting off and having a Phantom veering off to one side or another and stopping to find a level surface to do a IMU cal. Not always easy to make a level table on the go to do a calibration.

    1.2.6
     
  13. rrmccabe

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    That check IMU has little value. Mine always checks OK but its obvious when the aircraft needs an IMU cal and is fixed when its complete.
     
  14. SouthernPhantom

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    Before IMU calibration, I place my P3 in the refrigerator with no battery (usually in a plastic bag to avoid condensation) for 35 minutes. Always works great. No warm up time at all when flying. Occasional calibrations help performance, even if it says no calibration is necessary. There are always landing and travel bumps over time. But remember, when the drone comes out of the fridge, it will say "warming up". Ignore that message. Go right to the calibration and do it! Then center the camera, and re-calibrate the gimbal! Smooth flying!
     
  15. brushlesheaven

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    Guys, when you get in to IMU calibration, how long is the process?
     
  16. Mark Stevens

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    thank you, that is good to know.
     
  17. SouthernPhantom

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    It takes just a few minutes. Wait for the confirmation message after the bar reaches 100%. Meant to mention earlier, make sure it's done on dead-level surface as determined by a carpenter's level. And don't bump into anything or even walk heavily nearby while it's calibrating.
     
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  18. brushlesheaven

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    Forgive me if I am wrong but if it takes few minutes than it will have enough time to worm up to its own working temperature before the calibration is done. Why cool it down before the process? I was hoping the calibration process will be done in like seconds before the system reaches its own designated working temperature...
     
  19. SouthernPhantom

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  20. SnoozeDoggyDog

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    TX on, phone connected, Pilot app started.

    Start the car, Battery out, gaping hole against air con vent, lowest temp, highest fan, hold it there for 5 mins.

    After 5 mins turn off the car, insert battery, jog, shuffle, walk run (dependant on age!) to the Tx, switch on bird when on a LEVEL surface ..... You know the rest.
     
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