Welcome to PhantomPilots.com

Sign up for a weekly email of the latest drone news & information

IMU Calibration Warm Up & Gimbal Horizon Issues, a must watch video

Discussion in 'Pro/Adv Discussion' started by Hovtech, Jun 14, 2015.

  1. Hovtech

    Joined:
    Mar 27, 2014
    Messages:
    502
    Likes Received:
    151
    If you have a new Phantom 3 and you are not an expert, this video is the most important 7 minutes you can watch. It will prevent a lot of problems. If you don't watch all of it and end up losing your Phantom, it was because you didn't watch this.



    [Moderator edit: Thread title changed. Clickbait titles are awful. :p]
     
    #1 Hovtech, Jun 14, 2015
    Last edited by a moderator: Jun 15, 2015
    bobomet, Fjallis, Pumpfixer and 5 others like this.
  2. dirkclod

    dirkclod Moderator
    Staff Member

    Joined:
    May 9, 2014
    Messages:
    10,680
    Likes Received:
    5,712
    Location:
    Amory Mississippi
    Interesting ..is the way I do my P2 but with glass on top to be sure it's level .
    Thanks for sharing that bro ! :cool:
     
  3. BrewserB

    Joined:
    Oct 27, 2013
    Messages:
    159
    Likes Received:
    16
    Location:
    Colorado
    It's weird but since I switched to an iPad from an Android tablet and did an IMU calibration it now takes about a min or two for the IMU to warm up. I was able to fly in a few seconds before.
     
    Ari likes this.
  4. shapechange

    Joined:
    Jun 14, 2015
    Messages:
    8
    Likes Received:
    2
    I tried doing this and even tried his gimbal calibration mid-flight trick and still don't have a level horizon. Any one else found a fix?
     
  5. Phantom751874

    Joined:
    Mar 13, 2015
    Messages:
    995
    Likes Received:
    269

    Everything I have read is to try it a few times. Absolutely make sure you are on a level surface and the craft is cold.

    I am having the same issue and tried this 3 times without luck. I stuck mine in the fridge for 15min and it hasn't hurt anything. I'll be sending my P3P back to DJi as a result. This is the guidance that Blade and Tahoe have given and they have said DJi knows about the issue and is continuing to look into it. But DJi hasn't said whether or not this is a hardware of firmware (software) issue. Maybe they don't know.

    I have a P3A as well and it has never had this issue. And the first thing I did after I opened it was a cold (fridge) IMU then immediate gimbal calibration on the P3A.
     
  6. shapechange

    Joined:
    Jun 14, 2015
    Messages:
    8
    Likes Received:
    2
    thanks for sharing that. I will try again. Does it matter that I've had my phantom for a few weeks if I want to return it to get it fixed? What's the process you followed for DJI? Btw.. appreciate your input mate.
     
  7. Phantom751874

    Joined:
    Mar 13, 2015
    Messages:
    995
    Likes Received:
    269
    I haven't contacted DJi yet. I may hit their website and start a chat with them as technical support is 24/7 for the P3 right now. I have chatted with them before about other issues and they usually jump on pretty quick but it seems as though they handle multiple chat sessions at the same time. I have waited up to 5 minutes before they answer back and I've had them answer back and forget what we were chatting about. It can be pretty frustrating.

    The other option is to call them but I haven't done that before. But I have read of excessive wait times with some reporting up to an hour and a half wait before getting someone on the phone. I will likely go this route however and hope for a shorter wait time. It's better to have someone's undevided attention I think when trying to line up a return for warranty work.

    Also, insist that they pay for shipping both ways. Others have mentioned here they won't offer it by default but if you insist politely they will.
     
  8. tcope

    Joined:
    Jan 29, 2015
    Messages:
    3,552
    Likes Received:
    1,396
    Location:
    Salt Lake City, UT
    I'll mention what I did that has helped me. I'm not saying that this will work for everyone or that it's an absolute solution. I calibrated the P3's IMU as mentioned. My camera was tilting slightly. I then propped up one side of the landing gear to compensate for this tilt and did the camera calibration. I had to do this a few times to get the correct height on one side but eventually it's almost completely corrected the tilt of the camera. I've powered the P3 on and off several times and it's not changed.
     
  9. IflyinWY

    Joined:
    Sep 12, 2014
    Messages:
    3,470
    Likes Received:
    939
    Location:
    Where the deer and the antelope play
    Hmm, interesting suggestion by the OP.
    Could it really be that the IMU likes a controlled environment (Cold, Stationary, and Level) in order to calibrate properly?

    I agree with the fact, it might not work for some, but now you know how to do it properly.

    And like Dirkclod says, a sheet of glass over the motor shafts should ensure your IMU is as level as you can get it.

    Thanks Hovtech, good job.
     
    dirkclod likes this.
  10. ianwood

    ianwood Taco Wrangler
    Staff Member

    Joined:
    Jan 7, 2014
    Messages:
    4,930
    Likes Received:
    1,801
    Location:
    Lost Angeles
    "As cold as possible" is a little misleading. Though the advice to leave it in a cool place for a little while is good. Do not stick it in the fridge unless you plan to fly in wintery weather. Ideally, you want the IMU to be a few degrees colder than when you will be using it.

    The reason being is that DJI uses a "ramp" calibration method that measures scale and bias values at different temperatures. The IMU "warms up" naturally as soon as it is powered up. So as long as the IMU is a little cooler when you start calibration than when you fly, it should be good to go pretty quickly.

    Perfectly level and absolutely no external vibration are also very important.
     
    dirkclod likes this.
  11. dirkclod

    dirkclod Moderator
    Staff Member

    Joined:
    May 9, 2014
    Messages:
    10,680
    Likes Received:
    5,712
    Location:
    Amory Mississippi
    In my mind and from testing if you have just a little imperfection in one skid I don't care how level the table is your bird won't be ! Why I use the glass over my motors and level from there . Just me but it works and have tried everyway to do the leveling .
    As far as the cold thing I don't know but have just considered cold as haven't cut it on in several hours .. Ya learn something new everyday huh !
     
    tcope likes this.
  12. Kevin H.

    Joined:
    Jun 15, 2015
    Messages:
    61
    Likes Received:
    10
    Dirkclod,

    I have a P3 Advanced and am interested in your "Glass" method. Could you provide a few more details on what exactly this method entails.

    Thanks!

    Kevin H.
     
    RyanK likes this.
  13. dirkclod

    dirkclod Moderator
    Staff Member

    Joined:
    May 9, 2014
    Messages:
    10,680
    Likes Received:
    5,712
    Location:
    Amory Mississippi
    Glad to Kevin and just all of what I did is in this thread http://www.phantompilots.com/viewtopic.php?f=19&t=35131
    I was trying everything I had read about getting the quad level before doing an Advan.IMU Cal. Well what's really level ? Maybe the table but if a skid not perfect with the other then you not level. Tried doing it by taking the top off and leveling the naza and then tried placing a piece of glass over all 4 motor shafts and using a little bubble level and just using playing cards for shims to get it perfect then doing the Cal.
    Was really just testing all I had read about folks had done before me and I just settled on the glass as it was the easiest to do and worked the
    best for mine . Just because you on a level surface don't mean the naza is and just because the naza is level don't mean all the motors are
    level.
    In my mind and those that know me here know it's simple in the end what is level is the props when in a hover . That's level so I just do my Advan. C that way and it fly's great .Read what I showed ya and ya see some smart folks explain it a lot more teckie than I can .
    Sorry this sounds strange but so am I and don't know any way else to put it .
    I hope this helps ya understand where I am coming from !
    I think I just confused myself :eek:
     
    IflyinWY likes this.
  14. CYeutter

    Joined:
    Aug 6, 2014
    Messages:
    49
    Likes Received:
    10
    Something else to consider before doing an IMU calibration. There's a chance the calibration may diminish your ability to yaw in place and may require a fair amount of trial and error to get it back.
    See this thread from the P2V+ forum. http://forum.dji.com/forum.php?mod=viewthread&tid=4343&page=1
    I'm not saying don't do the calibration but if you are not experiencing any issues you should be aware of something that might be introduced by doing it.
     
  15. dirkclod

    dirkclod Moderator
    Staff Member

    Joined:
    May 9, 2014
    Messages:
    10,680
    Likes Received:
    5,712
    Location:
    Amory Mississippi
    The way I did it fixed my yaw issue so maybe that guy didn't have it level . Just saying'
    I agree if it ain't broke don't mess with it but just sharing what I found to work for me .
     
  16. tcope

    Joined:
    Jan 29, 2015
    Messages:
    3,552
    Likes Received:
    1,396
    Location:
    Salt Lake City, UT
    This way is best but you could also flip the P3 upside down onto the motor spindles and place a level on the VPS unit.
     
  17. Oso

    Oso

    Joined:
    May 19, 2015
    Messages:
    2,539
    Likes Received:
    1,486
    Location:
    Sacramento CA
    Thanks for posting this. I have been thinking of doing exactly what you described. It seemed to me that this would work, but I just haven't gotten to it yet. Now based on your post I am even more confident in this fix.
     
  18. gfredrone

    Joined:
    Jan 24, 2014
    Messages:
    1,221
    Likes Received:
    191
    I use the glass on top of motors method as well. Not sure on doing it upside down??? The gimbal might freak out and the IMU values could get reversed.

    Edit: Just noticed this was my 1,000th post!
     
    #18 gfredrone, Jun 15, 2015
    Last edited: Jun 15, 2015
    IflyinWY and dirkclod like this.
  19. Kevin H.

    Joined:
    Jun 15, 2015
    Messages:
    61
    Likes Received:
    10
    Sounds easy. I'm going to try it tonight.
     
  20. tcope

    Joined:
    Jan 29, 2015
    Messages:
    3,552
    Likes Received:
    1,396
    Location:
    Salt Lake City, UT
    Not saying calibrate in this position, just test level of the P3.
     
    dirkclod likes this.