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Yesterday my Inspire started drifting

Discussion in 'Inspire 1 Discussion' started by bjornjd, May 24, 2015.

  1. bjornjd

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    Hi,

    Yesterday I did a couple of flights with my Inspire, testing it out a little bit. The first few flights went well, and the Inspire behaved as expected. I always calibrate the compass before every flight.

    But then on one flight, the Inspire started drifting north. I tried to get it back but I had to struggle with it a bit to get it home. Yeah you can see the result here:



    After I got it on the ground I checked the IMU, which all of a sudden needed calibration. I turned off the machine for 5 minutes, turned it on again, and then it said that the IMU did not need calibration. I calibrated it anyway of course. After the IMU calibration I calibrated my compass and took another test flight with the machine and it performed just as it should again.

    Scary!
     
  2. Eddie Haver

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    I'm not a pro yet by any means but from what I've read on here so far it sounds like you calibrated the IMU when it was not necessary. A lot of people have been having this issue because they calibrate before every single flight and end up having a big magnetic interference while they calibrate.... then it goes up in the air and is all thrown off. Basically if your numbers are good then don't calibrate it again. The old "if it ain't broke, don't fix it" phrase....
     
  3. bjornjd

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    Thank you for your answer Eddie, but I calibrated the IMU after it started drifting, not before. The compass however, was calibrated before takeoff
     
  4. Eddie Haver

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    Crazy, I would like to see some others get in on this hopefully. There have been a lot of helpful posts on this website. You could probably find an answer looking in other recent posts.
     
    bjornjd likes this.
  5. The Editor

    The Editor Moderator
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    The IMU can alter (slightly) with temperature so if it is on the threshold of needing calibration it could easily fall within spec again once cool.
    It is advisable to do an IMU calibration when the aircraft (and thus the IMU) are first switched on and not had an opportunity to warm up. Probably the converse to what you would think as logic would dictate you allow it to warm up and stabilise but there you go....what does logic have to do with it :)
    Don't forget that the IMU and the compass (magnetometer) are two distinct items within the Inspire.
    The IMU (Inertial Measurement Unit) is made up of a mems gyro unit and a 3 dimensional accelerometer sensor array.
    The compass is distinct and seperate from the IMU and is responsible for measuring the magnetic flux acting upon it for declination you are flying in.
     
    #5 The Editor, May 24, 2015
    Last edited: May 24, 2015
    lrwskyfilms and bjornjd like this.
  6. bjornjd

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    Thank you for your answer The Editor,
    Is there anything I can do to minimize the risk of this happening again?
     
  7. Mopar Bob

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    [QUOTE="
    The IMU (Internal Measurement Unit) is made up of a mems gyro unit and a 3 dimensional accelerometer sensor array.[/QUOTE]

    I know its a typo error, but just to be clear, the IMU is the Inertial Measurement Unit.
     
  8. lake_flyer

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    I know its a typo error, but just to be clear, the IMU is the Inertial Measurement Unit.[/QUOTE]
    you beat me with 36 minutes, good I checked before posting haha.
     
  9. The Editor

    The Editor Moderator
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    I know its a typo error, but just to be clear, the IMU is the Inertial Measurement Unit.[/QUOTE]
    Oppps.... Mi fongers sumtymes go kwiker than me brain duz :confused:...... Thanks
     
  10. Nick Galanti

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    I just joined the group here, thanks and learning a lot for sure.

    I just had a very similar issue come up where I put the bird in to have her started wandering to the right directly into a house managed to pull it left a little to avoid the house give it a little altitude to miss a tree and then tried to get it to land because it seem like the remote had zero control over the bird. It came down kinda hard on the camera but just scraped it up.

    I didn't have the multi flight enabled because honestly I just bought it 3 days ago and thought that meant something else.

    I hadn't had any other issues on other flights but I bought the bigger battery and upgraded the firmware on the battery and this was the first flight after that and things kind of went wonky. Any other issues I should be aware of?

    I took it out in a little higher wins in an open field and had zero issues after that.
     
  11. mandoplan

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    Hello everyone, first post here.

    Does anyone have any insight on the bolded part of Nicks post above? I'm having a similar issue. Getting drift horizontally and vertically after updating firmware on Batteries. More specifically I've noticed that my I1 doesn't "stop on a dime" like it used to and it seems far more susceptible to wind interference than it was before. I've calibrated IMU after the update but it hasn't fixed the issue. Any insight is greatly appreciated.
     
  12. Derfmen

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    Watching the video, I notice that the camera horizon looks off. It appears to be tilted slightly to the left. I have noticed in other posts about erratic flight control/behavior that in many cases the camera horizon is off by a few degree's during the incident and back to normal after re calibration, and the bird flew without further incident.
    Did you happen to notice if the horizon was level after you re calibrated?
     
  13. Shazbot4

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    what can happen is when your in a hover the GPS holds the aircraft pretty much in place. when you give it forward movement the wind can cause it to drift. the way to fix this is going into your settings and turning up the gps and altitude sensitivity settings. the cause of the drifting is because the gps and altitude sensitivity settings are to low for the conditions. some times people turn them way down so the flight is less jerky and allows more time before coming to a stop. if there is low or zero wind they can be turned way down and give a smoother shot. when these settings are turned up or maxed aircraft responds a lot faster but also makes movement less fluid and tries everything it can do to change directions start and stop as quickly as possible.

    the drifting is a side effect of the settings being to low.

    your welcome.
     
  14. pterrill

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    Shazbot4, Could you advise where in the menu you are finding sensitivity settings for GPS and Altitude. Are you talking about Gain & Expo Tuning?

    Thanks
     
  15. Shazbot4

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    im pretty sure it's in the gain and expo tuning menu. if you scroll down to the bottom past the throttle curves its below that I think.