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Oscillation after CFIT

Discussion in 'Inspire 1 Discussion' started by Gigantor2104, Sep 14, 2015.

  1. Gigantor2104

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    Hi everyone,

    First of all, hello and thank you to everyone who's made this community such a helpful resource! I've technically had my Inspire 1 for a few months, but a big portion of those were flightless due to a bum USB port on the controller that never allowed me to perform the initial setup... but that's another story.

    I've been piloting nano quads for a few months, mostly terrorizing my dog all around the house ;) but the Inspire is my first experience flying a platform of this complexity.

    First flights went really well... and on the weekend, feeling pretty good about myself, I miscalculated the distance to a tree and got a lot closer than anticipated. Luckily, the Inspire got entangled with a small, flexible branch, but the gimbal and gimbal mounting plate got torn off.

    I eventually retrieved the Inspire (stuck on a fairly high branch), and reassembled everything. The tally was pretty light, all things considered: damage to all four props, a cracked lens filter on the gimbal, and not much else.

    After reassembly (including four fresh props, of course), I was able to successfully take off and fly around. A few minutes in, I got a 'Gimbal Overload' error on the status bar, so I landed. Powered down, powered back up, and tried again. I flew a few more minutes without the warning, then reached a low batt state and came in for final landing.

    I watched the footage, and found that while the camera was steady throughout the first flight, there was a rhythmic oscillation on the second and third flights. I must have either mounted the gimbal vibration dampener incorrectly, or not noticed other damage that occurred during the collision. Any thoughts/suggestions on what to look for? I'm happy to process/post the before/after footage later this evening, if it helps.

    Thanks! Really looking forward to getting the bird back in the air (and keeping it away from trees!!!)
    Cheers!
     
  2. Scotflieger

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    @Gigantor2104 Welcome to the forum and sorry to hear about your mishap. As you found it is very easy to become a little overconfident in the abilities of this superb aircraft. The propellor marks on my shed door still bear witness of an early strike.

    If as you say the gimbal and anti-vib plate came off, I would suggest you check the interconnecting cables and connectors for any damage. If these are still serviceable, then it looks likes you have some internal gimbal damage. The damage looks like it is placing additional loads on the gimbal which is being detect after several minutes of flight. I would connect DJI as the aircraft and gimbal are likely to need to go back for repair.
     
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  3. Mossie

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    This may or may not help. I had a crash 6 months back , breaking my gimbal mounting plate and a couple of the supply leads. After I repaired it the gave all sorts of warning messages and would tip to one side if I banked the a/c.
    I did a gimbal auto calibration and since then it has worked perfectly. Hope it helps !
     
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  4. jon b

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    Hi there and welcome. I think you got a few good tips to try and see if you can sort out the gimbal issue without sending it in. Good luck there.

    Being new to this bird, it's easy to get carried away, go too fast, too close etc. In my years of flying it became clear that less aggressive flight gives the best shots... Be careful not to fly over your head and behind you cause it's amazing what awaits your bird out of your line of sight. Also, be careful about using partially depleted batteries. This forum has many stories about rapid depletion of cels that were partially run down.

    The forum here has a wealth of great knowledge from first hand experience. It's worth a lost afternoon or two to become familiar and the resource tab is also worth checking out

    Have fun and safe flying
     
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  5. Gigantor2104

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    Thanks for the suggestions! I'll try auto-calibrating the gimbal to see if that does it.

    I hadn't considered the possibility of internal gimbal damage, but I shouldn't rule it out. My first thought was that it might be due to an aircraft vibration/oscillation, but maybe it's the gimbal.

    The cable (the narrower one of the two) pulled out of the connector, but with some careful fiddling I was able to reinsert the leads fully and reconnect the cable; after my first (failed) attempt I got an 'aircraft upgrade failed' error message, but on my second try everything seemed to check out fine. Will definitely order a replacement cable, but the field repair held up to my two post-crash test flights just fine.

    Here's my plan (comments welcome!):

    1) Auto-calibrate gimbal
    2) Check for image oscillation while unpowered on ground
    3) Check for image oscillation while while unpowered and handheld (banking in different directions to test correct functioning of gimbal)
    4) Check for image oscillation while while powered up but on ground
    5) Check for aircraft vibration while powered up but on ground
    6) Check for image oscillation while hovering
    7) Check for aircraft vibration while hovering
    8) Check for image oscillation while in motion (vibration will be tougher to diagnose!)

    This should hopefully help to narrow it down! I'll post an update once I give it a try.

    Cheers, and thanks for the help!

    Edit to add: the Resources tab was really helpful! And I agree - it's such a great flying platform that confidence can very quickly exceed skill! Any suggestions on where to find drills/exercises to build flight skills? Or is it just practice, practice, practice?
     
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  6. jon b

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    quick question... If you remove the camera and manually swivel each motor through it's range of motion, does anything bind or grind at all? Doesn't take much to overload the gimbal and it's amazing how delicate the device is/how easy it is to bend something.
     
  7. Gigantor2104

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    Interesting thought - I didn't notice anything unusual while handling it, and in the startup sequence it went through its usual motions without anything looking off - but it's definitely worth looking at. Stay tuned!
     
  8. jon b

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    Just mentioned as I once received a new Inspire with a little grinding noticeable when I manually manipulated it. The camera eventually overheated when used. Got a replacement from B&H no questions asked
     
  9. Gigantor2104

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    OK - no flights this evening, as the weather doesn't allow. Here are my test results:

    0) Check gimbal for smoothness throughout range of motion
    Result: OK

    1) Auto-calibrate gimbal
    Result: OK

    2) Check for image oscillation while unpowered on ground
    Result: OK

    3) Check for image oscillation while while unpowered and handheld (banking in different directions to test correct functioning of gimbal)
    Result: OK

    4) Check for image oscillation while while powered up but on ground
    Result: OK

    5) Check for aircraft vibration while powered up but on ground
    Result: OK (spun up full throttle with propellers detached)

    ... But wait, what's that?

    The good news is that I figured out what's wrong. The bad news... well, see for yourselves.
    o_O:(:mad:

    IMG_1161.JPG
    IMG_1162.JPG

    How bad is it? Looks like a relatively straight-forward repair to a skilled tech with the replacement part... but maybe not. Thoughts?

    Thanks!
     
  10. Transpire

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    Found this online. This is what is in store for you...

    [​IMG]
     
  11. Scotflieger

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    It's back to DJI for repair as this level of repair can only be done in-house. This is because of the level of jig work and set up for the rotating gear members.
     
  12. Mohan

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    Has the arm moved backwards or bent? Looking at the warranty sticker it doesn't appear to have rotated?

     
  13. Gigantor2104

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    Neither - it snapped, but not all the way through. The boom bends slightly at the break (which I'm sure is the cause of the oscillation I found in the video), but otherwise appears to be straight and level when unstressed.
     
  14. Gigantor2104

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    That's what I feared... I'll call the DJI dealer to see if they can order the part and do it here, to avoid shipping the whole thing back and forth (which might be as expensive as the repair itself)...
     
  15. jon b

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    Yep, that'll do it. I'd send it to DJI. There's a post about a guy who repairs the carbon and might save a few bucks but...

    Sorry for you mate
     
  16. Gigantor2104

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    OK, took it to the dealer today. As luck would have it, they had spare parts on order, and the replacement boom should be arriving at some point next week. Hopefully means I'll be airborne by next weekend. Having fun with my micro quad in the meantime :D