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Wind too much for gimbal? Anyone else have this problem?

Discussion in 'Phantom 2 Vision + Discussion' started by steele9999, Oct 20, 2014.

  1. steele9999

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    Tried to fly over a corn maze yesterday. I knew it was windy, but it didn't seem like any more than I flew in before (Phantom handled it well in the past) Before my flight I had checked a weather app which said the the wind was out of the NW @ 4 MPH with gusts of 17 MPH (no problem). As you can see in the video it didn't seem to bad when I took off. I ascended to about 120 feet and saw that I needed to be higher to see the entire field. When I started to rise the camera began to shake back & forth. The video signal on the app became scrambled. I thought the apps link was the problem until I saw the video when I got home. I also saw that the wind was stronger than I thought when I saw the wind-blown corn field below.

    Has anyone else had this problem? Is there any way to tighten the gimbal?

    http://youtu.be/LHrus2Yg1wU
     
  2. 480sparky

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    Re: Wind too much for gimbal? Anyone else have this problem

    The wind speed at ground level can be less (or more) than the wind speed even 100' up.
     
  3. Dirty Bird

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    Re: Wind too much for gimbal? Anyone else have this problem

    I've noticed moments when my gimbal is subject to a mild oscillation that it is unable to completely correct. ie, if I climb at full power on a windy day I will sometimes see very slight jello in the image. Reducing the climb rate eliminates the issue for me. Your gimbal problem, however, is much more pronounced than simple jello. In your video the gimbal appears to actually be malfunctioning. As you tilt the lens down it becomes worse, until the gimbal is just jumping back and forth on its yaw axis. It is actually bouncing back when it hits the limit of travel in right yaw. You may want to test this on the ground to observe exactly what she is doing? Perhaps a loose connector, damaged ribbon, or a faulty controller or motor?

    Watching your video again I am wondering if the problem was the wind was so strong that it caused your bird to compensate to the point where the gimbal when limp? Then when the angle was reduced it was kicking back in and repeating? I saw a lot of bank on the horizon and a lot of right landing gear which I don't normally see.
     
  4. Lefteris_gr

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    Re: Wind too much for gimbal? Anyone else have this problem

    I've got the same thing - a mild oscillation that shows up as jello. It appears more often when I climb at full power but it sometimes shows up even when hovering or cruising at a low speed with no winds. Its driving me nuts. I've tried several different sets of well balanced props and even replaced the motors with antigravity ones, hoping the vibration was caused by the bird rather than the gimbal. This has been going on since day one (i.e. approx. 70 flights ago). I really want to fix this, but am running out of ideas!
     
  5. steele9999

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    Re: Wind too much for gimbal? Anyone else have this problem

    I've seen from time to time slight vibrations in my videos, but this is like the camera just broke free and was being blown around.

    I shot this video at another location only 20 minutes prior to the corn maze video. I did not ascend to the same altitude but it was windy. I did notice some yaw movements (mostly edited out) in the mill video.
     
  6. Dirty Bird

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    Re: Wind too much for gimbal? Anyone else have this problem

    Assuming your dampers are good and the gimbal is floating freely, it might be the ribbon cables coming into the gimbal base transferring some vibrations from the aircraft. Check if the grey ribbons are taunt and give them a little slack if they are.
     
  7. Dirty Bird

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    Re: Wind too much for gimbal? Anyone else have this problem

    I agree it looks like it was going limp and blowing with the wind. Power her up on the ground and see how much range you are getting on all axes before it goes limp.
     
  8. DrJoe

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    Re: Wind too much for gimbal? Anyone else have this problem

    A while back I had a to replace my gimbal. I went for a few short test flights at low level, and all seemed fine. Then I went for my first long flight....

    My gimbal behaved exactly as yours did. It was as if the gimbal motors were sporadically losing power. I brought the bird back and checked it over. It appeared that one of the cables coming from the hull and into the gimbal was loose. I popped it up and replaced it firmly, and the problem has not returned at all.

    Perhaps you have shaken a cable loose, or started to. If you are looking at your gimbal from the front, you will see 3 cable ribbons going into the top. My problem cable was the one on the right. Gently pop it up, clean the contacts, and replace it tightly.

    Hope this helps.
     
  9. steele9999

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    Re: Wind too much for gimbal? Anyone else have this problem

    Thanks for your input. I'll check the cables when I get home tonight. I hope that's all it is.
     
  10. Lefteris_gr

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    Re: Wind too much for gimbal? Anyone else have this problem

    I've spent countless hours working on this and can't figure out how to fix it. The dampers are brand new, the grey ribbon cables have plenty of slack and I've replaced the anti drop pins with extremely thin fishing line. I've done the advanced IMU calibration, cleaned the gimbal's motors with an air can, checked the gimbal's potentiometer and done pretty much anything else that comes to mind. The bird flies great without any obvious abnormal vibrations. I'm assuming there's something wrong with the gimbal (possibly a motor having issues with some of the winding or an accelerometer being off) but can't figure out how to test those in a non destructive way. Keeps me busy and annoyed at the same time! Next step for me is to strap an iphone to the landing gear and run a vibration measuring app while flying. I will then cross-reference the data on the app with the jello on the video and that might help me identify if it's the bird or the gimbal causing the oscillations. Any other ideas are very welcome.
     
  11. 4wd

    4wd

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    Re: Wind too much for gimbal? Anyone else have this problem

    You can see from the way the corn is blowing it looks more like 15mph gusts - and could easily be twice that higher up.
     
  12. badbrad97

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    Re: Wind too much for gimbal? Anyone else have this problem

    That is what it was. The wind was so strong up that high that the gimbal was trying to do a re-calibration. Some gimbals are more sensitive than others to weight, balance and other factors.
     
  13. steele9999

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    Re: Wind too much for gimbal? Anyone else have this problem

    I checked all the gimbal cables when I got home and nothing seemed to have loosened. I reseated them to make sure. I powered up and discovered that I now have the dreaded "gimbal dance"

    http://youtu.be/nZE9fQKg4eY

    I guess I have to start looking for those threads now. it's hard to believe that the wind could cause this.
     
  14. flyNfrank

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    Re: Wind too much for gimbal? Anyone else have this problem

    That looks pretty violent just to be the wind only. I have flown in wind much worse and my video is solid. My P2V would have such stuff going on, but not my vPlus.
     
  15. Dirty Bird

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    Re: Wind too much for gimbal? Anyone else have this problem

    I'm leaning to believing the gimbal was malfunctioning during the flights. I've flown in some pretty serious winds and never had my gimbal behave like your's was in flight.