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Smoothing out tips

Posted by Nathaniel McMahon on January 31, 2018 at 9:47am

I've been flying with my alexmos Gimbal with a Sony A7r and occasionally get judders and shake in the footage. I tried yesterday without the in camera stabilization and it's a nightmare (hats off to the Sony). Here's a quick vid i've upped from today. 

https://youtu.be/BYW43pszDDI

It's a 910mm Octo running a Pixhawk 2.1, Copter autotuned. Gimbal Autotuned with extra refinement. I'm noticing very slight vibes watching the UAV in flight. Gimbal mounted on its very own dampning system by Hdair studio. I might cut up some earplugs and stuff the multiple standard little mounting rubber balls. I'm probably looking at a a manual tune of UAV PID's.

I'd just appreciate any tips if there's anything obvious or recognisable from the type of vibes I'm getting in the footage. I'm just a little shocked as my small quad with gopro never had such problems. 

Or if theres and obvious PID changes I should make from the autotune to smooth things out (decrease P perhaps).

Thanks 

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Tags: pid, gimbal
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Replies

  • Bob Smith July 25, 2018 at 9:32am

    I got out for a short test today.

    I switched the folding props which were certainly poorly balanced for balanced hard mounted CF. All 18"

    The video was just as bad, no different really (Although this is subjectinve).

    The VIBE numbers went from 

    VibeX max/mean 3/2

    VibeY max/mean 6/4

    VibeZ max/mean 10/6

    to 

    VibeX max/mean 3/1

    VibeY max/mean 3/2

    VibeZ max/mean 8/6

    I attached images of the VIBE log 07/11 id folding, 07/25 is fixed.

    I also disabled the gimbal altogether (disconnected power) and although it was uglier, the sideways vibration that is disturbing on the others is still there. 

    I am leaning towards to the 24 bushing anti-vibe plate as being a source of instability.

    Next test, replacing that with screws and seeing how no "damping" does.

    20180725_VIBE.jpg

    20180711_VIBE.jpg

    https://storage.ning.com/topology/rest/1.0/file/get/3702437680?profile=original
  • Nathaniel McMahon July 25, 2018 at 4:44am

    My props are also hard mounted. I'm thinking it's more to do with a balance between UAV PID responsiveness and the shock absorbers in the gimbal mount.

  • Bob Smith July 24, 2018 at 4:09pm

    I am using a home made gimbal based on RCtimer 5008 motors and Storn32. I have hard mounted the original balanced props on without quick release and will see if this helps. It's 107 here at the moment and I am happier inside working on theory. I hope to try it this week.

    Any suggestions of what experiemnts would also be helpful.

    Thanks

  • Nathaniel McMahon July 24, 2018 at 5:16am

    What gimbals are we using?

  • Ethan Scott July 24, 2018 at 2:18am

    I want to know too. Actually I am not sure how to make the stability of the video better, could someone help me out?

  • Bob Smith July 12, 2018 at 4:02pm

    Did you ever solve this problem? I just finished an X6 build and she flies great but my video with a Sony A7II is shaky. The vibe values in the logs look good. I was searching for ideas and found your "unanswered" question.

This reply was deleted.

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