Gimbal pitch shaking, ideas needed.

[dockman]

Been trying to get rid of this shake for weeks now, I have been able to reduce it some but can never get rid of it completely.  It is kinda ok when hovering but as soon as you start to move in any direction it all goes to crap.  Different power sources tried, all sorts of settings, rc input removed, balanced many times with various cable routing tried.  2 axis gimbal with alexmos board running 2.40b7.  Input appreciated.

https://www.youtube.com/watch?v=I26fE5aRuBk&feature=youtu.be

Feel I should mention that when tuning the gimbal on the ground it works great, it is when it is in the air the issues start.

[Oakie]

couple of things i can think of trying.

resonance banding, get some water pipe insulation. cut a random 1 to 2 inch bit and apply to all arms and start removing 1 at a time. or add one and keep adding to each arm. your hoping for a change or cure to the problem. sounds odd but it may be a resonance extenal to the alexmoss from one of the motors.

Try testing on a min yaw to max yaw of gimble. adding 5 deg or so each test.

looking at the video and at worst when moving

So i do not know the alex moss board so can not offer any assistance re that. i would say that it is not chatter as such. the moss is trying to remove somit it is senssing so i think its vibration orientated from the fram....


Hope it helps.....

[flybywire]

Odd.  Only thing I can think of is the motor power setting.  Is it getting enough juice?  ARe you powering it off a balance plug?

Edit: looking at the footage again, it does look like vibes to me.  If you say it';s 100% fine on the ground, with no juddering, it must be either vibes, or a power issue maybe? (lack of).

[richardg6paj]

I have no solution, but it';s interesting that the movement is on the pitch axis and not at all on the roll.
Could it be a motor problem. Swap them over to eliminate. Has the sensor cable plenty of room to move. Is the sensor cable being affected by downdraught. Other than that, maybe a board problem or settings.

Richard

[n506]

Reminds me of an attempt I made to put a gimbal forward on the frame of an F450 style Chinese frame (in a semi TBS Pro style position). The gimbal was a little heavy on the single part of the frame that comes forward and I was actually getting flex in this part of the frame, which would get itself into a resonance issue pretty quickly. The problem also was it was shaking up and down which a pitch controlling motor has no real ability to deal with and it creates merry havoc. My solution was a change of frame which had two parts extending from the frame at the top and bottom so that there was no ability for the gimbal mount to flex up and down. Seemed to cure the problem nicely, and is more like the style of the TBS Pro in the way it is now held.

Only mentioning this because it may be something you';ve tried rather than the more classic underslung method.

[Oakie]

also maybe check the legs, when on the ground they compressed,no vibration. when flying it hangs loose as it has no weight compressing it.

no ideas......

[dockman]

The issue has been solved!

Camera needed a more secure mount so the guys over at Quaternium made this for me.

[flybywire]

That';s a beautiful rig you have there dockman, a work of art.

[Cloudbuster]

I have exactly the same problem with a quanum gimbal with a nex 5 fitted. Any chance of the details where i can obtain the extra bracket .... Nice quad by the way dockman ...

Regards rob

[dockman]

The bracket was made for me by the guys at Quaternium who are the ones that make my frame.  It is designed to work with the gimbal that comes with the frame but you could always contact them and ask about it.