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Aerial Videography and Photography Aerial Video/Photo from R/C Helicopters


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Old 01-06-2013, 06:51 PM   #1
streetpilot
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Join Date: Aug 2010
Location: Kelowna B.C.
Lightbulb PS1 W/Hoverfly gimbal Help

Okay so with everything on and running video looks pretty good and stable other than a quick pendulum effect every once in a while on the roll axis.... Today I tried turning off the gimbal stabilization and just flying the Heli with the camera recording and poof problem gone... So now I need to figure out what is causing this problem and how to fix it....

My setup is a Trex 700 stretched to 800, DFC head, edge 813's, kbdd extreme 112's, helicommand rigid, scorpion 4035 330kv, mod 1 straight main, kde adjustable motor mount, ps1 3x v2 gimbal, spectrum H6040's on gimbal. Heli is vibe free and flys perfect (hence good video with gimbal off) I'm using a 4 shock mount to the gimbal. 2 on an angle to the outside of the tubes and 2 vertical to the inside of the tubes (which greatly decreased the pendulum effect) and 100wt oil... And a hacked Panasonic GH2

So my thoughts as to what may be causing this are (in no order)

1. Shock oil weight and lord dampener stiffness (but video with gimbal off is good)
2. Hoverfly gimbal mounting location (currently mounted on camera tray but on the side)
3. Hoverfly gain settings ( I've spent a ton of time messing around with gains and have them set WAY lower than they came from factory)

So if anyone has any ideas it would be appeticated.... And if anyone else is using this same setup I'd be interested in comparing HFG gains and PID gains...
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Old 01-07-2013, 06:16 AM   #2
arrinick
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I have spent a long time trying to get the roll axis on my modified MKTR mount to be better than turned off. I can get the roll fine now (using piclok to stabilize), the settings are correct, servo is fast enough and smooth enough, I just run into mechanical issues - if the roll axis bearings are loose enough to roll smoothly, there is to much for and aft slop ;-)

I spent forever trying to figure it out. try lowering the sensitivity of the roll response. Smoother slower is better than jerky fast and oscilatey. I think a lot of those default settings are for go pros and the like, cameras with more mass need lower gain to get rid of the shakes.

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Old 01-07-2013, 12:12 PM   #3
streetpilot
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Location: Kelowna B.C.
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I'm using spektrum H6040's on all three axis,I've checked and double checked for slop and all is good... Last night I moved all 4 shocks to the outside of the tubes (mounted now in a V shape) and put 150wt oil in, so when I get home from work I'll give it another try... I think it's that between the play in the shocks and the roll servo moving all that mass just makes it oscillate? Idk we'll see what happens. I have my roll gain turned down from the factory 500 setting down to 85 and my PID gains are kP=55000 kI= 205000 kD=8000 and overall is 25.0
Probably completely different than the picloc gains work? The reason I think it has to do with the shocks is when the camera is facing either left or right there is no problem with the roll (cause its not rocking on the shocks)
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Old 01-07-2013, 07:09 PM   #4
pc3associate
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The GH2 is very light. In all honesty you might be going in the wrong direction. 4 shocks with 100-150wt oil seems too stiff. Once you finish testing the current setup try using 2 shocks with 60wt oil to see if you are heading in the right direction.
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Old 01-07-2013, 08:18 PM   #5
streetpilot
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Yes the GH2 is very light, but what I didn't mention is what I have on the tray, which is the camera, gimbal LiFe, Rx, hoverfly gimbal controller, 5.8Ghz Video Tx, and a digital to analog video converter. The video got 70% better by changing the shock orientation and oil weight... I'm thinking now i may just need to spend more time messing with gain settings or possibly the location of the hoverfly gimbal board... Thanks for your input!
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