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Pumpkin drop event

Weird Quad Oscillation

#1
Hello everyone on the FT forum!

As I am new to building quad copters and this forum please excuse my lack of knowledge on the subject. I am, however, somewhat experienced with RTF multi rotors and flying in the different modes.

Now let's get down to business....

quad - Copy.jpg
Quad Rear-.jpg

I recently purchased my first set of parts for building a quad copter, including a CC3D board. After my initial set up and several hours of internet browsing for tuning and programming info I was able to get my first flight without incident. But after a few attempts at changing the P values for the attitude mode I noticed that there was a constant oscillation issue (or what seemed like more of a twitching) no matter what settings I would use, even in rate mode! So after a few more days of no success I now come to the experts here for help.

Here is my setup:

Frame; Quanum Neon 250
ESC; Favourite Sky 3 Quattro 12a x 4 (4 ESC's in one)
Motors; EMAX MT2206 1900 KV
Flight Controller; CC3D
Reciever; 4ch Spektrum (Can upgrade to 6ch if necessary)
Transmitter; Spektrum DX6

Included are 2 pictures and a video of different p values I will use as an example of the persisting oscillations I keep having despite wildly different PID values.
I have tried a .5 all the way up to a 6 P value until the quad almost flips from over correction, and have only dabbled a small bit into the Integral values while in rate mode but the same type of oscillation is always there.

P10.png
P25.png

And a YouTube video that shows you the problem I have while flying during the 2 different tunes. I only use a 10 and a 25 Proportional value so I can keep the quad in the frame and/or not flip over, but I have tried extremely low values and extremely high values to no avail. (I have also tried to switch the type of ESC from fast to standard in the vehicle setup wizard but I see no difference in performance or stability between the 2 settings)

https://www.youtube.com/watch?v=Xp_nrg981ro
 
Last edited:

CrashRecovery

I'm a care bear...Really?
Mentor
#3
check your props. I know they are small but a vibration will cause the board to make the quad to shake. Something could be out of balance.
 

Snarls

Gravity Tester
Mentor
#4
Interesting. I think your problem probably resides in some other setting besides P. First I would tune in acro mode (rate mode?) instead of auto-level. Then I would go into the advanced or expert tab and find the place to adjust I and D gain values (I am assuming that in there). It's possible one of those values is off, like I being too high.
 

cranialrectosis

Faster than a speeding faceplant!
Mentor
#5
Snarls is right. Always only tune in rate mode. Any auto leveling ruins the tune.

The second thing I will suggest is put the copter on a dinner plate in the grass and hover over the lawn, not the concrete driveway, and POP your copter up at least 1 meter above the grass to get out of your own wash.

Your own wash (particularly above the concrete) will add to any wobble and make things MUCH harder to tune.

A too high P gain wobble is usually pretty fast and is often accompanied by a tendency to rise without throttle or to bounce back up on landing. A too high I gain wobble tends to be slower and gets worse over time particularly when you fly in your own prop wash.

If I were you, I would cut that I gain in half, fly over the grass no lower than 1 meter up in rate mode and see what happens.
 
#6
Thanks for all the replies! Turns out the open pilot software had defaulted to 50hz motor output rate. After changing it to 490hz it doesn't wobble and twitch anymore. Flies great!

I'll upload some videos later