Help configurint PID for the first time

[mateusviccari]

Hi people, im here because im losting hope to configure my quadcopter. Tried different settings but none went good.
First i tried to fly with the default settings, but the quad was wobbling a lot.
Then, i have read some tutorials and tried to set all the values on PID to 0 on ROLL and PITCH and increase the P until the quad wobbles.
But even with P = 0, it still wobbles!
Then, i increased P on ROLL and PITCH to 1.0, and saw no difference.
After this, i tried to mess with the I and D a little, until i set the I to 0.049 and D to 23. Doing this it flies much better, with a lot less wobbling, but still wobbles.
What im asking is, why changind the I and D made it fly better? what is the logic? What do i do now, to make it fly stable?

Some of you may say that this problem is the center of gravity, but i dont think so, because if i fly it in acro mode, it flies very stable, i can hover very easily.

[tovrin]

one of the greatest videos made for this very question, good luck!

[mateusviccari]

Yes this is the video i watched to learn to set up.
The video tells if there is wobbling in a high frequency, i should decrease P, but as i said, the wobbling stays even with P=0, and don't go out.
I think it may be related to the other sensors, like LEVEL, ALT, Pos...
But i couldn't find documentations about these...

[tovrin]

begins to sound like you have a vibration problem. use good paddingo n your FC, check for vibrations using the gui (in bluetooth if you can so you can watch vibrations while flying), you can also try using a LPF

[mateusviccari]

about this LPF...
This is not done in the multiwii GUI, it's done in the arduino code, right?
If i change the code, applying the Low Pass Filter, i need to set up the PID on the multiwii gui again after? Or, if doing changes on the gui, i'm gonna loose the LPF setted before through arduino?

[tovrin]

no, your pid info stays in eeprom, you will be ok changing lpf and nto affecting your pid settings

[Andy7]

one of the greatest videos made for this very question, good luck!

Good video. Though I think only good if you're flying in + configuration.
You'd need some kind of rig to do that if in X mode.

Tempted to build something becuse this is a great way to really study the behaviour and eleminate all the random environmental factors. I think I'd also be able to watch the vibrations too.

[tovrin]

as far as PID cause and affect the wobbles and flying characteristics should be much the same between + and X, right? Ive never flown a +

[Andy7]

as far as PID cause and affect the wobbles and flying characteristics should be much the same between + and X, right? Ive never flown a +

That's true, but he has the string tied to opposite arms and it's rotating about that axis. An X config quad would rotate about an axis 45' to that for pitch and roll.

[tovrin]

ahh, yes, i was mainly referring to the actual flying part in the beginning. i would love to have a nice string setup for a X, cant really be too hard to design...

[Andy7]

ahh, yes, i was mainly referring to the actual flying part in the beginning. i would love to have a nice string setup for a X, cant really be too hard to design...

It might work if you tie a piece to each pair of opposing arms. Gonna try some experiments when my busy life allows some play time. Will post pics.