Can soneone explain "gain" to me.

[jforkner]

I have a stock Naza F450 kit and I'm having trouble understanding the concept of what adjusting the gain in the Autopilot section of the Assistant software is really doing. I read that if it's too high, the craft will oscillate; and if too low, it's hard to control. While I get the oscillation part, I don't know what "hard to control" really means.

When I first setup my quad, I left the gains at the default settings, 100%. The quad seemed to fly fine; but then I'm new to quads, and had no point of reference. I noted in reading thru numerous posts on several forums that others were setting the gains in the 130-145% and higher range. So I bumped mine up to 135% across the board and the Attitude to 120%. Frankly I saw little or no difference when I flew with these settings. I suspect most of that is because I don't know what to expect from changing the settings; or, perhaps, I didn't make enough of a change.

I do notice that I can't seem to hold altitude for any length of time (say, more than a few seconds) without some throttle input. It seems to hold for a bit, then rises or falls until I give the throttle an adjustment. Maybe I'm expecting too much here, but I watch videos on the DJI site of guys pressing down or lifting up the quad in flight and it seems to return to the original altitude. Is that a gain adjustment I need to make?

Anyway, I thought if someone could give me a good explanation of what adjusting the gain really does, it may help me tune my machine.

Thanks for any insight you can offer me.


Jack

 

[Bowley]

Jack, The gain is basically the amount of controlling signal coming out of the FC.Too high causes overcorrection much like manual overcorrection an aircraft will oscillate about until you stop overcorrecting, so the craft will oscillate about the datum as you know, and likewise too low at it will take a long time to correct and may feel sloppy in the ATTI mode.
You may need to increase the vertical gain if your not maintaining altitude. Have you checked your Tx calibration to make sure 'centre stick' on the throttle actually is centre stick and you get full scale up down controls.
'Hard to control' in this sense means the self levelling ability of the craft is lower at lower gain so it becomes less stable.

Steve

 

[jforkner]

Thanks, Steve. I believe my Tx is calibrated properly. I think I'll try bumping up the vertical gain and see if that helps.

Jack

 

[jforkner]

Boy, did that help. I boosted all the gains up and it really settled things down. I took the vertical up from 135 to 150 and it holds altitude much better. Still have to touch the throttle once in a while, but not like before. Thanks for the guidance.


Jack