D value in PIDs tuning when it’s too high?

Hi all,

I am tuning a quadcopter for a while but couldn’t get rid of a Vibration in the 50Hz area. The airframe default PIDs values are as follows:

ROLLRATE P: 0.08

ROLLRATE I: 0.02

ROLLRATE D: 0.003

PITCHRATE P: 0.13

PITCHRATE I: 0.02

PITCHRATE D: 0.005

My question:

I found the best log file with lowest vibration values achieved when increasing ROLLRATE P to 0.085 & increasing ROLLRATE D to 0.005 is that bad to raise the D value from 0.003 to 0.005?

Note: the quadcopter airframe is not symmetrical.

Thanks

It depends if it is needed. Increasing D will amplify the noise, but will also reduce the overshoot. You can follow this guide for tuning your drone.
Also, a vibration around 50Hz you can’t get rid of might just be the propellers themselves that produce the vibration.

@Mr_Madsen how to know if the D term increase creates noise which chart that shows inefficient performance in log analysis so I can evaluate the situation please.

Not sure what the best way to see this is. But the two options I can think of are: simply checking if the motors get hotter than usual during flight since this happens when there is too much noise. Or the second option would be to look at the actuator outputs and see if they jump a lot, but this option is a bit tricky, since a lot of other things can cause the actuator outputs to jump, and it is rarely the D term.
But since you are only raising it from 0.003 to 0.005, where 0.003 is the default for the frame, I don’t think you will see any significant problems with noise amplification.

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@Mr_Madsen thank you for your support madsen. I’ll keep monitoring the motors and performance and see how it goes.

FMI, did you try an autotune?