Betaflight tuning

This has been bugging me for a few years now. How to tune your quad in Betaflight.
There’s all sorts of settings - P, I, D, d min. d max, i term relax, antigravity, feedforward etc

confused022

My 5" quad felt fine on 4s with flysky years ago. Then I upgraded to crossfire and suddenly the bounceback vanished (a wobble after a flip or roll).

Then I went to 6s. Major wobbles. So I tamed down the P and D terms and it was okish.

I now have a source 2 frame with titanium alloy arms and it just never feels right at 1/4 to full throttle. I’m guessing the arms are ringing like a tuning fork that needs filtering out. :man_shrugging:

Anyway, this thread is to show how I will try to tune my quad using the blackbox logs.

First off, I did a preliminary tuning flight tonight. And the stats are posted too.

I haven’t got a problem with the setpoint (no high frequency noise) so the rc link is sound. But I have harmonic problems at 150hz, 300hz and 450hz in the motors (they were hot on landing)

All help appreciated :+1:

It definitely isn’t motor related as they all have the same noise…

Although, saying my step response is fine… looks like there is a definite wobble. The motors were hot so the d term was working too hard, so I need to reduce the p/d term I think

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Will be watching this with interest, still dont have a clue about tuning with black box logs lol

Think you need a drone doctor.

Intrigued by this wizardry

Bear with me

Took her out this morning to try to tune.
I reduced the pd gains (master multiplier). It helped a ‘little’. But still massive vibrations.

I crashed (as usual) and put my dshot beeper on. I noticed the beeps where ringing.

I examined the blackbox and noticed noise at 160hz. So I put a gyro notch filter on at centre 160hz, down to 120 and up to 200.

Hey presto! Less noise. Easy peasy. I need another notch filter at around 100hz too I think. Here is the spectro of roll / pitch before and after.

Bottom line is, filter out the crap before trying to tune pids