I have tried quick tune script on my 3,5 inch cinewhoop on arducopter 4.6-beta5.
The problem is that after tuning, I experience huge oscillations, especially those visible in the second log file. After tuning PIT_P param, it starts vibrating and proceeds to YAW param.
As a result, I have got much worse tuning than it was before. I set all default parameters for the script.
As a result I have got more noisy drone (can hear it) with kind of propwash on throttle and rolls.
Maybe standart quick tune parameters are not ok for whoop 3,5inch, but I can’t guess how to update them.
What is the criteria? if less than -50db, we don’t care about any other harmonics peaks? or anything else?
And BIG question about INS_HNTCH_FREQ. It shoult be equal to 1st peak frequency or a half of it as you set? Usually in the documentation/wiki/youtube it set equal.
I did estimated postfilter with your parameters and I still can see noize peak from 2nd, and 3rd harmonics:
With the original settings in place, the noise is filtered (earlier it looked to me like filtering was ineffective - not sure why that was) and the notch filters are right across a whole lot of the spectrum.
You can see the post-filter lines are still right across the bottom of the graph, and noise from the 2nd and 3rd harmonics and everything else is not getting through.
It’s not necessary to get every tiny bump of noise knocked down to absolute zero.
Key is that the standard Gyro filter is low pass, so eventually everything above 100Hz (in your case) gets attenuated at least some amount. The notch filters are there just to target whatever peaks get through the Gyro filter. In most cases it’s not necessary to target every peak and bit of noise you see, just the 1st harmonic, sometimes the 2nd.
In this graph the green line is the combined effect of the Gyro low pass filter plus the notch filter
The ESC-based filter will not go lower than INS_HNTCH_FREQ and scales up with RPM. Bandwidth is scaled up with RPM too.
So if you set the frequency too high it will never reach lower frequencies and RPM. You have to set something realistic, where motor RPM might still be valid.
If using just one notch then bandwidth is typically half of the frequency, and if using per-motor notches (Multi-Source) then we use about a quarter of the frequency, as a rule of thumb.
Of course the bandwidth value can be fine tuned, just use the minimum value that does the job.
