Need some help with Harmonic Notch Tuning

[k08056787 (Kevin)]

I got a quad fly well with Pixhawk4 Flight controller, but for some reason I need to change the FC to Cube Orange. Since then, the vibration went too wild and unstable, so I started the Harmonic Notch Tuning with the guide from Docs.

The quad did much better after some tuning, but there is still some unstable up and down movement once a while. And I don’t know what parameters to adjust now.

Quad Setup below
FC : Cube Orange
GPS : Here 3
Motor : MAD 5008 KV340
Props : 1760 Composite Fold
Weight : 4 kg

Pre-filter
FFT

BIN
https://drive.google.com/file/d/1iybI7XgZVYqayEVn8859P5m8I0KuI1YZ/view?usp=sharing

After some tuning
the params are

|INS_HNTCH_ATT 100|
|INS_HNTCH_BW 35|
|INS_HNTCH_ENABLE 1|
|INS_HNTCH_FREQ 48|
|INS_HNTCH_HMNCS 3|
|INS_HNTCH_MODE 1|
|INS_HNTCH_REF 0.2|

Post-filtered
FFT

BIN
https://drive.google.com/file/d/12xAWoygUXK3fNXEcuRMCwUbbyVHntS0w/view?usp=sharing

Thanks for the help!!

[Luciano_Andreani]

Hi, what program do you use to get those graphics.
Thank you

[amilcarlucas]

@k08056787 NS_HNTCH_REF 0.2 <- looks like you did not change the default?

@Luciano_Andreani That is Mission Planner (as always, use the beta version)

[k08056787 (Kevin)]

After hover learning, my MOT_THST_HOVER is 0.2, I tried to multiply the square root of (min_freq/hover_freq) like the guide says and turned INS_HNTCH_REF to 0.07. But the situation got a lot worse, so i changed it back.
Thanks for the reply!! Is there any else that I can try? Or just keep tuning up the INS_HNTCH_ATT?

[amilcarlucas]

Did you learn hover in stabalize or acro mode? It won’t learn in those modes.

[k08056787 (Kevin)]

In AltHold Mode. I’ll learn it again tommorrow

[amilcarlucas]

Altmode works fine, no need to repeat it

[amilcarlucas]

@k08056787

INS_HNTCH_ATT

That one is perhaps too high

[k08056787 (Kevin)]

Yeah the default was 40 if I remember. The quad got better as i tune it higher.

[dkemxr (Dave)]

I think it’s inadvisable to set an attenuation so high. I would set it back to standard values.
INS_HNTCH_ATT,40
INS_HNTCH_BW,24
INS_HNTCH_ENABLE,1
INS_HNTCH_FREQ,48
INS_HNTCH_HMNCS,3
INS_HNTCH_MODE,1
INS_HNTCH_REF,0.2

[k08056787 (Kevin)]

Thanks for the reply.
Sorry that I didn’t show all the information up here.
So the picture below is what I tuned and how the FFT showed up.

0. Pre-filter FFT
   

   

1. tuning from default
   INS_HNTCH_ATT,40
   INS_HNTCH_BW,24
   INS_HNTCH_ENABLE,1
   INS_HNTCH_FREQ,48
   INS_HNTCH_HMNCS,3
   INS_HNTCH_MODE,1
   INS_HNTCH_REF,0.2
   

   

INS_HNTCH_ATT,50
INS_HNTCH_BW,24

INS_HNTCH_ATT,60
INS_HNTCH_BW,30

INS_HNTCH_ATT,80
INS_HNTCH_BW,30

INS_HNTCH_ATT,100
INS_HNTCH_BW,35

INS_HNTCH_ATT,110
INS_HNTCH_BW,42

Hope that this is better to know the problem!