How to enable harmonic notch filter in copter 4.03

i am not getting some parameters in full parameter list to test and enable the notch filter.

Make sure you enable it to see the other parameters

its showing a error missing para 1038 vs 1037

dose this value for LOG_BITMASK looks fine

Please explain exactly what you are doing and what you are expecting to see there is a detailed write-up in the wiki

i am building a custom hex copter i was having some vibration issue earlier so i have tried to reduce some it by adding some vibration dampening to flight controller(holybro mini pix) the vibration has reduced but later in some test flight i have noticed it sometime jumps on the z axis i have fine tuned some setting after reading Tuning Process Instructions
i was also thinking to enable the harmonic notch filter as someone recommend it. i got the error msg when i enabled it is that normal ?

last time when it got crashed the drone entered in vibration fail safe mode after i added some weight to it to test the stability.

about the LOG_BITMASK i was asking it says default value is fine the value (176126) its showing should i consider that the default value or the (830 Default) ?

Follow these instructions:

The error I think you can ignore. I think it might be a MP bug,

  • With the same log, open it in the regular way in mission planner and graph the throttle value. From this identify an average hover throttle value.

  • It’s also possible to use MOT_HOVER_LEARN = 2 in Copter and read off the value of MOT_THST_HOVER , or Q_M_HOVER_LEARN = 2 in QuadPlane and read off the value of Q_M_THST_HOVER

  • This gives you a hover motor frequency hover_freq and thrust value hover_thrust

pls explain these steps.

Throttle value is CTUN.ThO in your log
MOT_THST_HOVER is a parameter - look at its value after you have hovered for a while and landed
The hover frequency comes from the FFT you did earlier.

ok thanks sir, should perform auto tune before or after setting the harmonic notch filter.


More words needed

Hello, after checking recent logs i came up with these value

average hover throttle value - 0.20
MOT_THST_HOVER - 0.2850147

now is the hover motor frequency hover_freq = 0.2850147 and thrust value hover_thrust = 0.20


You should use 0.20 it doesn’t look like the learned value has converged properly and eyeballing the log is more accurate,

The frequency you get by doing an FFT on the log - details in the wiki.

which one i should consider?

FTT ACC = 105hz
FTT GYR = 103hz

103 hz …

I have done a test flight after setting up the notch filter.
there is a dip in FTT gyro but FTT acc still looks the same.

here are the logs

Hi, I wanted to know if you had solved with the setting of the notch filter … I was asking you this because I am also studying this part concerning the parameters to be used to best set the notch filter.
The wiki read and reread it but it is never an explanation like the one given by a person who used this function. In the wiki it is assumed that many things are known but for a beginner it is not so.

Hello since last month i dint got time for setting up the copter and it’s still not complete. i can suggest before setting up the notch filler it would better to first fine-tune the PID and try to reduce the vibrations physically as much as possible.

I would share the details as soon as i am done with it.

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hello, thank you for your quick reply … but reading the wiki it says that before fixing the pid with autotune … you reduce the vibrations mechanically … but then activate the notch filter and then do autotune …
Thank you again … and I continue to follow the various discussions about this topic on the forum.
Thanks again.