It goes without saying that if you have to much vibrations, and at least when you can see the arms or other parts vibrating, you better get to the source of the problem first and fix it before adding dampers to the fc. Even if you manage to dampen the vibrations, they might lead to fatigue to electronics or other hardware at some later point.
I could not agree more. However in my case the frame is very solid and there is nothing visibly vibrating.
That said I could have motor caused vibration that while not visible is causing a problem on the machine. This I will check as soon as I can.
Check the play in the motor bells as well
Play in the motor bellsā¦yo mean like an up and down movement in the bellā¦ya thats on the list to check. But I ran each motor on the frame with out props and had no real vibration problem on a per motor basisā¦but I will dig into it further.
Thanks Andy.
I just saw Dr. Piperās post about increasing the ESC telem rate from 10hz to 100hz.
Hoooooooly crap!
Very noticeable difference in the sound of the quad now and it flies better than it ever has before. Incredible work! @andyp1per If you have any suggestions for improvement, Iām always happy to try.
One tip I gleaned from Leonard in another post - try increasing autotune aggressiveness to 2.0 after completing a tune at 1.0. Itās worked really well for me, but proceed at your own risk of course.
There are further improvements in 4.1 that will reduce the noise further, but setting the TRATE to 100Hz is a good start. I could not get it usefully above this - too many errors.
Beware, if your noise is low then 2.0 AGGR will overcook it - this happened to me and I started to get pitch oscillations on a 4" quad.
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Iām running the latest master, so I think Iām enjoying the 4.1 improvements?
When I did the 2.0 tune before going to 100hz and got a considerably better tune than on 1.0. To be clear this is a 3kg 13" prop quad.
Yes indeed
2.0 is fine if you are not getting oscillations - but you will only know if you push it hard. I was only seeing it on very sharp turns.
This is a very docile inspection aircraft that only flies in Loiter. My tuning goal is to achieve the best position hold performance possible.
Why would the copter sound quieter with the trate increased. Is this having an affect on the way the Notch filter works.
Also I assume this autotune aggression number is in the 4.1 version.
The autotune number works in any version AFAIK. Itāll say itās out of range, but it works fine.
Increased trate means that the filter is updating 10x faster than it was from my understanding.
@andyp1per I had a really strange thing happen today where all four motors cut, and the ESC stopped sending telem. I doubt its filter related, but Iāve never had anything like it happen before, and it was after increasing the trate. Hereās the post with more info.
@andyp1per Hi Andy,
I have a big copter(115cm frame, hobbwing x6 motor, 2388 props), tuning right now, So I check the FFT log and Itās noise freq is around 20hz, Is that normal? and the RATE, RCOU1-4, ATT, is full of noise.
You should probably do a bench test where you switch on BLH debug and see how many errors you get. I you are getting a lot then the TRATE is probably too high.
Not sure why the ESCs would cut out but we had DMA priority issues on the Kakute boards with Dshot. What board is this?
The peaks at 110Hz and 220Hz indicate that your first harmonic is different to 20Hz. More likely I would say 65Hz - in which case the 20Hz spike is weird - maybe just frame resonance.
Yes, I suspect that is a frame resonance too, I can see it when the copter hovering. Iāll try to find a way to get rid of it.
This is running an mRo control zero. Good idea on the debug.
Thanks for your response ā¦ still curious why the machine would be quieter.
At higher TRATE the notch will track the noise more accurately, with less noise you get less corrections for the noise and hence less motor fluctuations.
oooooooo me likey.
I assume then I can up it to 20hz then to 30ā¦I donāt need to go to 100 right away.
Yeah, but note, I am doing this on small high kv motors that will accept rapid changes of input quite readily. I worry than on larger, lower kv motors you may be stressing the motors or ESCās - @vosair I wonder whether this was behind your temperature issues. Might be worth dropping the TRATE to 50.
My guess is that setting the TRATE to the same as your INS_GYRO_FILTER value is probably a reasonable thing to do.
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