You need to look for repeating peaks at multiples of a frequency, Although the biggest peak is at 140, you have another at 70 and a very small one at 210. Thus your fundamental frequency is 70.
You should set:
INS_HNTCH_FREQ = 70
INS_HNTCH_BW = 35 (half of fundamental)
because you have INS_HNTCH_HMNCS set to 3 that will create a notch on the fundamental (70) and the second harmonic (140). If you set it to 7 (so 111 binary) then it will cover the third harmonic at 210 as well, but its probably not necessary.
FREQ and BW determine the shape of the notch. This shape will be kept constant for all the harmonics, so at 140 the system will make the bandwidth 70 etc
Man I am glad yo know what your talking about cause most of that went over my head.
So I think your telling me that I have three bumps in frequency. per the graph I attached.
Your saying to set the Frequency to 70 which is the first peak with a bandwidth of 35…the axe wedge as you told me. The fundamental I think is the 70hz…or first peak. So half is 35.
I didn’t realize unit you pointed it out that these are harmonics. 70 140 210…interesting.
What I don’t understand is if I have the harmonics are to 3…cause I am brilliant…um no I have no idea how that came about…Anyway…if its set to 3…it hits 70 and 140 hz…isn’t it 3 harmonics…why does it only touch two 70 and 140 and not 210 which would be 70 hz out from 140. Just curious.
Other then that one question I will give it a whirl…thanks guys. As always I really appreciate your help.
I assume I have to set the logging differently to capture the post filter noise. INS_LOG_BAT_OPT,2
Imagine that each unit in binary represents each harmonic, if you were to put 5 in it would hit 70 and 210 but not 140.
At least this is how I interpret it.
Ok wait…now thats confusing. @SimonOakes if you put 5 for the harmonics…why does it do 70 and 210 but not 140.
I think my assumption is in correct. I am thinking that if 70 is the fundamental frequency, and the harmonic is set to 3 it would hit 70 140 and 210.
70 the first harmonic
140 the second
210 the third…
But your suggesting something odd. Setting to 5 would miss 140…why. @andyp1per
In binary
1 = 0001 - first harmonic
2 = 0010 - second harmonic
3 = 0011 - first and second harmonics
4 = 0100 - third harmonic
5 = 0101 - first and third harmonics
6 = 0110 - second and third harmonics
7 = 0111 - first second and third harmonics
hahah thanks for that Dave.
The dummies doc is for me, so I stop bothering you and @andyp1per
good thing is I think I am starting to get it…takes a bit. Fly day tomorrow…shall see how the filters work out.
Tarot 15 iinch.
I checked them all this morning to see if the blades weight is off in each pair. But apart from one prop. Each blade weighed in at the same…basically they are a matched blade for each prop. So the only other item I can think of is the hub and I checked each hub for balance and they are spot on…So I am truly puzzled.
I experienced vibration at certain point across the throttle in some folding props. Usually at 60 to 70 percent. Is it similar or is it all over the throttle band?
#https://photos.app.goo.gl/gYh1htYjddxs8uRe7
Hello guys!
I have difficulties to tuning the harmonic notch, I have tried different frequencies and and their corresponding bandwidths but I always have high peaks. These pictures show it:
You’ve done the right things. According to the log your hover thrust is more like 0.35 so you should set your REF value to that.
Also this is a cube black with 3 IMUs and you are asking for 3 harmonics. Try turning off the second and third IMUs just to see if its CPU related.
