Good day! Last video we set up Betaflight RPM filters for both vBLHeli_32
ESCs on our Rattler build and also BLHeli_S ESCs on our FlexRC Colugo biuild.
The Betaflight RPM filters were really easy to set up with 3 main steps and the
detailed step-by-step checklist made available through the link in that
video's description. I'll put a link down below in this video's description as
well. We ended that video with the completed setup but we didn't get the
chance to actually SEE how the RPM filters work. So today we're gonna do
just that. Although I've flown both quads with the
RPM filters engaged and they FEEL as though they fly amazingly, today we're
gonna take an objective look at the results of RPM filtering through our
Blackbox Explorer. This will not be a highly detailed, in-depth Blackbox
analysis. Instead I'm just going to take a quick look at the gyro traces and
spectrograms of flights both with rpm filters engaged and without RPM filters
engaged using our Rattler build with BLHeli_32 ESCs. If you'd like to see a similar
video with the results of RPM filtering using JESC or JazzMaverick on our FlexRC
Colugo with BLHeli_S ESCs, just let me know in the comment section below. If
you're ready to actually see graphically if RPM filters will work for you, then
give this video a "thumbs up" below, share it with your friends, and subscribe your
TMac FPV channel - your home for your "Journey to Better" fFPV fun, flights and
racing stuff! For our flight without the RPM filters engaged, this is our
configuration in the configuration tab. We're running DShot 600, 8k 8k,
the bi-directional DShot is toggled off and we've got the dynamic filter toggled
on. Our filters setup for our first flight without the rpm filters engaged
is as depicted here. For our flight with the RPM filters engaged, this is our
configuration setup: DShot300, 4k 4k, bi-directional DShot toggled on,
dynamic filter toggled on. The filter setup is as depicted here based on
inputs from the Betaflight 4.1 tuning notes. All right, now that you've seen
both the configuration and the filters setup for without rRPM filters and with
RPM filters, before we get started I want to explain a little bit of what you're
about to see. We've got all three axes on this display - roll, pitch, and yaw. This
reddish color is the unfiltered gyro for each axis. So this (what I'm highlighting
here) is the unfiltered gyro trace for roll, unfiltered gyro trace for pitch, and
unfiltered gyro trace for yaw. The other color is the gyro trace after filtering
for roll, pitch, and yaw. Down here we have each of the motor traces - one, two,
three, and four. Here you have your stick displays - throttle and yaw on left, pitch
and roll on the right. Here you have your craft display. I've accomplished two
flights. The first flight is without RPM filters engaged and the second flight is
with RPM filters engaged. I'll go ahead and run through the first flight at full
speed up until the end of our second maneuver. For each flight both without
and with rRPM filters engaged, I've conducted two maneuvers. The first
maneuver is a flip over the roof of my house and the second maneuver is a roll
over the roof of my house. So first I'll run this first flight without RPM
filters at full speed just to show you what the flights look like then,
following that, I will show you a side-by-side comparison of both the flip
maneuver and the roll maneuver for without RPM filters engaged and with RPM
filters engaged so you get an idea of how the traces look for each side by
side. Now what we're looking for here is the thickness of these lines. The thicker
the lines basically, the more noise. So we want as thin of
lines as possible. Now having said that, I've made these look as bad as possible
by turning on Expo. If I turn that off they obviously look better. Turn it on, it
looks worse. I've also turned off smoothing. If I turn on smoothing, these
lines get really skinny. If I turn it off, they get more fuzzy. So I've made it look
as bad as possible. I've also zoomed all the way out. Where that looks nice, that
doesn't look so nice. So I've made it look as bad as possible just to
highlight the differences. So let's go ahead and run this first at full speed
and then we'll take a look at the side-by-side comparisons for without RPM
filters and with RPM filters for both the flip and the roll maneuver and then
after that we'll take a look at the side-by-side spectrograms
for all four motors without RPM filtering engaged and with RPM filtering
engaged. In the front, I'm going to go around my front tree here and then I'm
going to flip over the house.
Then I'm gonna go back to the front of the house,
go around the tree again, and then do the roll over the house.
So that's what you're gonna see side-by-side - the flip and the roll for both
without RPM filtering and with RPM filtering, except I'm gonna do it at 50%
speed.
Alright here we have the side-by-side comparison of the flip maneuver both
without RPM filters and with RPM filters. This top row is without RPM filters, the
bottom row is with RPM filters. We can compare the gyro on the roll, pitch, and
yaw, as well as all four motors for each when entering the flip in this column,
mid flip (in the middle column) and exiting the flip (in the last column). Keep
in mind we're looking for thinner lines. So having said that, which of these lines
look like they're thinner or cleaner to you? Let's take a look at the roll. Here
we have the same setup for the role without RPM filters up top and with RPM
filters at the bottom - entering the roll, mid roll, and exiting the roll. Once again,
which of these lines look thinner and cleaner to you? Next we'll look at a
side-by-side comparison of motor noise for both without RPM filters and with
RPM filters by taking a look at their spectrograms. All right, here we're gonna
start taking a look at the spectrograms for each of the four motors motors
1, 2, 3, & 4. These charts show you the amplitude of the signal and noise for
each of the motors. This top row is each of the motors without RPM filters
engaged, whereas this bottom row is with RPM
filters engaged. i've chosen to look at all four motors as i'm entering each of
the maneuvers - the flip, and also next we'll take a look at the roll. The reason
I chose to look at the entering point of each of the maneuvers is that's when I'm
increasing the throttle to accelerate over the roof of the house entering the
maneuver. So if you compare this top row for each of the motors without RPM
filters engaged to this bottom row with RPM filters engaged which row from your
perspective has less of this green stuff in it? This green stuff being the signal
and noise on each of the motors. Alright let's go ahead and take a look at the
same thing for entering the roll maneuver. Here we're entering the roll
maneuver, increasing throttle to accelerate over the roof of the house to
enter the roll. The top row is without RPM filters, bottom row is with rpm filters.
From your perspective, which of these rows has less green stuff in it? So now
we've all actually seen through Blackbox Explorer that Betaflight RPM filters
actually do work! Let me know in the comments below what you now think of
Betaflight RPM filtering and whether or not you'll implement it on your quads.
For more free resources, make sure to check out my site at TMacFPV.com.
Thanks for your time. I'll see you next video. Clear skies friend!