Managing Gyro Noise with the Static Notch and Dynamic Harmonic Notch Filters

I’m getting ready to dig into some more detailed tuning of my Hexsoon EDU-450. I started with the parameter file for this copter available on Mission Planner - and have since done an Auto Tune and calibrated my compasses using the MavExplorer Magfit.

Reading the doc on Managing Gyro Noise… I found that the documentation doesn’t quite match what happens in the current version of Mission Planner. Doing the “Cntl-F” followed by selecting the FFT button, I get the screen with six graphs - but the options across the bottom are different than what’s in the ArduCopter docs.

Is there updated documentation available? Many Thanks!

You only need one button. IMU Batch Sample.

The “new DF Log” has been replaced with “IMU Batch Sample”. they do the same, and are in the same places as the wiki. Only the names have been changed to protect the innocent.

The “IMU Batch Sample” button generates no results for me.

The only button that works is “Run all IMU’s IMU1-3 MSG”.

It generates graphs in two of the six places.

Here’s a screenshot: Dropbox - fft.png - Simplify your life

Post your parameter file. Something is probably configured wrong. You only need batch sampling on the 1st IMU.

Thank you for helping me work through this. Here’s the .bin file I’m using:

You needed this set to gather the frequency data for setting up the Harmonic Notch filter:
I also notice you’ve got some very difference roll versus pitch settings…

Edu450 basic tuning params.param (1.1 KB)
You can apply this file as a reasonable starting point, it’s from a working EDU450 with 4 cell Lipo so check/change the voltages by pressing Alt-A in MissionPlanner (after applying this file) and just accept the battery voltage related settings.
Harmonic Notch is already configured and working in these params, but you might want to set
to verify that it is working as expected, or needs adjustment.

I just sent you a message under the “ALT-A Plug In” thread regarding your basic tuning parameters.

I sent you some questions seeking you further advice.

Can you please explain your comment “I also notice you’ve got some very difference roll versus pitch settings…” Are you comparing the parameters from my .bin file (my current parameters) and the parameters on your suggested basic tuning params list? If so - which parameters?

As I mentioned in my other message - I printed out your suggested tuning parameters, and compared each one with the parameters I have now. Indeed - some are quite different.

I also explained that I’ve completed a successful auto-tune, battery calibration and compass calibration - and that my EDU-450 carries quite a bit and may be a little heavier than some.

My copter has experienced some “wobble” in various instances - most notably after large yaw changes. The copter also wobbles quite a bit on the high-speed phase of the RTH descent. (I’d thought of just slowing that rate parameter.)

But if my PID’s and Filters are off - I certainly want to fix them - the safest way possible. I will make the change to INS_LOG_BAT_MASK so I can collect filter data.

Again - many thanks for your kind assistance!

From memory when I looked at your .bin file the pitch and roll PIDs were different but the EDU450 is very symetrical. Autotune with the payload could cause this.
All tuning and Autotune should be done with minimum takeoff weight and then you only need to adjust these to suit your payload:
ATC_ACCEL_P_MAX x (min_TOW / max_TOW)
ATC_ACCEL_R_MAX x (min_TOW / max_TOW)
ATC_ACCEL_Y_MAX x (min_TOW / max_TOW)

A well tuned EDU450 will drop like a stone from great height without any sign of wobble or instability, I think mainly due to the aerodynamic arms. So the fact you’ve got wobble in some cases also indicates some scope for better tuning. Their “sideways” performance in wind, or resistance to wind, is not quite as good because of the shape of those arms
Those params I gave you were also used (unchanged) on EDU450’s carrying a payload.

I replied in the Alt-A discussion too but definitely use the plug-in or spreadsheet to set your voltages, since the EDU450 params I supplied suited 4 cell Lipo (as previously mentioned)
If using 3 cell you could still start with my params (except voltage) then run Autotune with minimum takeoff weight just to be sure

Those parameters that @xfacta has provided you work very well on the EDU-450. I just tested them today on mine. I’ve been fighting the other side, where I think my build is lighter than normal so a few minor tweaks were required. Either way it’s been a great kit.

Here’s the first three. There should be seven more tomorrow.