Throttle Based Dynamic Notch Filter

ArduCopter
1

Hello fellow enthusiasts,

I’m relatively new to configuring a throttle-based dynamic notch filter, and I could use some guidance from those with more experience in this area. I’ve been working on setting up my system and reviewing the logs, but I’m not entirely sure if I’m on the right track. I would be extremely grateful if someone could take a look and provide some feedback.

Here’s a bit about my setup:

I recently made my initial attempt at configuring the dynamic notch filter using the specified parameters. However, I’m uncertain about the results. If anyone can share their insights, I would greatly appreciate it.
1st Test:
Logs

image
image1920×1029 129 KB

Parameters:
INS_LOG_BAT_MASK = 1
INS_LOG_BAT_OPT = 4
Observed Motor Center frequency is at 100 Hz

2nd Test:
Logs

image
image2598×1057 360 KB

INS_LOG_BAT_MASK = 1
INS_HNTCH_MODE = 1
INS_HNTCH_ENABLE =1
INS_HNTCH_REF = 0.203
INS_HNTCH_FREQ = 100Hz
INS_HNTCH_BW = 50Hz
INS_HNTCH_FM_RAT = 0.8

Your help would be invaluable to me as I continue to learn and improve my setup. Thanks in advance for any assistance and advice you can offer.

2

Use these:
image

for this:

image
image1207×447 42.6 KB

You’ve got something going on there at about 55Hz, so check for anything that could be vibrating and wobbling around, like GPS mast.

Just leave these set all the time, I havent seen it cause an issue yet:
image
That way if you suspect a new vibration, the logging is already there.

You can use ARMING_CHECK,1 and ATC_THR_MIX_MAN,0.5

1 Like
3

Hi Shawn,

Thanks for your previous reply. I have a couple of follow-up questions regarding the notch filter values and the test results.

Did you mean to suggest using the FIRST NOTCH FILTER values you shared for our next flight to reduce the noise at 100 Hz?

In the test we conducted, we observed the amplitude dropping to -500 and -800. I’m curious if this drop in amplitude is within an acceptable range, or if it indicates any phase lag issues?

image
image2566×1048 358 KB

Logs

Additionally, I conducted one more test and attached the images below:

image
image2567×1037 361 KB

Logs
However, in the mission planner’s FFT >> IMU BATCH sample, I’m seeing unusually high amplitudes. Here also amplitude dropping roughly to -900 and -1500. Could you help me understand why this might be the case?

If you need any logs from the test, please let me know, and I’ll be happy to provide them.

Thanks in advance for your assistance.

4

Hi Shawn,

Appreciate your response! Following your advice, I’ve carried out two tests with the parameters you recommended.
image
ATC_THR_MIX_MAN,0.5

The first test involved setting the Gyro filter value to 20, while the second test used a Gyro filter value of 60.

Test 01:
Logs

Gyro20
Gyro201207×448 15.1 KB

Test 02:
Logs

Gyro60
Gyro601199×450 17.3 KB

I’d greatly appreciate it if you could review this and provide feedback on whether my approach was correct.