Tuning the copter by applying FFT notch filter and second as throttle

ArduCopter Copter 4.6
1

Hi everyone,

I’ve been tuning my drone and wanted to get some advice to make sure I’m going in the right direction.

Setup details

  • Flight Controller: CUAV X7+
  • Frame MTOW: ~7 kg
  • Motors: T-Motor 7005 230KV
  • Props: 24 inch
  • Firmware: ArduCopter 4.6.2

Issue
Initially, I faced some tuning issues related to oscillations. I noticed noise peaks in the logs, so I applied notch filtering — first tried a regular notch, then configured FFT-based notch and throttle-based notch as static (fixed frequency).

After setting these up and re-tuning (auto-tune + manual refinement), the drone now performs very well — stable, responsive, and efficient.

However, I’d like to confirm if my setup is correct and best practice:

  1. Once tuning is complete and everything flies well, should I keep FFT enabled permanently or can I disable it and just keep static notches?
  2. Is there a recommended way to verify that my notch filter settings (center frequency, bandwidth, gain) are optimal?

I just want to make sure I’m not missing anything before finalizing this configuration.

Thanks in advance for your suggestions!

2

Set these parameters and do a simple hover flight for a minute or so:
INS_LOG_BAT_MASK,0
INS_LOG_BAT_OPT,0
INS_RAW_LOG_OPT,9

3

Please have a look on the hover flight with above values.

4

I don’t see that you changed any of those parameters in that log.

5

Please check this today I did hover test with above suggested param.

6

Disable the 2nd notch and delete the 3rd harmonic of the 1st notch and it looks OK.

I would replace the FFT notch with a Throttle referenced Notch and disable the 2nd notch:

Throttle notch
Throttle notch336×523 114 KB

After completing the Notch filter configuration disable Raw Logging as it will produce huge logs.

7

Initially I tried with throttle notch but the tuning was not happening and producing poor tuning. Then i moved with FFT tune where the results are positive. May I know is there any problem that FFT causing for long run.

8

If its configured well then it works well. I use this as a “clean-up” notch typically as well as ESC and static notches.