X copter with oscillation around its diagonal

ArduCopter Copter 4.4
, ,
1

Hello,
We have a drone that was really stable for several flight and lately start oscillating on a diagonal with a mix of pitch and roll oscillation.
For exemple for the first flight we had oscillation on the two CCW motors and nothing on the CW motors and it switched for the second flight.
Some quick info about the drone :see_no_evil:

  • 170kV motors
  • 12S
  • 22 inch props
  • Diag about 1m
  • 8kg for the tests

Log :

If you have any idea.

Thanks for you help !

2

I keep digging.
Oscillations seems to be auto-amplifided. I suspect an issue with vibration but not an expert.

Capture d’écran 2024-03-29 à 15.22.35
Capture d’écran 2024-03-29 à 15.22.351920×804 140 KB

Capture d’écran 2024-03-29 à 15.22.43
Capture d’écran 2024-03-29 à 15.22.431920×824 100 KB

Capture d’écran 2024-03-29 à 15.22.50
Capture d’écran 2024-03-29 à 15.22.501920×723 80.4 KB

Capture d’écran 2024-03-29 à 15.23.10
Capture d’écran 2024-03-29 à 15.23.102528×1840 438 KB

Capture d’écran 2024-03-29 à 15.23.23
Capture d’écran 2024-03-29 à 15.23.232470×1174 233 KB

Capture d’écran 2024-03-29 à 15.24.48
Capture d’écran 2024-03-29 à 15.24.482544×1884 451 KB

Capture d’écran 2024-03-29 à 15.25.05
Capture d’écran 2024-03-29 à 15.25.052396×1460 284 KB

Capture d’écran 2024-03-29 à 15.25.19
Capture d’écran 2024-03-29 à 15.25.192436×988 141 KB

Capture d’écran 2024-03-29 à 15.25.28
Capture d’écran 2024-03-29 à 15.25.282374×1062 185 KB

The drone flew for about 10 hours before having this issue so I suspect a mechanical reason.
What are yours thought about it ?

Thank you !

3

I’m doing a workshop on tuning drones for professionals on the 16 of April. Want to join?

I’ll also be presenting the ArduPilot methodic configurator GUI software:

4

Oh yes it would be great ! Thanks @amilcarlucas for the invitation.

5

Still investigating my issue.
Reducing the MOT_THST_EXPO has clearly an impact the drone behavior and its “capability” to start these oscillations. (ESC T-MOTOR 60 A 12S)
For now I have

MOT_THST_EXPO = 0.2
MOT_PWM_MIN = 1100

There you can find some videos of this behavior :
IMG_2369.MOV - Google Drive (good flight)
IMG_2370.MOV - Google Drive (oscillation)