Pixhawk 2.1 vibration problems / oscillation

Hey,

i have set up an selfmade air frame with the new pixhawk 2.1. The flight is very unstable and i cannot really start. I increased the stiffness but there is no improvement on raw accel values. Are this values the result of wrong PIDs? Or is the mechanical part the problem? Or is the Pixhawk defect?

Pixhawk 2.1: https://logs.px4.io/plot_app?log=f3621ac4-db1a-45fd-ad4d-ddf8f94a510e

EDIT:
I tested a Pixhawk 2. He also oscillates but not so much.
Pixhawk 2: https://logs.px4.io/plot_app?log=4bd64cf0-cea0-4391-b919-f6ca71714e75

I hope somebody can have a look into it.

Thx

Hi ToblasM,

Do you put moss/rubber between your Pixhawk and your frame’s UAV ? Cause IMU are vibrations-sensitive.
Also, your GPS is near to your autopilot ? I don’t think so seen the thrust and magnetic field’s graphs looks good.

Thomas

Thanks for your answer. There is no GPS installed actually. rubber is installed.

what is the behaviour with totally wrong PIDs? can it cause such a vibration?

Yes but I talk about my experience, I’m quiet new on UAV’s world and I get similar problem few weeks ago.

Yes, with PID an overevalued Integral gain is knowned for create oscillations.
Please, see this :

https://docs.px4.io/en/advanced_config/pid_tuning_guide_multicopter.html

If you don’t know anything about PID, don’t do PID tuning too quickly, take your time.

Thomas