Issue with position-mode on large H-8 multicopter

PX4 Autopilot Configuration & Flight Modes ⚙️
1

Hi,
We are building a large-size prototype of a multicopter with a H-8 motor configuration.
We are now in the process of tuning the PID controllers, however we have been having some issues when flying in position mode.
With the P gain for the Roll-Rate controller set to a value of 0.22 we observe a good behavior when flying in stabilized mode, however after switching to position mode the multicopter starts to oscillate increasingly.
If we increase the P gain for the Roll-Rate controller up to 0.37, then the multicopter becomes stable in position mode but we can observe high vibrations on the multicopter.
Here are the logs for both flights:
Roll Rate Controller settings (P:0.22, D:0.003, I: 0.2)
https://logs.px4.io/plot_app?log=2f878be6-b0cc-448b-a7d5-a51742e93850

Roll Rate Controller settings (P:0.37, D:0.003, I: 0.2)
https://logs.px4.io/plot_app?log=fb95a1bf-33cc-4e06-b235-bd402efbb559

I will appreciate any help.
Regards,

Luis Zárate

2

Have you gone through docs for tuning? Are your steps small for tuning as well? Big steps will drift you too much from stability.