PID values from 3.8 to 4.1 on clean install

I’ve gone from an APM 2.8 to a Pixhawk 4 and copied my configuration file over. The plane flew very well on auto mode on 3.8.

The APM was running 3.8 and the Pixhawk 4 is on 4.1.5.

I see the PID value calculation formulas have changed. Do I need to manually change my PID values as I didn’t upgrade to 4.1 with them loaded or will I be OK on my original values?

Thanks

Normally if you upgrade to 4.1 the pid values will automatically be converted. I don’t think it’s a good idea to take your settings from 3.8 and dump them in to 4.1 because the PID controller changed with the release of 4.1.

Hi @anparkinson,

More details of the new PID-controller can be found here: PID control

At the end of the first post you will find a conversion tool to translate the old PID’s to new PID’s.
PID converter

If I remember correctly there were a lot of other major changes from pre-AP3.9 versions.
I would be very careful just “cherry-pick” a few well understood param’s for the new plane.

I would start from default parameters with 4.1.6 and configure and tune as if it’s a new craft.

you have two methods:

  1. if you have 3.8 installed and install 4.1.x then it will auto-update your PID values to be equivalent
  2. you could use this conversion tool to convert: ArduPilot Plane 4.1.x PID Calculator

After updating I suggest you use the new fixed wing autotune to improve your PID tuning