Hi everyone,
I’m currently trying to set up another drone for our lab to use Motion Capture (Vicon) data without any other additional sensor fusion (GPS, Mag, Baro disabled). What has worked before with older versions of PX4 (Versions 1.13 and 1.14.) doesnt work for the latest stable release, which leaves me confused. For explanation: We have multiple drones with different px4-versions and onboard PCs. All are working with the same onboard software (ubuntu 22, vrpn_mocap, MicroXRCEAgent, ros2 python node for transition between msg-types of px4 and MoCap)
What I am trying to do:
Set up a drone with a Pixhawk 6X (Version 1.15.4) connected via Ethernet to companion PC (RPi 4), using vrpn_mocap client for MoCap data, MicroXRCEAgent for communication between RPi and Pixhawk and a small python node to publish the MoCap data to the “fmu/in/vehicle_visual_odometry” topic. This has worked well for multiple other drones running on other px4-version (for example 1.14.0).
Whats wrong?
The communication seems to work just fine (I can publish and subscribe to topics of the Pixhawk). Also the MoCap data is used by the PX4 software in some way at least, which i can see in the “/fmu/out/vehicle_odometry” topic. The odometry shows the MoCap data, if the drone is standing still. However, when I move the drone, the position estimation ends up “overshooting”, slowly regaining the correct MoCap position after 2-3 seconds of holding the drone in place. The MoCap position is published with 250 Hz and is precise all the time.
The behaviour can be found in this flight log, where i manually moved the drone from 0/0 for approx. 2m, stopping for a bit and then moved it back to the origin.
What did I try?
First of all, I copied the software and ekf2 parameters from other working drones in our lab. Since I dont have a backup of the flight controller software, i installed older stable versions, but the new drone still shows the same behaviour.
Further, I flashed to 1.15.4 again and tried several different parameter settings as mentioned in this for the current stable version. I did not succeed, which leaves me wondering, if I am just not capable of finding the right settings or if there has been some fundamental changes to the whole setup or the EKF2, which would cause such a problem. Hardware should not be a problem - I tried multiple cables and even another FC, just to be sure.
If anyone has a fix for this, a working parameter setup or recently had the same problem, I’d greatly appreciate any help.
Thanks in advance!