Correct way to integrate ZED2i in the urdf and setup ZED odom and map frames + GNSS fusion - ROS2

Software
1

Hello,

I’m having issues figuring out the correct setup for my multiple ZED2i cameras in an autonomous mobile robot, that also mounts 4 lidars.
I’d like to understand what’s the standard for it, as the documentation doesn’t cover the full scenario i have.

URDF:
I have two ZED2i cameras, one mounted at the front and the other at the back of the vehicle. The robot’s base_link serves as the reference frame.

Expected Configuration:

  • The front camera is supposed to publish /odom and /map frames, with /odom resulting from the fusion of VIO, IMU, and GNSS RTK.
  • The rear camera doesn’t participate in pose tracking.
  • The robot’s frame tree should follow the REP105 convention, with the structure (utm) -> map -> odom -> base_link -> … -> zed_front_camera_link.

I’ve tested several setups and am currently able to successfully fuse the GNSS RTK data and integrate the cameras with the desired functionalities.

However, I’m encountering issues when I try to properly reference the /odom and /map frames to the base_link, as they should be used for algorithms from slam_toolbox and nav2.
These frames are still attached to the zed_front_camera_link. Even after hardcoding the mBaseFrameId in zed_camera_components_main.cpp to base_link, I can only reference /odom (and the pose vector) to it, while the map remains fixed to the front camera position. Changing the initial_base_pose parameter doesn’t seem to resolve the issue for me.

I can explain further in subsequent replies and share tf2_trees and images, but for now, I just wanted to understand how you envision integrating the camera on a complex robot with pose tracking and GNSS fusion capabilities.

Thank you

2

Hi @foiegreis
Welcome to the StereoLabs community.

This section of the ROS 2 documentation

and this tutorial on the Nav2 website
https://docs.nav2.org/tutorials/docs/integrating_vio.html
will help you solve your doubts.

3

Hi Myzhar,

thank you for your reply. Of course I’ve checked the documentation before writing here in the forum.
The documentation doesn’t cover my full problem. As an example, the zed integration post supposes that with ZED pos_fusion (use_zed_localization) the reference frame of the robot would become zed_camera_frame.
Having a tree with the zed camera as reference is something i would not consider for my application.

Can we dive into the setup in deep?

Thank you

4

In this case, you must disable publish_tf for all the cameras and provide the correct TF chain as described here.

You can use the disable_tf parameter of the multi-camera launch file.