"world" frame does not exist in tf tree when launching gazebo simulation

Question

I'm trying to work with sjtu drone simulator (https://github.com/NovoG93/sjtu_drone).

I'm using ROS2 humble, Gazebo 11.

When I launch the program, using:

ros2 launch sjtu_drone_bringup sjtu_drone_bringup.launch.py

everything is initiating and I manage to move the drone using its teleope window.

The problem is, the simulation doesn't have any reference frame, and the "higher" frame is the one located in the urdf.xacro file which is "base_link"

In previous simulations I used, both in ROS and ROS2, the Gazebo simulator used to have some reference frame to describe the robot's positioning according to it. Creating a new "world" frame in the URDF and using a static_tf_broadcaster is not an option here, since I want the drone to move.

How can I solve this problem?

Answer 1

As I do not know details, here are very general things:

1. Make sure gazebo gets the world (you can look at examples at my robotics.snowcron.com)
2. Make sure there is odometry frame. Odometry is a "connection" between steady "world" and moving robot. For example, in a wheeled robot, some kind of a publisher node publishes it.
3. Make sure world and odom are connected using static transformation - on my site, see any example for multiple bots, for example, but generally, it is just few lines.