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Can you @dornhege mark my answer as correct? I dont have karma > 25

Thanks for the reply @dornhege The tf chain was perfect. The problem is explained below. Feel free to ask if I havent explained well.

The error was in the odometry sent to 'message_to_tf' node. Message_to_tf is meant to provide intermediate transforms between /base_link and /odom. Odom is my odometry without z value so it was moving, but base_link wasnt. Why? I was passing to 'message_to_tf' and odometry message identical to ground_truth published by Gazebo but with x,y position and rotation set to 0. The problem is that z rotation wasnt 0 so odom moved in yaw but base_link kept static.

So the answer is: In the following scenario (quadrotor flying), being /odom the odometry without z-value, the odometry message that we must pass to 'message_to_tf' to obtain intermediate transforms between /odom and /base_link (defined in the urdf file) must have only the z component of position and all the remain values to 0 (keeping quaternion normalized)

Yes, they are parent->child. There are any more frames, its the complete chain

The answer to this question is not simple. It depends on how you want your frames and what transforms are you doing and how are you doing them. Each case will require different solutions.

I recomend to make a draw about your frames and reference axes, what you want, what you have and asking yourself if the transformations you are doing have any sense by themselves.

I have the following scheme in simulation enviroment with Gazebo and Rviz: laser_frame -> base_link -> base_stabilized -> base_footprint -> odom -> map -> world

laser_frame to base_link is provided by robot_state_publisher looking up in the urdf file

base_link -> base_stabilized -> base_footprint -> odom is provided by a 'message_to_tf' node that takes ground_truth topic with z axis and rotation to publish this transformations

odom -> map is provided by a mapper node setting up the transforms in x-axis and y-axis

map -> world is provided by a node doing a static/fixed transform

In Rviz we have as fixed frame and target frame the /world frame. World is fixed, map is fixed refering to world, odom is moving in x,y,z and rotation refering to map BUT base_footprint, base_link and therefore laser_frame arent moving. They keep as they started.

How can I fix it? What am I missing?

Thanks

I have the following frame transformation chain: laser_frame -> base_link -> base_stabilized -> base_footprint -> odom -> map -> world

Where

• laser_frame is where the scans are generated
• odom is the odometry regarding the map
• map is where the 2D map is created based on scans
• world is the frame in the middle of the stage, what is meant to be (0,0,0) and the very first coordinate axis

I want the map to be created over the world while scans/world/map moving regarding the quadrotor. I mean something intuitive, the quadrotor moves inside the stage so rviz must show how the stage (world, scans and map) move relative to it, keeping it in the center of view, fixed.

What must be the fixed frame? What must be the target frame? Why? Must I do some weird transformation or it's just simply the setup?

Very thanks ahendrix, now its more clear! I did not find anything relevant on the web :(

I dont know what 'ground truth' means. My project use a 'ground truth to tf' node and gazebo publish some 'ground truth' topic that seems an Odometry message.

What does it means?

What is it intended for?

Thanks for the reply ahendrix. What absolute origin of coordinates does groundtruth refers to in gazebo? And what should be in a real SLAM enviroment? The exact position known by the observer? Do you know what i mean?