mecanum_drive_example not moving lateral a linear velocity in y

[javijurado]

Describe the bug
mecanum_drive_example not moving lateral a linear velocity in y

To Reproduce
See the video
https://github.com/user-attachments/assets/c1504160-fa40-4788-bcc7-4d28b0636907

Expected behavior
I expected to move lateral
Screenshots
If applicable, add screenshots to help explain your problem.

Environment (please complete the following information):

• Docker container running ros2 humble

Am I doing something wrong?

[github-actions]

This issue is being labeled as stale because it has been open 45 days with no activity. It will be automatically closed after another 45 days without follow-ups.

[github-actions]

This issue was closed because it has been stalled for 45 days with no activity.

[NickZhou11000]

The demo code for humble is not going to work for Ignition Gazebo Fortress, which is recommended for ROS2 Humble.
To make the simulation successful, you need to modify the urdf file test_mecanum_drive.xacro.urdf.

Apparently that Ignition Gazebo had changed the api for <fdir1>.
For Fortress and before, it use <fdir1 ignition:expressed_in='base_link'>1 -1 0</fdir1>
For Garden and after, it use <fdir1 gz:expressed_in='base_link'>1 -1 0</fdir1>

Following are demo code for Fortress and older:

<robot name="mecanum_vehicle" xmlns:xacro="http://www.ros.org/wiki/xacro" xmlns:ignition="http://gazebosim.org/schema">

  <gazebo reference='**_**_wheel'>
    <collision>
      <surface>
        <friction>
          <ode>
            <mu>1.0</mu>
            <mu2>0.0</mu2>
            <fdir1 ignition:expressed_in="base_link">1.0 -1.0 0.0</fdir1>
          </ode>
        </friction>
      </surface>
    </collision>
  </gazebo>

</robot>

Following are demo code for Garden and newer:

<robot name="mecanum_vehicle" xmlns:xacro="http://www.ros.org/wiki/xacro" xmlns:gz="http://gazebosim.org/schema">

  <gazebo reference='**_**_wheel'>
    <collision>
      <surface>
        <friction>
          <ode>
            <mu>1.0</mu>
            <mu2>0.0</mu2>
            <fdir1 gz:expressed_in="base_link">1.0 -1.0 0.0</fdir1>
          </ode>
        </friction>
      </surface>
    </collision>
  </gazebo>

</robot>

Don't forget the xmlns:ignition="http://gazebosim.org/schema" at the beginning

[christophfroehlich]

Thanks for pointing this out.

The demo code for humble is not going to work for Ignition Gazebo Fortress, which is recommended for ROS2 Humble.
To make the simulation successful, you need to modify the urdf file test_mecanum_drive.xacro.urdf.

I just don't understand the versions here, humble+fortress is the released combination, where the current URDF should be fine according to your snippets?

Do you mind opening a PR against the rolling branch, which will be backported to kilted and jazzy? on humble we would have to create a xacro if/unless branch or two separate URDF files.