URDF's floating joint not working in Gazebo

Hi,

I am trying to run a simulation on Gazebo based on a URDF script. I want the robot to move freely in the environment.
How do I connect the base-link to the world?

  • Using a floating joint between the base link and the world is being converted to a fixed joint by Gazebo thus preventing robot from moving: [WARN] Converting unknown joint type of joint ‘<joint_name>’ into a fixed joint

  • Not using a joint between the base link and the world doesn’t work since the inertia of the base link will be ignored: [WARN] The root link vertical_link has an inertia specified in the URDF, but KDL does not support a root link with an inertia.

How can I overcome this? I want the robot to move freely but to keep inertia for the base link.

Thank you!