# Revision history [back]

I think the warning says it all. I'm guessing the whole thing is this:

The root link base_link has an inertia specified in the URDF, but KDL does not support a root link with an inertia. As a workaround, you can add an extra dummy link to your URDF.

The fix is then to add an extra link (non-inertial) and joint to the top of the URDF file such that the new link is the reference for the rest of the robot. Something like:

<link name="base_footprint" />

<joint name="base_footprint_joint" type="fixed">