[ros-users] Weirdness in URDF tutorials

[Wim Meeussen]

> I remember that robot_state_publisher does not publish any transforms unless
> there is at least a revolute or prismatic joint in your urdf... Wim, can you
> confirm this?

If your urdf only has fixed joints, the robot state publisher will
automatically publish transforms to tf at the specified frequency,
even when nothing gets published on the joint_states topic. As soon as
you have at least one non-fixed joint, you need to publish joint
states to have the robot state publisher to anything.

The current version of the robot state publisher however has a bug in
the case all joints are fixed joints. It does not assign the correct
timestamp to the tf messages. There is an unreleased fix in trunk
<http://www.ros.org/wiki/robot_model/ChangeList/1.3>.  I created a
ticket as a reminder to push out a release of robot_model
<https://code.ros.org/trac/ros-pkg/ticket/4658>

Wim






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Wim Meeussen
Willow Garage Inc.
<http://www.willowgarage.com)