Visualizing continuous and revolute joint types in rviz

Question

When creating a URDF file for a robot with a head on a pan and tilt mechanism, whenever I try to use a joint type "continuous" or "revolute" in a manner similar to that shown in the tutorials the model is displayed within Rviz as a disorganized jumble. If I change the joint type to "fixed" then the model displays normally. The model also seems to check out ok using check_urdf, and no URDF errors show up when Rviz is loading. This seems to be a bug, since the same thing happens with the tutorial file 06-flexible.urdf

I'm using the current cturtle full binary installation on Ubuntu 10.10.

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Originally posted by JediHamster on ROS Answers with karma: 995 on 2011-02-19

Post score: 1

Answer 1

For non-fixed joints you need some source that publishes the joint states, otherwise the model cannot be displayed correctly, as the state of the joints is unknown.

A simple launch files for testing a URDF model in rviz using the joint_state_publisher looks like this:

<launch>
<param name="robot_description" command="$(find xacro)/xacro.py $(find yourrobot_urdf)/yourrobot/robot_base.urdf.xacro" />
<param name="use_gui" value="True"/>
<node name="joint_state_publisher" pkg="joint_state_publisher" type="joint_state_publisher" ></node>
<node name="robot_state_publisher" pkg="robot_state_publisher" type="state_publisher" />
<node name="rviz" pkg="rviz" type="rviz" />
</launch>

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Originally posted by Stefan Kohlbrecher with karma: 24361 on 2011-02-19

This answer was ACCEPTED on the original site

Post score: 4

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Original comments

Comment by JediHamster on 2011-02-19:
Ah, ok, that could be it!

Comment by Yantian_Zha on 2014-04-21:
Should I change robot_description to others? I got error "Cannot load command parameter [robot_description]: ...". I'm using Groovy. Thanks!

Comment by Stefan Kohlbrecher on 2014-04-21:
Hard to say what is wrong in your case without more information. You should probably create a new question with a detailed problem description.