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No transform from [anything] to [/base_link]

asked 2011-03-09 20:48:25 -0600

mbj gravatar image

updated 2011-03-11 00:18:29 -0600

kwc gravatar image

Hi.

I'm trying to learn how to build a visual robot model from scratch with this tutorial.

When I run the first shape it works fine, but when I try to run the others shapes rViz show messages like these:


base_link: Transform OK

box: No transform from [box] to [/base_link]

gripper_pole: No transform from [gripper_pole] to [/base_link]

head: No transform from [head] to [/base_link]

left_back_wheel: No transform from [left_back_wheel] to [/base_link]

...

right_tip: No transform from [right_tip] to [/base_link]

URDF: URDF parsed OK


I have readed all about the topic, but I don't find any solution. This is a problem in the tf? I'm copy-pasting the code of the robots and following step by step the tutorial, where is the problem?

Sorry for my poor english and thanks!

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answered 2011-03-09 21:51:50 -0600

updated 2011-03-09 21:53:23 -0600

If you have any movable joints these need to be published. There is a package called joint_state_publisher which you can use (not part of the ROS install).

http://www.ros.org/wiki/joint_state_publisher

Build that package, then create a launch file similar to the following:

 <launch>
   <param name="robot_description" textfile="myrobot.urdf" />
   <arg name="gui" default="False" />
   <param name="use_gui" value="$(arg gui)"/>
   <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>

You can then launch as follows:

roslaunch myrobot.launch gui:=true

If you're not using joint_state_publisher then you will need to publish the movable joint states using sensor_msgs:JointState. One mistake I made with this is that all joint positions should be published at the same time by adding them to the JointState object. If you try to publish them separately then problems similar to the above can occur.

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Asked: 2011-03-09 20:48:25 -0600

Seen: 11,954 times

Last updated: Mar 09 '11