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error in tf tutorial for diamondback

asked 2011-03-19 07:35:11 -0600

dan gravatar image

updated 2011-03-21 08:23:44 -0600

mmwise gravatar image

I think that there is an error in the tf/Tutorials/writing a tf broadcaster wiki for diamondback, but I want to check before I edit the wiki.

Specifically, on the page: Writing a tf broadcaster

In the launch file there is a reference to a package that does not come up in rospack find (turtle_teleop) and also two broadcast nodes are started, whereas the subsequent notes suggest that only one should have been. So the existing code is:

<launch> 
<include file="$(find turtle_teleop)/launch/turtle_keyboard.launch" />

<node pkg="learning_tf" type="turtle_tf_broadcaster"
      args="/turtle1" name="turtle1_tf_broadcaster" />
<node pkg="learning_tf" type="turtle_tf_broadcaster"
      args="/turtle2" name="turtle2_tf_broadcaster" />

</launch>

I suggest this instead:

<launch>
<!-- Turtlesim Node-->
<node pkg="turtlesim" type="turtlesim_node" name="sim"/>
<node pkg="turtlesim" type="turtle_teleop_key" name="teleop" output="screen"/>
<!-- Axes -->
<param name="scale_linear" value="2" type="double"/>
<param name="scale_angular" value="2" type="double"/>

<node pkg="learning_tf" type="broadcaster_tf"
      args="/turtle1" name="turtle1_tf_broadcaster" />
<node pkg="learning_tf" type="turtle_tf_broadcaster"
      args="/turtle2" name="turtle2_tf_broadcaster" />

</launch>
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2 Answers

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answered 2011-03-20 08:55:27 -0600

dan gravatar image

Based on Melonee's comment that the tf tutorials have not been updated for diamondback, I implemented the changes on the wiki. Thanks for the help to get it right.

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Thanks Dan.
tfoote gravatar image tfoote  ( 2011-03-20 09:19:33 -0600 )edit
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answered 2011-03-19 07:44:23 -0600

dornhege gravatar image

updated 2011-03-19 07:46:27 -0600

Actually the text says that it should be like this.

The idea is the following: A turtle_tf_broadcaster broadcasts the tf for the turtle it got as a param.

So spawning multiple ones is OK, but they will only broadcast tf for their turtle. The turtlesim itself should come up with one turtle and you should see tf for this turtle only.

The turtle_teleop might be here: ros-cturtle-joystick-drivers-tutorials

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Comments

oops, I didn't mean to take out the second turtle_tf_broadcaster; thanks for catching that; I fixed the suggested code. You also make a good point that it is not broken in cturtle, so I edited the post to reflect that as well. However, I think that the tutorial is broken in diamondback because turtle_teleop apparently doesn't exist in diamondback.
dan gravatar image dan  ( 2011-03-20 06:31:39 -0600 )edit
I do have a turtle_telerop in diamondback. Didn't test the tutorial though.
dornhege gravatar image dornhege  ( 2011-03-20 06:47:19 -0600 )edit
dan is correct teleop_keyboard got move to turtlesim in the last release to make it easier on new users. the tf tutorials haven't been updated to reflect the recent release.
mmwise gravatar image mmwise  ( 2011-03-20 08:01:15 -0600 )edit

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Asked: 2011-03-19 07:35:11 -0600

Seen: 315 times

Last updated: Mar 20 '11