Missing connection between /map and /base_link

transform

asked 2013-04-29 07:01:07 -0600

mharms
17 ●6 ●7 ●10

updated 2013-05-02 04:52:55 -0600

Hi at all,

I am very new to ROS. After working out the tutorials and the Book "ROS by example" I got the following error, when running rviz with my personal robot.model:

> Waiting on transform from /base_link to /map to become available before running costmap, tf error: Could not find a connection between '/map' and '/base_link' because they are not part of the same tree.Tf has two or more unconnected trees. <<<

In my urdf File I have got only base and a link to a Laser_link, which is not used yet.

I looked through many files comparing mine with the turtlebot-files. I dont understand where the link between base_link and map is made, I believe it is in the move_base but I really dont know. If it helps I can send the content of files but dont know which one.

Hope that someone here can help me.

Thanks and best wishes

Michael, Berlin, Germany

EDIT

Sorry for asking again. I get the error in the console when running roslaunch myrobot fake_turtlebot.launch, not in rviz, si the error message doesnt depend on my settings in rviz. I do this too find out and compare my file with turtlebot-tutorial, why my robot isnt operating correct, eg. when I want to run move_base and click in the map to define a goal. When I run myrobot myrobot.lauch the rviz shows the thin blue line as path to the goal correctly, but is moving somewhere in the wrong direction with flashing the red lines.

edit retag flag offensive close merge delete

add a comment

2

answered 2013-04-29 08:36:14 -0600

rohan
358 ●8 ●12 ●15

updated 2013-04-29 08:37:03 -0600

In RViz in the global options you can choose fixed frame. Is it map? Try choosing "base_link" as your fixed frame. You can have a look at the image below and that is my robot model in rviz.

https://portal.bitcasa.com/send/bbb86466824c8ef50a8b4c01f34bd3fde55d50a9c1bf27c9588f4350e7039ee9/39b88c7ecd95c50b44c0d3fc722d96a1dba01e2989a07e4c32586c9fdfd1986a (link text)

edit flag offensive delete link

Comments

Thank you very much, for your rapid help and the provided image. Yes, it is set to /map. I will try changing this tomorrow when I am back to my work.

mharms ( 2013-04-29 09:49:35 -0600 )edit

add a comment

3

answered 2013-04-29 15:18:30 -0600

weiin
2268 ●26 ●46 ●65

Take a look at http://ros.org/reps/rep-0105.html#coordinate-frames to understand the various frames used.

Use rosrun tf tf_monitor or rosrun tf view_frames to see if the required frames are being broadcast.

In general, the /map (to /odom or /base_link) frame is broadcast by a localization node (eg. amcl or gmapping). The /odom (to /base_link) frame is broadcast by an odometry producing node (eg. from your wheel encoders or robot_pose_ekf).

edit flag offensive delete link

add a comment

Missing connection between /map and /base_link

EDIT

2 Answers

Comments

Question Tools

Stats

Related questions

Missing connection between /map and /base_link edit

EDIT

2 Answers

Comments

Question Tools

Stats

Related questions

Missing connection between /map and /base_link