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Hi!

I'm installing the navigation stack in my own simulated robot, but when I try to launch I gave the next problem:

"Waiting on transform from base_link to /map to become available before running costmap, tf error: Frame id /base_link does not exist!"

Searching a little I found that normally the transform broadcaster of one robot publish 3 tf (odom->base_link_offset base_link_offset->base_link base_link_ofsset->baser_laser_link) but I'm not sure for what is exactly each one and what are the necessary for make the navigation stack run. By other hand, my robot only publish one transform trought the chassis->base_laser_link (as explained in this tutorial), so I think that there is the problem.

Can anyone help me?


Originally posted by mbj on ROS Answers with karma: 197 on 2011-05-09

Post score: 0

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The frames necessary to run the navigation stack can vary based on its configuration. You might, for example, run the navigation stack in an odometric frame which would mean that you'd need something like "odom -> base_link -> base_laser" at minimum. However, if you run with a static map or SLAM, you'd want a tf tree that looks something like "map -> odom -> base_link -> base_laser." At the very least, the navigation stack requires some sort of global frame to work properly. So, setting the global_frame parameter of the costmap to something like "base_link" wouldn't make much sense.

If you were to use the configuration described in the Setup and Configuration Tutorial, 4 frames are required: "map->odom->base_link->base_laser."


Originally posted by eitan with karma: 2743 on 2011-06-09

This answer was ACCEPTED on the original site

Post score: 4

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