A question about using tf . [closed]

asked 2014-08-11 08:24:50 -0500

Lau
45 ●6 ●9 ●13

updated 2014-08-11 09:30:14 -0500

Hello ! I have a LIDAR HDL-32E on my car , and I load a car model in the rviz and display the point cloud . The "frame_id" of the LIDAR is "velodyne" and the car base's is "base_link" . Then I do these steps :

launch the LIDAR and publish the topic velodyne_pointclouds whose type is sensor_msg::PointCloud2 ;
run the tf_broadcaster , transform the frame between velodyne and base_link;
launch the car model and display in rviz .

But point cloud did not show out ater I add the PointCloud2 in the left window . And it informs an Error :

For frame [velodyne]:Frame [velodyne] dose not exist .

Maybe I misunderstand the tf and the relationship between reality and simulation . Can tell me what should I do ?

edit retag flag offensive reopen merge delete

Closed for the following reason question is not relevant or outdated by tfoote
close date 2018-05-17 18:19:49.240886

Comments

Have you tried visualizing or echoing your tf tree to verify that the transforms are actually being broadcast?

Tom Moore ( 2014-08-11 08:32:49 -0500 )edit

How to do this step ?

Lau ( 2014-08-11 09:39:30 -0500 )edit

add tf in rviz left window or use rosrun tf view_frames ( http://wiki.ros.org/tf#view_frames )

bvbdort ( 2014-08-11 10:08:42 -0500 )edit

I ran the tf view_frames and it does broadcast . But still no point cloud displayed in rviz .

Lau ( 2014-08-11 10:38:34 -0500 )edit

still the same error or different ?

bvbdort ( 2014-08-11 10:58:01 -0500 )edit

What have you set as fixed frame in RVIZ? I don't know the tf_broadcaster, but stuff like that is usually done with the static_transform_publisher: http://wiki.ros.org/tf#static_transfo...