Ask Your Question

Problem with robot_localization transforms

asked 2017-11-01 15:02:49 -0500

jauer gravatar image

updated 2017-11-01 15:03:51 -0500


I am experimenting with robot_localization and amcl. I use a simulated turtlebot 3 which is in the /robot1/ namespace and has robot1_tf as tf-prefix.

I use a robot_localization ekf for the robot1_tf/odom frame and a separate one for the map. The problem here is that this map ekf always uses robot1_tf/map as map frame. But I need map as map-frame. I tried various combinations but that didn't change it.

My launch file looks like that:

<group ns=robot1">
    <param name="tf_prefix" value="robot1_tf" />

    <node pkg="robot_localization" type="ekf_localization_node" name="ekf_se_odom" clear_params="true">
          <rosparam command="load" file="$(find tb3_lidar_navigation)/params/odom_ekf.yaml" />

    <node pkg="robot_localization" type="ekf_localization_node" name="ekf_se_map" clear_params="true">
      <remap from="odometry/filtered" to="odometry/filtered_map"/>
      <rosparam command="load" file="$(find tb3_lidar_navigation)/params/map_ekf.yaml" />

    <!--- Run AMCL -->
    <include file="$(find tb3_lidar_navigation)/launch/amcl.launch.xml">
          <arg name="robot_ns"       value="$(arg robot_ns)"/>
          <arg name="robot_tf"       value="$(arg robot_tf)"/>
          <arg name="initial_pose_x" value="$(arg initial_pose_x)"/>
          <arg name="initial_pose_y" value="$(arg initial_pose_y)"/>
          <arg name="initial_pose_a" value="$(arg initial_pose_a)"/>
          <arg name="tf_broadcast"   value="false"/>

The config file for the map_ekf looks like that:

frequency: 30
sensor_timeout: 0.1
two_d_mode: true
transform_time_offset: 0.0
transform_timeout: 0.0
print_diagnostics: true
debug: false    

map_frame: map
odom_frame: odom
base_link_frame: base_footprint
world_frame: map

odom0: odom
odom0_config: [false, false, false,
               false, false, false,
               true,  true,  true,
               false, false, true,
               false, false, false]
odom0_queue_size: 10
odom0_nodelay: true
odom0_differential: false
odom0_relative: false

pose0: amcl_pose
pose0_config: [true,  true,  false,
               false, false, false,
               false, false, false,
               false, false, false,
               false, false, false]
pose0_queue_size: 10
pose0_nodelay: true
pose0_differential: false
pose0_relative: false

imu0: imu
imu0_config: [false, false, false,
              true,  true,  false,
              false, false, false,
              true,  true,  true,
              true,  true,  true]
imu0_nodelay: true
imu0_differential: false
imu0_relative: false
imu0_queue_size: 10
imu0_remove_gravitational_acceleration: true

use_control: false

Does anybody know how I can change the map frame? Thanks!

edit retag flag offensive close merge delete


Try with a forward slash in front, to tell the node that it is an absolute name: /map.

ufr3c_tjc gravatar image ufr3c_tjc  ( 2017-11-01 16:56:02 -0500 )edit

Thank you! I already tried that and it resulted in the same tf-tree as without slash. So this is no solution.

jauer gravatar image jauer  ( 2017-11-02 03:18:49 -0500 )edit

Maybe remove the tf_prefix parameter and put the frames as robot1_tf/odom and map into the YAML?

ufr3c_tjc gravatar image ufr3c_tjc  ( 2017-11-02 16:49:04 -0500 )edit

Same again. Is it possible that the filter somehow also uses the frames which are used in the subscribed sensor topics?

jauer gravatar image jauer  ( 2017-11-03 03:43:25 -0500 )edit

1 Answer

Sort by ยป oldest newest most voted

answered 2018-01-24 04:06:11 -0500

Tom Moore gravatar image

You have tf_prefix set. Simply removing it from your launch file might not help, unless you start a new ROS master afterwards, or manually delete the tf_prefix parameter. I would stop your ROS master, remove tf_prefix, then run everything without AMCL, and check the frames. The only things that affect the EKF's use of frames are the parameters you give it and tf_prefix, so if it's publishing transforms in the wrong namespace, it's one of those two things.

edit flag offensive delete link more

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

Question Tools



Asked: 2017-11-01 15:02:49 -0500

Seen: 358 times

Last updated: Jan 24 '18