Ask Your Question
2

robot_pose_ekf and AMCL

asked 2017-10-29 21:56:44 -0500

Andrey gravatar image

Hi! I have my own robot that works on odometry and lidar using AMCL. Everything works perfectly. After that, I decided to use robot_pose_ekf to improve data. I use the MPU6050 sensor and odometry from wheels data for this. /robot_pose_ekf/odom_combined give me a data. But I encountered such a problem that I do not know how to connect the robot_pose_ekf package to my the ready system with the AMCL. I searched the Internet, and did not find the information. In which files do I need to make changes to connect robot_pose_ekf?

In launch file I wrote.

    <node pkg="robot_pose_ekf" type="robot_pose_ekf" name="robot_pose_ekf">
  <param name="output_frame" value="odom_combined"/>
  <param name="base_footprint_frame" value="base_link"/>
  <param name="freq" value="30.0"/>
  <param name="sensor_timeout" value="1.0"/>  
  <param name="odom_used" value="true"/>
  <param name="imu_used" value="true"/>
  <param name="vo_used" value="false"/>
  <param name="publish_tf" value="true"/>
  <remap from="odom" to="odom"/>
  <remap from="imu_data" to="imu_data" />
</node>

But navigation does not work. The terminal gets out of error.

Timed out waiting for transform from base_link to map to become available before running costmap, tf error: . canTransform returned after 0.100751 timeout was 0.1

Here is fragment of my original tf tree of working system, without robot_pose_ekf. Without robot_pose_ekf

With robot_pose_ekf graph is the same exept frame called not "odom" but "odom_combined" and published by robot_pose_ekf.

edit retag flag offensive close merge delete

1 Answer

Sort by ยป oldest newest most voted
1

answered 2017-10-30 06:30:00 -0500

Humpelstilzchen gravatar image

Your problem might be that you now have two parents for "base_link" in your tf tree, "odom" and "odom_combined".

robot_pose_ekf has two outputs, the published topic "odom_combined" and the tf transform:

  1. The tf transform looks misconfigured in your launch file, you have set output_frame to "odom_combined" which does not exist in your tf tree. Note: output_frame is not the name of the published odometry topic, but the name of your odometry frame, see rep 105. So you should set output_frame to "odom". Since you can have only one publisher for this transform, this implies that you disable your previous publisher of the odom->base_link transform which is "diff_tf" in your tf tree.

  2. Finally if you have any node that subscribes to /odom you might want it to subscribe to /robot_pose_ekf/odom_combined instead.

edit flag offensive delete link more

Comments

Thank a lot. I'' try it. Can you tell me if I need only to change the odom_frame_id parameter to connect to the amcl and that's all? And is there a problem in that, initially, the robot_pose_ekf transfer tf in base_footprint instead of base_linkl? I have remaped it in launch, but is will this work?

Andrey gravatar image Andrey  ( 2017-10-31 03:17:54 -0500 )edit
1
  1. You better not change the "odom_frame_id" param in amcl, just change it in robot_pose_ekf. 2. You have set "base_footprint_frame" param to "base_link", so I don't see any "base_footprint" frame.
Humpelstilzchen gravatar image Humpelstilzchen  ( 2017-10-31 04:31:11 -0500 )edit

Okay.How i can change "odom_frame_id" in robot_pose_ekf? I wrote param name="odom_frame_id" value="odom"/ in launching robot_pose_ekf but nothing happens. And if i did remap from="/robot_pose_ekf/odom_combined" to="odom" i have 2 topics with the same name with odom from diff_tf. How i can do this?

Andrey gravatar image Andrey  ( 2017-10-31 18:57:57 -0500 )edit
1

"odom_frame_id" is amcl parameter, corresponding parameter in robot_pose_ekf is "output_frame".

Humpelstilzchen gravatar image Humpelstilzchen  ( 2017-11-01 01:00:23 -0500 )edit

Okay, thank you I'll try it.

Andrey gravatar image Andrey  ( 2017-11-02 18:19:07 -0500 )edit

Your Answer

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

Add Answer

Question Tools

3 followers

Stats

Asked: 2017-10-29 21:56:44 -0500

Seen: 877 times

Last updated: Oct 30 '17