Robotics StackExchange | Archived questions

Error when running markers.launch

OS : Ubuntu 14.04 LTS ROS : Indigo

I'm studying Stockroom_bot. (Book : Programming Robots with ROS, Ch.14) My source same the book's example.

I've just finished at gotobin.sh. So next step is 'markers.launch' There is an error when I run the markers.launch.

1. markers.launch - Error message is this:

[ WARN] [1533512740.109920017]: Command line arguments are deprecated. Consider using ROS parameters and remappings.
**[ INFO] [1533512740.112981476]: Subscribing to info topic
[ INFO] [1533512740.136521085]: AR tracker reconfigured: ENABLED 1.00 12.30 0.20 0.00
terminate called after throwing an instance of 'ros::InvalidNameException'
  what():  Character [0] is not valid as the first character in Graph Resource Name [0.8].  Valid characters are a-z, A-Z, / and in some cases ~.
           [ar_track_alvar-1] process has died [pid 13581, exit code -6, cmd /opt/ros/indigo/lib/ar_track_alvar/individualMarkersNoKinect 12.3 0.2   0.8 /head_camera/rgb/image_raw   /head_camera/rgb/camera_info /base_link __name:=ar_track_alvar __log:=/home/aaaabbbb/.ros/log/6bf17ba4-9909-11e8-ad84-645106a90f90/ar_track_alvar-1.log].
             log file: /home/aaaabbbb/.ros/log/6bf17ba4-9909-11e8-ad84-645106a90f90/ar_track_alvar-1*.log**

2. stockroom_bot.launch - error message is this

ERROR] [1533263314.110014050, 10.048000000]: Client [/artrackalvar] wants topic /headcamera/rgb/imageraw to have datatype/md5sum [sensormsgs/CameraInfo/c9a58c1b0b154e0e6da7578cb991d214], but our version has [sensormsgs/Image/060021388200f6f0f447d0fcd9c64743]. Dropping connection.

What is that means ? Why the ROS can't execute the markers.launch ? I don't know what I can do. And, ROS don't make the log file /home/...artrackalvar-1*.log

Please help me...

  1. This is my 'markers.launch' source

Asked by hyonietta on 2018-08-05 20:02:09 UTC

Comments

Can you post a copy of the 'markers.launch' file you're trying to use. There are actually two different errors described here, they seem to be something to do with missing/wrong topic names. But we'll need to see the launch file to be sure.

Asked by PeteBlackerThe3rd on 2018-08-06 05:27:57 UTC

I added my 'markers.launch' source. I'm using the book's stockroom_bot source. Should I edit stockroom_bot package sources? Or I run wrong method?

Asked by hyonietta on 2018-08-06 19:07:49 UTC

Answers

I ran into the same problem while running markers.launch. The key being the error message stating a type mismatch in the topics. I believe it has something to do with the order of arguments while initializing the ar_track_alvar node.

To fix it, change

  <node name="ar_track_alvar" pkg="ar_track_alvar"
        type="individualMarkersNoKinect" respawn="false" output="screen" 
        args="$(arg marker_size) $(arg max_new_marker_error) \
              $(arg max_track_error) $(arg cam_image_topic)  \
              $(arg cam_info_topic) $(arg output_frame)" />

to

  <node name="ar_track_alvar" pkg="ar_track_alvar"
        type="individualMarkersNoKinect" respawn="false" output="screen"> 
        <param name="marker_size"   type="double" value="$(arg marker_size)"/>
        <param name="max_new_marker_error"  type="double" value="$(arg max_new_marker_error)"/>
        <param name="max_track_error"   type="double" value="$(arg max_track_error)"/>
        <param name="output_frame"  type="string" value="$(arg output_frame)"/>

        <remap from="camera_image" to="$(arg cam_image_topic)"/>
        <remap from="camera_info" to="$(arg cam_info_topic)"/>
  </node>

Using parameter names and remap makes sure that the arguments are parsed correctly.

Asked by ajonna on 2018-09-06 10:04:07 UTC

Comments

Thank you! This problem would have sent me down the .launch file rabbit hole; at a time when I'm just trying to get a quick ROS overview.

Asked by cerebric on 2020-01-12 20:58:54 UTC