Turtlesim Tutorial: ERROR Communication with [/my_turtle] raised an error(groovy) [closed]

asked 2013-01-04 13:15:35 -0500

this post is marked as community wiki

This post is a wiki. Anyone with karma >75 is welcome to improve it.

I'm running groovy on ubuntu 12.04.1. I'm new to ROS. When I was going through the tutorials on

w ww.ros.org/wiki/ROS/Tutorials/UnderstandingNodesTutorials/UnderstandingNodes

roscore worked as the tutorials describes. When I typed

$ rosrun turtlesim turtlesim_node __name:=my_turtle

two turtles showed up. I ran

$ rosnode list

and I got the following information:


As noted in the tutorials, I shouldn't get the /turtlesim in the list. So I set the environment variables according to the page single machine configuration, I set

$ export ROS_HOSTNAME=localhost
$ export ROS_MASTER_URI=htt p://localhost:11311

and sourced the variables. The last few lines of my ~/.bashrc file are:

export ROS_HOSTNAME=localhost
export ROS_MASTER_URI=htt p://localhost:11311
source /opt/ros/groovy/setup.bash

I added a space in the URI, cos I'm not allowed to post link yet. I ran the codes again, but /turtlesim was still in the list. I ran roswtf after, and I got the following information:

No package or stack in context
Static checks summary:

No errors or warnings
Beginning tests of your ROS graph. These may take awhile...
analyzing graph...
... done analyzing graph
running graph rules...
... done running graph rules

Online checks summary:

Found 1 warning(s).
Warnings are things that may be just fine, but are sometimes at fault

WARNING The following node subscriptions are unconnected:
* /turtlesim:
* /turtle1/command_velocity
* /my_turtle:
* /turtle1/command_velocity

Found 1 error(s).

ERROR Communication with [/my_turtle] raised an error:

I searched here and didn't find similar questions, so what can I do to fix this problem? Thanks in advance.

edit retag flag offensive reopen merge delete

Closed for the following reason duplicate question by Boris
close date 2013-01-05 19:12:09


Have you tried to kill all running nodes and restart the roscore? Also it might be essential to reopen all terminals you are using for nodes.

Boris gravatar imageBoris ( 2013-01-04 17:49:31 -0500 )edit

I killed the node /my_turtle and used $ rosrun turtlesim turtlesim_node __name:=other_name, unless I restarted the roscore, /my_turtle will still be in the list.

aldaris gravatar imagealdaris ( 2013-01-05 18:37:13 -0500 )edit

This is actually a duplicate question of this one. It looks like a bug in turtlesim_node as it doesn't close properly on receiving SIGINT.

Boris gravatar imageBoris ( 2013-01-05 19:09:13 -0500 )edit