Cannot spawn Gurdy on Gazebo (quiz)

Course Support URDF for Robot Modeling
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1

I try to spawn the gurdy urdf model on Gazebo using the methods of the previous unit but the robot does not appear on Gazebo. This is the .launch file I use (spawn_gurdy.launch):

 <?xml version="1.0" encoding="UTF-8"?>
 
 <launch>
 
     <include file="$(find my_gurdy_description)/launch/spawn_urdf.launch">
 
         <arg name="x" value="0.0" />
 
        <arg name="y" value="0.0" />
 
         <arg name="z" value="0.5" />
 
         <arg name="urdf_robot_file" value="$(find my_gurdy_description)/urdf/gurdy_model.urdf" />
 
         <arg name="robot_name" value="gurdy" />
 
     </include>
 
 </launch>

and this is the spawn_urdf.launch file I include in the previous one:

     <?xml version="1.0" encoding="UTF-8"?>
 <launch>
 
     <arg name="x" default="0.0" />
     <arg name="y" default="0.0" />
     <arg name="z" default="0.0" />
 
     <arg name="urdf_robot_file" default="" />
     <arg name="robot_name" default="" />
 
     <param name="robot_description" command="cat $(arg urdf_robot_file)" />
 
     <node name="urdf_spawner" pkg="gazebo_ros" type="spawn_model" respawn="false" output="screen"
     args="-urdf -x $(arg x) -y $(arg y) -z $(arg z)  -model $(arg robot_name) -param robot_description"/>
 </launch>

The result I get on the terminal is this:

user:~$ roslaunch my_gurdy_description spawn_gurdy.launch
... logging to /home/user/.ros/log/86dbe4fe-d17e-11ea-a596-02977383c654/roslaunch-rosdscomputer-10276.log
Checking log directory for disk usage. This may take awhile.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

started roslaunch server http://rosdscomputer:32915/

SUMMARY
========

PARAMETERS
 * /robot_description: <?xml version="1....
 * /rosdistro: kinetic
 * /rosversion: 1.12.14

NODES
  /
    urdf_spawner (gazebo_ros/spawn_model)

ROS_MASTER_URI=http://master:11311

process[urdf_spawner-1]: started with pid [10329]
the rosdep view is empty: call 'sudo rosdep init' and 'rosdep update'
SpawnModel script started
[INFO] [1596015833.930685, 0.000000]: Loading model XML from ros parameter
[INFO] [1596015833.933228, 0.000000]: Waiting for service /gazebo/spawn_urdf_model
[INFO] [1596015833.934656, 0.000000]: Calling service /gazebo/spawn_urdf_model
[INFO] [1596015834.030421, 621.292000]: Spawn status: SpawnModel: Successfully spawned entity
[urdf_spawner-1] process has finished cleanly
log file: /home/user/.ros/log/86dbe4fe-d17e-11ea-a596-02977383c654/urdf_spawner-1*.log
all processes on machine have died, roslaunch will exit
shutting down processing monitor...
... shutting down processing monitor complete
done

I have not added the controllers yet as I do not know how to continue and I do not understand the error.

Thank you in advance for your help

2

There does not seem to be an error. You could try running a ‘roscore’ first in a different terminal and then executing your launch file. Also make sure that the robot description loaded correctly.

rosparam get /robot_description
3

Robot will not be visible in Gazebo if you do not define inertial tags in urdf file. Why that fact is not clearly communicated in the lectures?

Igor V