ros launch file

<launch>
<node pkg="gazebo" type="gazebo" name="gazebo" args="$(find gazebo_worlds)/worlds/empty.world"></node>

<!-- send world urdf to param server -->
<param name="world/robot_description" command="$(find xacro)/xacro.py $(find cob_gazebo_worlds)/common/worlds/ipa-kitchen.urdf.xacro" />

<!-- push world_description to factory and spawn world model in gazebo -->
<node ns="world" name="spawn_urdf_world" pkg="gazebo" type="spawn_model" args="-urdf -param robot_description -namespace world -x 0 -y 0 -z 0.01 -R 0.0 -P 0.0 -Y 0 -model ipa-kitchen" respawn="false" output="screen" />

<node ns="world" name="joint_state_publisher" pkg="joint_state_publisher" type="joint_state_publisher">
  <param name="publish_frequency" type="double" value="1.0" />
  <param name="tf_prefix" type="string" value="world_tf" />
 </node>
 <node ns="world" pkg="robot_state_publisher" type="state_publisher" name="robot_state_publisher">
  <param name="publish_frequency" type="double" value="1.0" />
  <param name="tf_prefix" type="string" value="world_tf" />
 </node>

<param name="/use_sim_time" value="true"/>

<node name="rviz" pkg="rviz" type="rviz"/>

</launch>