ROS_Gazebo_multipleRobotsLaunch_2

<launch>
 <group ns = "crowd2">
  <param name="robot_description" command="$(find xacro)/xacro.py '$(find turtlebot_description)/urdf/turtlebot.urdf.xacro'" />

  <node name="spawn_turtlebot_model" pkg="gazebo" type="spawn_model" args="$(optenv ROBOT_INITIAL_POSE) -unpause -urdf -param robot_description -model turtlebot-2 -x -2" respawn="false" output="screen" />

  <node pkg="diagnostic_aggregator" type="aggregator_node" name="diagnostic_aggregator" >
    <rosparam command="load" file="$(find turtlebot_bringup)/config/diagnostics.yaml" />
  </node>
 </group>
</launch>