Hello, I am using this repository which controls a UR5 robot to pick an object from the conveyor belt. Now my goal is to launch two UR5 in the same simulation and control two UR5 at the same time for picking the object.

I have modified the launch file such that I can launch two UR5 in the same simulation but the python file which used to control the moveit for controlling the robot movement fails. The launch file is here,

<?xml version="1.0"?>
<launch>
  <param name="red_box_path" type="str" value="$(find ur5_notebook)/urdf/red_box.urdf"/>
  <param name="/use_sim_time" value="true" />
  <arg name="robot_name"/>
  <arg name="init_pose"/>

  <arg name="limited" default="true"/>
  <arg name="paused" default="false"/>
  <arg name="gui" default="true"/>
  <arg name="debug" default="false" />
  <arg name="sim" default="true" />
  <arg name="transmission_hw_interface" default="hardware_interface/PositionJointInterface" />


  <!-- startup simulated world -->
  <include file="$(find gazebo_ros)/launch/empty_world.launch">
    <arg name="world_name" default="worlds/empty.world"/>
    <arg name="paused" value="$(arg paused)"/>
    <arg name="gui" value="$(arg gui)"/>
  </include>

  <!-- spawn the conveyor_belt in gazebo -->
  <node name="spawn_conveyor_belt" pkg="gazebo_ros" type="spawn_model" args="-file $(find ur5_notebook)/urdf/conveyor_belt.urdf -urdf -model conveyor_belt" />
  <!-- spawn the conveyor_belt in gazebo -->
  <node name="bin" pkg="gazebo_ros" type="spawn_model" args="-file $(find ur5_notebook)/urdf/bin.urdf -urdf -model bin -y 0.8 -x -0.5 -z 0.05" />
  <!-- the red blocks spawner node -->
  <node name="blocks_spawner" pkg="ur5_notebook" type="blocks_spawner" output="screen" />

  <!-- the cylinder poses publisher node -->
  <node name="blocks_poses_publisher" pkg="ur5_notebook" type="blocks_poses_publisher" output="screen" />

  <!-- spwan ur5 -->
  <!-- send robot urdf to param server -->


  <group ns="robot1">
    <param name="tf_prefix" value="robot1_tf" />
        <include file="$(find ur_gazebo)/launch/ur5.launch">
                <arg name="init_pose" value="-z 0.2 -y 0.7"/>
                <arg name="robot_name" value="robot1"/>
        </include>


        <include file="$(find ur5_moveit_config)/launch/move_group.launch">
          <arg name="limited" default="$(arg limited)"/>
          <arg name="debug" default="$(arg debug)" />
        </include>


        <node name="ur5_vision" pkg="ur5_notebook" type="ur5_vision.py" output="screen" />
        <node name="ur5_mp" pkg="ur5_notebook" type="ur5_mp.py" output="screen" />

        <node name="ur5_gripper" pkg="ur5_notebook" type="ur5_gripper.py" output="screen"/>




        <remap if="$(arg sim)" from="follow_joint_trajectory" to="robot1/arm_controller/follow_joint_trajectory"/>

        <!-- Remap follow_joint_trajectory -->

        <!-- Launch moveit -->

          <!-- the cylinder poses publisher node -->

  </group>

  <group ns="robot2">

      <param name="tf_prefix" value="robot2_tf" />
        <include file="$(find ur_gazebo)/launch/ur5.launch">
                <arg name="init_pose" value="-z 0.2 -y -0.9"/>
                <arg name="robot_name" value="robot2"/>
        </include>


        <include file="$(find ur5_moveit_config)/launch/move_group.launch">
          <arg name="limited" default="$(arg limited)"/>
          <arg name="debug" default="$(arg debug)" />
        </include>


        <node name="ur5_vision" pkg="ur5_notebook" type="ur5_vision.py" output="screen" />
        <node name="ur5_mp" pkg="ur5_notebook" type="ur5_mp.py" output="screen" />

        <node name="ur5_gripper" pkg="ur5_notebook" type="ur5_gripper.py" output="screen"/>




        <remap if="$(arg sim)" from="follow_joint_trajectory" to="robot2/arm_controller/follow_joint_trajectory"/>

        <!-- Remap follow_joint_trajectory -->

        <!-- Launch moveit -->

          <!-- the cylinder poses publisher node -->

  </group>


  <!-- for ros control to be used with scara robot -->
  <!--   <param name="/scara_robot_left/robot_description" textfile="$(find two_scara_collaboration)/urdf/scara_robot_left.urdf" />-->

<!-- spawn the red_box in gazebo -->
<!-- node name="spawn_red_box" pkg="gazebo_ros" type="spawn_model" args="-file $(find ur5_notebook)/urdf/red_box.urdf -urdf -model red_box"/ -->


</launch>

which launches two robots successfully, but they don't perform any actions If you notice the launch files there are three python files, which are important in performing the task on robot

1) ur_vision.py # recognizes the the object on the conveyor belt which is to be grasped

2) ur_mp.py # this is the motion planning file which moves the robot to the object to grasp it

3) ur_gripper.py # this is the file which tells the robot to with just one robot it works perfectly fine but when I launch the above launch file things get more complex with the namespaces

I get the following error when I execute this launch file

Traceback (most recent call last):
  File "/home/murtaza/catkin_ws/src/ur5_notebook/ur5_mp.py", line 385, in <module>
    mp=ur5_mp()
  File "/home/murtaza/catkin_ws/src/ur5_notebook/ur5_mp.py", line 67, in __init__
    self.arm = moveit_commander.MoveGroupCommander(group_name)
  File "/opt/ros/melodic/lib/python2.7/dist-packages/moveit_commander/move_group.py", line 52, in __init__
    self._g = _moveit_move_group_interface.MoveGroupInterface(name, robot_description, ns)
RuntimeError: Unable to connect to move_group action server 'move_group' within allotted time (5s)
[INFO] [1568731976.642265, 4.885000]: Stopping the robot
Traceback (most recent call last):
  File "/opt/ros/melodic/lib/python2.7/dist-packages/rospy/core.py", line 572, in signal_shutdown
    h()
  File "/home/murtaza/catkin_ws/src/ur5_notebook/ur5_mp.py", line 168, in cleanup
    self.arm.stop()
AttributeError: 'ur5_mp' object has no attribute 'arm'

My question is if these three python files should be included within the respective namespaces separately (i.e. within group ns = "robot1" and group ns = "robot2") or is there any changes I need to do in the python files itself to make sure that the move it recognizes the namespaces of the respective robots defined in the launch file

Most importantly, the moveit python interface fails while executing the ur5_mp.py file giving the above error because this file contains all the motion planning codes to move the robot using moveit interface.

Please help me in solving this problem