cannot roslaunch moveit_planning_execution.launch

edit

Hi all! I'm following the tutorial of industrial Create_a_MoveIt_Pkg_for_an_Industrial_Robot. When I stepped into the 2.Update Configuration Files and completed the moveit_planning_execution.launch, I tried roslaunch it,but it failed. Something was wrong like this:

redefining global property: pi
when processing file: /home/shantengfei/catkin_ws/src/jaka/urdf/jaka.urdf.xacro
while processing /home/shantengfei/catkin_ws/src/jaka_ur_moveit_config/launch/move_group.launch:
while processing /home/shantengfei/catkin_ws/src/jaka_ur_moveit_config/launch/trajectory_execution.launch.xml:
while processing /home/shantengfei/catkin_ws/src/jaka_ur_moveit_config/launch/jakaUr_moveit_controller_manager.launch.xml:
Invalid roslaunch XML syntax: not well-formed (invalid token): line 8, column 0
The traceback for the exception was written to the log file

. I defined the pi in xacro.So is this wrong? In addition, there is a tip "Invalid roslaunch XML syntax: not well-formed (invalid token): line 8, column 0 The traceback for the exception was written to the log file". Here is the launch file: <launch>

  <!-- Non-standard joint names:
       - Create a file jaka_ur_moveit_config/config/joint_names.yaml
       controller_joint_names: [joint_1, joint_2, ... joint_N] 
   - Update with joint names for your robot (in order expected by rbt controller)
   - and uncomment the following line: -->


 <!-- <rosparam command="load" file="$(find jaka_ur_moveit_config)/config/joint_names.yaml"/> -->

  <!-- the "sim" argument controls whether we connect to a Simulated or Real robot -->
  <!--  - if sim=false, a robot_ip argument is required -->
  <arg name="sim" default="true" />
  <arg name="robot_ip" unless="$(arg sim)" />


  <!-- load the robot_description parameter before launching ROS-I nodes -->
  <include file="$(find jaka_ur_moveit_config)/launch/planning_context.launch" >
    <arg name="load_robot_description" value="true" />
  </include>

  <!-- run the robot simulator and action interface nodes -->
  <group if="$(arg sim)">
    <include file="$(find industrial_robot_simulator)/launch/robot_interface_simulator.launch" />
  </group>

  <!-- run the "real robot" interface nodes -->
  <!--   - this typically includes: robot_state, motion_interface, and joint_trajectory_action nodes -->
  <!--   - replace these calls with appropriate robot-specific calls or launch files -->
  <group unless="$(arg sim)">
    <include file="$(find [robot_interface_pkg])/launch/robot_interface.launch" >
      <arg name="robot_ip" value="$(arg robot_ip)"/>
    </include>
  </group>



 <!-- publish the robot state (tf transforms) -->
  <node name="robot_state_publisher" pkg="robot_state_publisher" type="robot_state_publisher" />

  <include file="$(find jaka_ur_moveit_config)/launch/move_group.launch">
    <arg name="publish_monitored_planning_scene" value="true" />
  </include>

  <include file="$(find jaka_ur_moveit_config)/launch/moveit_rviz.launch">
    <arg name="config" value="true"/>
  </include>

  <include file="$(find jaka_ur_moveit_config)/launch/default_warehouse_db.launch" />

</launch>

So could anyone please tell me how to solve this problem?