Search code examples
ros

redefining global symbol: pi error while ceating a launch file

created a launch file where my robot should open on the gazebo world and when in try to run the launch file using roslaunch i get the following error

redefining global symbol: pi
when processing file: /home/akash/project/src/techman_robot_ros-master/tm_grasp_description/urdf/tm700.urdf.xacro
included from: /home/akash/project/src/techman_robot_ros-master/tm_grasp_description/urdf/tm700_robot.urdf.xacro
xacro.py is deprecated; please use xacro instead
started roslaunch server http://akash:37109/

still i can see my gazebo world but cannot see the robot imported.

and this was the launch file

<launch>
  <arg name="eih" default="false" />
  <arg name="limited" default="false"/>

  <group unless="$(arg eih)">
    <param unless="$(arg limited)" name="robot_description" command="$(find xacro)/xacro.py '$(find tm_grasp_description)/urdf/tm700_robot.urdf.xacro'" />
        <param if="$(arg limited)" name="robot_description" command="$(find xacro)/xacro.py '$(find tm_grasp_description)/urdf/tm700_robot_joint_limited.urdf.xacro'" />
      </group>
      <group if="$(arg eih)">
    <param unless="$(arg limited)" name="robot_description" command="$(find xacro)/xacro.py '$(find tm_grasp_description)/urdf/tm700_robot_eih.urdf.xacro'" />
    <param if="$(arg limited)" name="robot_description" command="$(find xacro)/xacro.py '$(find tm_grasp_description)/urdf/tm700_robot_joint_limited_eih.urdf.xacro'" />
  </group>
<include file="$(find gazebo_ros)/launch/empty_world.launch">
        <arg name="paused" value="false"/>
        <arg name="use_sim_time" value="true"/>
    <arg name="gui" value="true"/>
    <arg name="headless" value="false"/>
    <arg name="debug" value="false"/>
            <arg name="world_name" 
                 value="$(find tm700_moveit_config)/launch/gg.world"/>


</include>

</launch>
Solution

  • Since ROS Jade Xacro internally uses functions and constants from Python math module such as pi when converting a Xacro to a URDF robot description. It seems like tm700.urdf.xacro (and several other Xacro-files in the package) for some reason has pi defined in line 8

    <property name="pi" value="3.14159265" />

    which is in conflict with the existing definition from the math module. Therefore the generation of your robot description fails. Delete all the definitions of pi from the Xacro-files, then it should work.