【ROS的launch/urdf文件报错问题解决】Invalid roslaunch XML syntax: mismatched tag: line **, column**

【问题描述】：[ERROR] [1594263210.237284, 0.000000]: Invalid XML: mismatched tag: line 20, column 4

【原文件】第7、8行代码出错，arg标签打错了结束标签

<robot name="simple_box">
  <link name="my_box">
   <inertial>
     <origin xyz="2 0 0"/>
     <mass value="1.0"/>
     <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="100.0" iyz="0.0" izz="1.0"/>
   <inertial/>
   <visual>
     <origin xyz="2 0 1"/>
     <geometry>
       <box size="1 1 2"/>
     </geometry>
   </visual>
   <collision>
     <origin xyz="2 0 1"/>
     <geometry>
       <box size="1 1 2"/>
     </geometry>
   </collision>
  </link>
  <gazebo reference="my_box">
    <material>Gazebo/Blue</material>
  </gazebo>
</robot>

【修改文件】第7、8行代码出错，arg的结束标签放在前面即可。

<robot name="simple_box">
  <link name="my_box">
   <inertial>
     <origin xyz="2 0 0"/>
     <mass value="1.0"/>
     <inertia ixx="1.0" ixy="0.0" ixz="0.0" iyy="100.0" iyz="0.0" izz="1.0"/>
   </inertial>
   <visual>
     <origin xyz="2 0 1"/>
     <geometry>
       <box size="1 1 2"/>
     </geometry>
   </visual>
   <collision>
     <origin xyz="2 0 1"/>
     <geometry>
       <box size="1 1 2"/>
     </geometry>
   </collision>
  </link>
  <gazebo reference="my_box">
    <material>Gazebo/Blue</material>
  </gazebo>
</robot>