RLException: Invalid ＜param＞ tag:

问题：RLException: Invalid tag: Cannot load command parameter [robot_description]: command [['/opt/ros/melodic/lib/xacro/xacro', '/home/rot/catkin_ws/src/rot_cararm/urdf/robot_base/base.urdf.xacro']] returned with code [2]. 

Param xml is
The traceback for the exception was written to the log file

原因：base.urdf.xacro文件有个路径给错

    rot_cararm)/urdf/robot_base/base.gazebo.xacro" />

因为是拷贝他人项目，路径文件名没有更改为自己设置的