[model-4] process has died [pid 29477, exit code 1, cmd /opt/ros/melodic/lib/gazebo_ros/spawn_model -urdf -model mycar -param robot_description

[model-4] process has died [pid 31928, exit code 1, cmd /opt/ros/melodic/lib/gazebo_ros/spawn_model -urdf -model mycar -param robot_description __name:=model __log:=/home/mjm/.ros/log/e4b04588-8cd5-11ed-8ee9-00e04c6816f4/model-4.log].
log file: /home/mjm/.ros/log/e4b04588-8cd5-11ed-8ee9-00e04c6816f4/model-4*.log

执行xacro命令查看所有的中文字符，并逐一删除；

<?xml version="1.0" encoding="utf-8"?>
<!-- =================================================================================== -->
<!-- |    This document was autogenerated by xacro from build_car_gazebo.xacro         | -->
<!-- |    EDITING THIS FILE BY HAND IS NOT RECOMMENDED                                 | -->
<!-- =================================================================================== -->
<!-- 组合小车底盘与摄像头 -->
<robot name="my_car_camera">
  <!-- 宏:黑色设置 -->
  <material name="black">
    <color rgba="0.0 0.0 0.0 1.0"/>
  </material>
  <!-- 质量  -->
  <!-- 底盘 -->
  <link name="base_footprint">
    <visual>
      <geometry>

去掉所有

<?xml version="1.0" encoding="utf-8"?>
<!-- =================================================================================== -->
<!-- |    This document was autogenerated by xacro from build_car_gazebo.xacro         | -->
<!-- |    EDITING THIS FILE BY HAND IS NOT RECOMMENDED                                 | -->
<!-- =================================================================================== -->
<robot name="my_car_camera">
  <material name="black">
    <color rgba="0.0 0.0 0.0 1.0"/>
  </material>
  <link name="base_footprint">
    <visual>
      <geometry>
        <sphere radius="0.001"/>
      </geometry>
    </visual>
  </link>
  <link name="base_link">
    <visual>
      <geometry>
        <cylinder length="0.08" radius="0.1"/>
      </geometry>
      <origin rpy="0 0 0" xyz="0 0 0"/>
      <material name="yellow">
        <color rgba="0.5 0.3 0.0 0.5"/>
      </material>
    </visual>
    <collision>
      <geometry>
        <cylinder length="0.08"