(ros2)rviz2中显示机器人模型最小系统

<launch>
    <group>
        <let name="robot_description" value="$(command 'xacro $(find-pkg-share gazebo_pkg)/urdf/total.xacro')"/>
        <node pkg="robot_state_publisher" exec="robot_state_publisher">
            <param name="robot_description" value="$(var robot_description)"/>
        </node>
        <node name="joint_state_publisher" exec="joint_state_publisher" pkg="joint_state_publisher"/>
        <node pkg="rviz2" exec="rviz2"/>
    </group>
</launch>

?3个包一个都不能少

可以看到rviz订阅了/robot_description? ? ? ? 所以我们才需要param参数robot_description

来看看是谁发布的/robot_description????????

?/joint_state_publisher订阅了/robot_state_publisher

?/robot_state_publisher是发布了/robot_description,另外2个节点（rviz2和joint_state_publisher)订阅了这个节点

为什么没有/joint_state_publisher会无法正常显示轮子呢？

应该就是/joint_state_publisher还发布了/parameter_events，二rviz2订阅了这个吧。