运行ros2 launch nav2_bringup tb3_simulation_launch.py时打不开gazebo

为此苦恼了很久，甚至觉得是环境问题…问了同伴之后得以解决，官方给的模型文件有问题
将/opt/ros/galactic/share/nav-bringup/worlds/waffle.world改成下面的内容就好了。希望能帮到为此困扰的人。

<?xml version="1.0"?>
<sdf version="1.6">
  <world name="default">

    <include>
      <uri>model://ground_plane</uri>
    </include>

    <include>
      <uri>model://sun</uri>
    </include>

    <scene>
      <shadows>false</shadows>
    </scene>

    <gui fullscreen='0'>
      <camera name='user_camera'>
        <pose frame=''>0.319654 -0.235002 9.29441 0 1.5138 0.009599</pose>
        <view_controller>orbit</view_controller>
        <projection_type>perspective</projection_type>
      </camera>
    </gui>

    <physics type="ode">
      <real_time_update_rate>1000.0</real_time_update_rate>
      <max_step_size>0.001</max_step_size>
      <real_time_factor>1</real_time_factor>
      <ode>
        <solver>
          <type>quick</type>
          <iters>150</iters>
          <precon_iters>0</precon_iters>
          <sor>1.400000</sor>
          <use_dynamic_moi_rescaling>1</use_dynamic_moi_rescaling>
        </solver>
        <constraints>
          <cfm>0.00001</cfm>
          <erp>0.2</erp>
          <contact_max_correcting_vel>2000.000000</contact_max_correcting_vel>
          <contact_surface_layer>0.01000</contact_surface_layer>
        </constraints>
      </ode>
    </physics>

    <model name="turtlebot3_world">
      <static>1</static>
      <include>
        <uri>model://turtlebot3_world</uri>
      </include>
    </model>

    <model name="turtlebot3_waffle"> 
      <pose>-2.0 -0.5 0.01 0.0 0.0 0.0</pose>

      <link name="base_footprint"/>

      <link name="base_link">

        <inertial>
          <pose>-0.064 0 0.048 0 0 0</pose>
          <inertia>
            <ixx>0.001</ixx>
            <ixy>0.000</ixy>
            <ixz>0.000</ixz>
            <iyy>0.001</iyy>
            <iyz>0.000</iyz>
            <izz>0.001</izz>
          </inertia>
          <mass>1.0</mass>
        </inertial>

        <collision name="base_collision">
          <pose>-0.064 0 0.048 0 0 0</pose>
          <geometry>
            <box>
              <size>0.265 0.265 0.089</size>
            </box>
          </geometry>
        </collision>

      </link>

      <link name="imu_link">
        <sensor name="tb3_imu" type="imu">
          <always_on>true</always_on>
          <update_rate>200</update_rate>
          <imu>
            <angular_velocity>
              <x>
                <noise type="gaussian">
                  <mean>0.0</mean>
                  <stddev>2e-4</stddev>
                </noise>
              </x>
              <y>
                <noise type="gaussian">
                  <mean>0.0</mean>
                  <stddev>2e-4</stddev>
                </noise>
              </y>
              <z>
                <noise type="gaussian">
                  <mean>0.0</mean>
                  <stddev>2e-4</stddev>
                </noise>
              </z>
            </angular_velocity>
            <linear_acceleration>
              <x>
                <noise type