[feat]:完成9.3章节内容

docs/chapt9/9.3为FishBot配置两轮差速控制插件.md

@@ -408,15 +408,77 @@ rviz2
 
 ### 4.6 在RVIZ2中显示机器人模型
 
+虽然机器人的轨迹已经在RVIZ中显示出来了，但是并没有机器人的模型，也看不到轮子的转动，小鱼来带你一起解决这个问题。
 
+前面小鱼介绍过，要发布机器人模型我们所使用的节点是`robot_state_publisher`,所以我们在`gazebo.launch.py`中加入这个节点，同时再加上rviz2的启动节点，最终的`gazebo.launch.py`内容如下：
 
+```python
 
+import os
+from launch import LaunchDescription
+from launch.actions import ExecuteProcess
+from launch_ros.actions import Node
+from launch_ros.substitutions import FindPackageShare
 
 
+def generate_launch_description():
+    robot_name_in_model = 'fishbot'
+    package_name = 'fishbot_description'
+    urdf_name = "fishbot_gazebo.urdf"
 
+    ld = LaunchDescription()
+    pkg_share = FindPackageShare(package=package_name).find(package_name) 
+    urdf_model_path = os.path.join(pkg_share, f'urdf/{urdf_name}')
 
+    # Start Gazebo server
+    start_gazebo_cmd = ExecuteProcess(
+        cmd=['gazebo', '--verbose', '-s', 'libgazebo_ros_factory.so'],
+        output='screen')
 
+    # Launch the robot
+    spawn_entity_cmd = Node(
+        package='gazebo_ros', 
+        executable='spawn_entity.py',
+        arguments=['-entity', robot_name_in_model,  '-file', urdf_model_path ], output='screen')
+	
+    # Start Robot State publisher
+    start_robot_state_publisher_cmd = Node(
+        package='robot_state_publisher',
+        executable='robot_state_publisher',
+        arguments=[urdf_model_path]
+    )
 
+    # Launch RViz
+    start_rviz_cmd = Node(
+        package='rviz2',
+        executable='rviz2',
+        name='rviz2',
+        output='screen',
+        # arguments=['-d', default_rviz_config_path]
+        )
+
+    ld.add_action(start_gazebo_cmd)
+    ld.add_action(spawn_entity_cmd)
+    ld.add_action(start_robot_state_publisher_cmd)
+    ld.add_action(start_rviz_cmd)
+
+
+    return ld
+```
+
+保存编译启动
+
+```shell
+colcon build
+```
+
+```shell
+ros2 launch fishbot_description gazebo.launch.py
+```
+
+然后继续启动键盘控制，Enjoy It!
+
+![boot](9.3%E4%B8%BAFishBot%E9%85%8D%E7%BD%AE%E4%B8%A4%E8%BD%AE%E5%B7%AE%E9%80%9F%E6%8E%A7%E5%88%B6%E6%8F%92%E4%BB%B6/imgs/boot.gif)