添加 创建和显示机器人所用的launch文件

创建和显示机器人所用的launch文件

@@ -0,0 +1,41 @@
+import launch
+import launch_ros
+from ament_index_python.packages import get_package_share_directory
+import os 
+def generate_launch_description():
+    #获取urdf路径
+    urdf_package_path = get_package_share_directory("fishbot_description")
+    default_rviz_config_path = os.path.join(urdf_package_path,"config","display_robot_model.rviz")
+    default_urdf_path = os.path.join(urdf_package_path,"urdf","first_robot.urdf")
+    #声明一个urdf目录的参数，方便修改
+    action_declare_arg_mode_path = launch.actions.DeclareLaunchArgument(
+        name="model",default_value=str(default_urdf_path),description="加载模型文件路径"
+    )
+    #通过文件路径，获取内容，并转化成数值对象，以供传入 robot_state_publisher
+    substitutions_command_result = launch.substitutions.Command(["xacro ",launch.substitutions.LaunchConfiguration("model")])
+    
+    robot_description_value = launch_ros.parameter_descriptions.ParameterValue(substitutions_command_result,value_type=str)
+
+    action_robot_state_publisher = launch_ros.actions.Node(
+        package="robot_state_publisher",
+        executable="robot_state_publisher",
+        parameters=[{f"robot_description":robot_description_value}]
+    )
+    
+    action_joint_state_publisher = launch_ros.actions.Node(
+        package="joint_state_publisher",
+        executable="joint_state_publisher"
+    )
+
+    action_rviz_node = launch_ros.actions.Node(
+        package="rviz2",
+        executable="rviz2",
+        arguments=["-d",default_rviz_config_path]
+    )
+    
+    return launch.LaunchDescription([
+        action_declare_arg_mode_path,
+        action_robot_state_publisher,
+        action_joint_state_publisher,
+        action_rviz_node,
+    ])