ROS2_Moveit2_Ur5e_Grasp项目详解（三）：ur5e_gripper_sim_control文件详解 📍 置顶

def generate_launch_description():
    """
    生成launch描述，定义launch文件的参数和入口点
    
    该函数声明所有launch参数并返回完整的LaunchDescription对象，
    包含参数声明和实际的launch设置函数。
    
    返回:
    LaunchDescription: 包含所有launch参数和设置函数的描述对象
    """
    declared_arguments = []
    ## 通用参数
    declared_arguments.append(
        DeclareLaunchArgument(
            "description_package",
            default_value="ur5e_gripper_moveit_config",
            description="包含机器人URDF/XACRO文件的描述包。通常不设置该参数，\
                         它允许使用自定义描述。",
        )
    )
    declared_arguments.append(
        DeclareLaunchArgument(
            "description_file",
            default_value="ur5e_gripper.urdf.xacro",
            description="包含机器人的URDF/XACRO描述文件。",
        )
    )
    declared_arguments.append(
        DeclareLaunchArgument(
            "prefix",
            default_value='""',
            description="关节名称前缀，对多机器人设置很有用。\
                         如果更改了此参数，则控制器配置中的关节名称也必须更新。",
        )
    )
    declared_arguments.append(
        DeclareLaunchArgument(
            "start_joint_controller",
            default_value="true",
            description="为机器人控制启用无头模式",
        )
    )
    declared_arguments.append(
        DeclareLaunchArgument(
            "initial_joint_controller",
            default_value="ur5e_arm_controller",
            description="要启动的机器人控制器。",
        )
    )
    declared_arguments.append(
        DeclareLaunchArgument("launch_rviz", default_value="False", description="是否启动RViz？")
    )

    print(f"\033[95mdeclared_arguments:{declared_arguments}\033[0m")
    return LaunchDescription(declared_arguments + [OpaqueFunction(function=launch_setup)])

def launch_setup(context, *args, **kwargs):
    """
    设置并启动UR5e机器人与夹爪的Gazebo仿真环境
    
    该函数配置机器人描述、控制器、可视化工具和Gazebo仿真环境，
    并按正确的依赖顺序启动所有必需的节点。
    
    参数:
    context: Launch上下文
    *args: 额外的位置参数
    **kwargs: 额外的关键字参数
    
    返回:
    list: 需要启动的节点列表
    """

    ## 通用参数
    description_package = LaunchConfiguration("description_package")
    description_file = LaunchConfiguration("description_file")
    launch_rviz = LaunchConfiguration("launch_rviz")
    gazebo_world_file = os.path.join(
        FindPackageShare(package='ur5e_gripper_moveit_config').find('ur5e_gripper_moveit_config'),
        'gazebo','sim_env.world'
    )
    
    ## 打印LaunchConfiguration的实际值
    print(f"\033[95mdescription_package: {description_package.perform(context)}\033[0m")
    print(f"\033[95mdescription_file: {description_file.perform(context)}\033[0m")
    print(f"\033[95mlaunch_rviz: {launch_rviz.perform(context)}\033[0m")
    print(f"\033[95mgazebo_world_file: {gazebo_world_file}\033[0m")


    ## RViz配置文件路径
    rviz_config_file = PathJoinSubstitution(
        [FindPackageShare(description_package), "rviz", "view_robot.rviz"]
    )

    ## 机器人描述内容（通过xacro处理URDF文件生成）
    robot_description_content = Command(
        [
            PathJoinSubstitution([FindExecutable(name="xacro")]),
            " ",
            PathJoinSubstitution(
                [FindPackageShare(description_package), "urdf", description_file]
            ),
        ]
    )
    robot_description = {"robot_description": robot_description_content}

    ## 机器人状态发布节点
    robot_state_publisher_node = Node(
        package="robot_state_publisher",
        executable="robot_state_publisher",
        output="both",
        parameters=[{"use_sim_time": True}, robot_description],
    )

    ## RViz可视化节点（根据launch_rviz参数决定是否启动）
    rviz_node = Node(
        package="rviz2",
        executable="rviz2",
        name="rviz2",
        output="log",
        arguments=["-d", rviz_config_file],
        condition=IfCondition(launch_rviz),
    )

    ## 关节状态广播器
    joint_state_broadcaster_spawner = Node(
        package="controller_manager",
        executable="spawner",
        arguments=["joint_state_broadcaster", "--controller-manager", "/controller_manager"],
    )

    ## 在关节状态广播器启动后再启动RViz
    delay_rviz_after_joint_state_broadcaster_spawner = RegisterEventHandler(
        event_handler=OnProcessExit(
            target_action=joint_state_broadcaster_spawner,
            on_exit=[rviz_node],
        )
    )

    ## UR5e机械臂控制器
    ur5e_arm_controller_spawner = Node(
        package="controller_manager",
        executable="spawner",
        arguments=["ur5e_arm_controller", "-c", "/controller_manager"],
    )

    ## Robotiq夹爪控制器
    robotiq_gripper_controller_spawner = Node(
        package="controller_manager",
        executable="spawner",
        arguments=["gripper_controller", "-c", "/controller_manager"],
    )

    ## Gazebo仿真环境
    gazebo = IncludeLaunchDescription(
        PythonLaunchDescriptionSource(
            [FindPackageShare("gazebo_ros"), "/launch", "/gazebo.launch.py"]
        ),
        launch_arguments={
            "world": gazebo_world_file,
        }.items(),
    )

    ## 在Gazebo中生成机器人实体
    gazebo_spawn_robot = Node(
        package="gazebo_ros",
        executable="spawn_entity.py",
        name="spawn_ur",
        arguments=["-entity", "ur5e_gripper", "-topic", "robot_description"],
        output="screen",
    )

    ## 需要启动的节点列表
    nodes_to_start = [
        robot_state_publisher_node,
        joint_state_broadcaster_spawner,
        delay_rviz_after_joint_state_broadcaster_spawner,
        ur5e_arm_controller_spawner,
        robotiq_gripper_controller_spawner,
        gazebo,
        gazebo_spawn_robot,
    ]

    return nodes_to_start