feat(level1): ROS2 完全体 12 包 / 80 测试 / 23 文档 / 工程化 / Docker 分组

src/cpp_robot_tf2/launch/robot_tf2_launch.py

@@ -1,72 +1,60 @@
+"""robot_tf2_launch.py - 启动 URDF + JointStatePublisher + robot_state_publisher + Tf2Listener。
+
+设计思想:
+    - 用 xacro 解析 URDF(ROS2 工业标准,简单 URDF 可直接读)
+    - robot_state_publisher 订阅 /joint_states + URDF → 动态 TF → /tf
+    - Tf2Listener 查 gripper 在 base_link 下位姿
+    - 跨包: urdf 来自 cpp_robot_tf2, robot_state_publisher 来自 ros-humble-robot-state-publisher
 """
-robot_tf2_launch.py —— 启动 3 关节机械臂的 TF2 演示。
-
-启动顺序:
-    joint_state_publisher (本包) → /joint_states
-                                ↓
-    robot_state_publisher  (系统包 ros-humble-robot-state-publisher)
-       读取 URDF + JointState → 算 base_link -> link1 -> link2 -> gripper 的 TF → /tf
-                                ↓
-    tf2_listener (本包) 查 base_link -> gripper,周期打印末端位姿。
-
-URDF 通过 CommandLineAction 用 xacro/直接读 XML,
-这里用 'command' 直接 cat 文件,launch 时读出来给 robot_state_publisher。
-"""
-
-import os
-
 from launch import LaunchDescription
-from launch.actions import DeclareLaunchArgument
-from launch.substitutions import LaunchConfiguration
+from launch.substitutions import Command, FindExecutable, PathJoinSubstitution
 from launch_ros.actions import Node
-
-from ament_index_python.packages import get_package_share_directory
+from launch_ros.substitutions import FindPackageShare
 
 
-def generate_launch_description():
-    pkg_share = get_package_share_directory('cpp_robot_tf2')
-    urdf_path = os.path.join(pkg_share, 'urdf', 'simple_arm.urdf')
+def generate_launch_description() -> LaunchDescription:
+    """生成启动描述:URDF + JointState + robot_state_publisher + TF listener。
 
-    # robot_description 参数:把 URDF 文件内容作为字符串直接传入。
-    # 注意:不在 launch 时执行 shell 命令(launch 的 Command 列表拼接有时会
-    #       丢空格,产生 'cat/root/...' 之类错误);改为 launch 启动前直接读文件。
-    with open(urdf_path, 'r', encoding='utf-8') as f:
-        robot_description = f.read()
+    Returns:
+        LaunchDescription: 启动描述实例。
+    """
+    # URDF 路径(用包内 urdf/ 目录,跨平台安全)
+    urdf_path = PathJoinSubstitution([
+        FindPackageShare('cpp_robot_tf2'),
+        'urdf',
+        'simple_arm.urdf',
+    ])
 
-    use_sim_time = LaunchConfiguration('use_sim_time')
+    # 用 cat 读 URDF 内容(给 robot_state_publisher 用)
+    robot_description = Command([
+        FindExecutable(name='cat'),
+        ' ',
+        urdf_path,
+    ])
 
     return LaunchDescription([
-        DeclareLaunchArgument(
-            'use_sim_time', default_value='false',
-            description='Use simulation (Gazebo) clock if true'),
-
-        # 1) JointState 发布者:本包 C++ 节点,模拟关节运动。
+        # 1) JointStatePublisher(C++ 发布关节角度)
         Node(
             package='cpp_robot_tf2',
-            executable='joint_state_publisher',
-            name='joint_state_publisher_cpp',
+            executable='joint_state_publisher_cpp',
+            name='joint_state_publisher',
             output='screen',
-            parameters=[{'use_sim_time': use_sim_time}],
         ),
 
-        # 2) robot_state_publisher:ROS2 系统包,URDF + JointState -> /tf。
+        # 2) robot_state_publisher(ROS2 系统包) — URDF + /joint_states → /tf
         Node(
             package='robot_state_publisher',
             executable='robot_state_publisher',
             name='robot_state_publisher',
             output='screen',
-            parameters=[{
-                'robot_description': robot_description,
-                'use_sim_time': use_sim_time,
-            }],
+            parameters=[{'robot_description': robot_description}],
         ),
 
-        # 3) tf2_listener:本包 C++ 节点,周期打印 gripper 位姿。
+        # 3) TF2 listener(C++ 查 gripper 位姿)
         Node(
             package='cpp_robot_tf2',
-            executable='tf2_listener',
-            name='tf2_listener_cpp',
+            executable='tf2_listener_cpp',
+            name='tf2_listener',
             output='screen',
-            parameters=[{'use_sim_time': use_sim_time}],
         ),
     ])