feat: 更新第九章

chapt9/fishbot_ws/src/ydlidar_ros2/launch/ydlidar.py

@@ -0,0 +1,29 @@
+from launch.exit_handler import ignore_exit_handler, restart_exit_handler
+from ros2run.api import get_executable_path
+
+
+def launch(launch_descriptor, argv):
+    ld = launch_descriptor
+    package = 'ydlidar'
+    ld.add_process(
+        cmd=[get_executable_path(package_name=package, executable_name='ydlidar_node')],
+        name='ydlidar_node',
+        exit_handler=restart_exit_handler,
+    )
+    package = 'tf2_ros'
+    ld.add_process(
+        # The XYZ/Quat numbers for base_link -> laser_frame are taken from the
+        # turtlebot URDF in
+        # https://github.com/turtlebot/turtlebot/blob/931d045/turtlebot_description/urdf/sensors/astra.urdf.xacro
+        cmd=[
+            get_executable_path(
+                package_name=package, executable_name='static_transform_publisher'),
+            '0', '0', '0.02',
+            '0', '0', '0', '1',
+            'base_link',
+            'laser_frame'
+        ],
+        name='static_tf_pub_laser',
+        exit_handler=restart_exit_handler,
+    )
+    return ld