ROS2_Foxy学习8——launch

  
The launch system in ROS 2 is responsible for helping the user describe the configuration of their system and then execute it as described. The configuration of the system includes what programs to run, where to run them, what arguments to pass them, and ROS specific conventions which make it easy to reuse components throughout the system by giving them each different configurations. It is also responsible for monitoring the state of the processes launched, and reporting and/or reacting to changes in the state of those processes.

launch文件的Python模板

项目	作用	项目	作用	项目	作用
package	功能包名（必须）	executable	可执行程序名（必须）	arguments	参数列表
output	输出类型 screen / log	namespace	名称空间	name	节点名
remappings	重映射	prefix	运行命令

1. 基础

   from launch import LaunchDescription
   from launch_ros.actions import Node
   
   def generate_launch_description():
       return LaunchDescription([
       	Node(
               package='my_package',
               executable='my_exe',
               name='my_node',
           	output='screen',
           	arguments=['39','-0.968','abc']    # 程序里面从 argv[1] 开始读取
           )
       ])
   

2. 延伸
   1. static_tf
   2. gdb调试
   3. 重映射

   from launch import LaunchDescription
   from launch_ros.actions import Node
   
   def generate_launch_description():
       return LaunchDescription([
       	# static tf
       	# 参数列表分别是 x,y,z,x,y,z,w,parent_frame,child_frame
           Node(
               package='tf2_ros',
               executable='static_transform_publisher',
               arguments = ['0.145', '0', '0', '0', '0', '1', '0', 'base_link', 'laser']
           ),
           # gdb调试
           Node(
               package='global_map',
               executable='global_map',
               prefix='xterm -e gdb -ex run --args'
           ),
           # 重映射
           Node(
               package='turtlesim',
               executable='mimic',
               remappings=[
                   ('/input/pose', '/turtlesim1/turtle1/pose'),
                   ('/output/cmd_vel', '/turtlesim2/turtle1/cmd_vel'),
               ]
           )
       ])
   

3. 运行

   ros2 launch your_path_to_launch/mylaunch.py
   

参考

ROS2 创建一个launch文件