이 글은 아래의 자료를 참고로 만들어졌습니다. docs.ros.org/en/dashing/Tutorials/Services/Understanding-ROS2-Services.html Understanding ROS 2 services — ROS 2 Documentation: Dashing documentation Goal: Learn about services in ROS 2 using command line tools. Nodes can communicate using services in ROS 2. Services only pass information to a node if that node specifically requests it, and will only do so once per requ..