ros2.md

Ros2

1. ROS Concepts and Design Patterns

https://osrf.github.io/ros2multirobotbook/ros2_design_patterns.html

• Topics and Types
  • nodes publish and subscribe via topics, each of which has a name and a type
• Services
  • form of remote procedure call(RPC)
  • service is implemented using a pair of ROS messages(request & reply)
  • infrequent, on-demand interactions among nodes, ROS services are a good choice.
• Actions
  • for goal-oriented, time-extended tasks.(compare with service)
  • action is defined by 3 ROS messages(goal, result, feedback)
  • on-demand, long-running behaviors, ROS actions are a good choice.
• Parameters
• Callbacks

2. Nodes

• Subprograms in your application, responsible for only one thing.
• Combined into a graph
• Communicate with each other through topics, services, and parameters.
• Fault tolerance.
• 패키지 안에 존재

3. Topics

• A Topic is a named bus over which nodes exchange messages
• Undirectional data stream (pub/sub)
• Anonymous
  • pub/sub은 topic과만 통신하며, 데이터가 어디로 부터 오고 가는지 식별하지 않음
• A topic has a message type