【ROS】msg&srv

• ref: http://wiki.ros.org/ROS/Tutorials
  

• rospack = ros+pack(age) : provides information related to ROS packages
• roscd = ros+cd : changes directory to a ROS package or stack
• rosls = ros+ls : lists files in a ROS package
• roscp = ros+cp : copies files from/to a ROS package
• rosmsg = ros+msg : provides information related to ROS message definitions
• rossrv = ros+srv : provides information related to ROS service definitions
• catkin_make : makes (compiles) a ROS package
  • rosmake = ros+make : makes (compiles) a ROS package (if you’re not using a catkin workspace)
• catkin build: makes (compiles) a ROS package in an isolated manner while maintaining efficiency due to parallelisation
  • catkin_make + catkin_make_isolated

• 概览

  • msg: 简单的文本文件, 描述了ROS消息字段, 用于生成不同语言的消息源码
    • 位于包的msg目录

    Header header
    string child_frame_id
    geometry_msgs/PoseWithCovariance pose
    geometry_msgs/TwistWithCovariance twist
    

  • srv: 描述一个服务, 包括请求和回复
    • 位于包的srv目录
    • 类似msg文件, 含2部分: 请求和回复, —分隔

    int64 A
    int64 B
    ---
    int64 Sum
    

  msg

  • 创建msg

  roscd beginner_tutorials
  $ mkdir msg
  $ echo "int64 num" > msg/Num.msg
  

  补充
  package.xml

    <build_depend>message_generation</build_depend>
    <exec_depend>message_runtime</exec_depend>
  

  CMakeList.txt

  find_package(catkin REQUIRED COMPONENTS
     roscpp
     rospy
     std_msgs
     message_generation
  )
  catkin_package(
    ...
    CATKIN_DEPENDS message_runtime ...
    ...)
  add_message_files(
    FILES
    Num.msg
  )
  generate_messages(
    DEPENDENCIES
    std_msgs
  )
  

  rosmsg

  • rosmsg show [message type]
    • rosmsg show beginner_tutorials/Num
    • rosmsg show Num
    • list : List all messages
    • md5 : Display message md5num
    • package : List messages in a package
    • packages : List messages that contain messages

  srv

  • roscp [package_name] [file_to_copy_path] [copy_path] : 复制

  roscd beginner_tutorials
  mkdir srv
  roscp rospy_tutorials AddTwoInts.srv srv/AddTwoInts.srv
  

  补充
  package.xml

    <build_depend>message_generation</build_depend>
    <exec_depend>message_runtime</exec_depend>
  

  CMakeList.txt

  find_package(catkin REQUIRED COMPONENTS
     roscpp
     rospy
     std_msgs
     message_generation
  )
  add_service_files(
    FILES
    AddTwoInts.srv
  )
  

  rossrv

  • rossrv show [service type]
    • rossrv show beginner_tutorials/AddTwoInts

  catkin_make