ROS foundation - the basic concepts and simple tools (1)

1. What is ROS?

Robot operating System, simply robot operating system, the framework of weak coupling distributed processes, message passing between processes and management. Hardware abstraction and device control.

2, the node (node)

• ROS node is the core entity.
• ROS program period
• ROS communicate using middleware
• Can independently start and stop between nodes

3, and related concepts node

• message
• topic
• roscore :

1. There is one and only one can run roscore
2. You must first start roscore
3. Responsible for scheduling communications
4. Roscore publisher nodes and communications (e.g., to initialize a topic)

• publisher、subscriber

4, tool

　　catkin_create_pkg: Creating a package

　　catkin_make: Compile ROS program

　　rosrun: Run the program ros

　　rostopic: topics related to command

　　　　　　rostopic list; rostopic Hz topic1; rostopic topic1 bw; rostopic info topic1; rostopic echo topic1

　　rosnode list: to see a list of nodes running production

　　roslaunch: .launch by editing the file automatically start multiple nodes

　　rosbag: record and playback data on the topic

　　　　　　rosbag record topic1

　　　　　　rosbag play   name1.bag

         rqt_plot: for visualization of the results

5, common tools Details

catkin_create_pkg:

　　catkin_create_pkg   [packageNmae] [dependency]

　　

 

　　Dependencies: roscpp: using c ++ compiler, c ++ compatible interfaces; std_msgs: ros predefined data types

　　

 

 

catkin_make:

　　package.xml : Organization ROS package, the package naming names, dependencies

　　　　　　　　　<name></name>

　　　　　　　　　<build_depend></build_depend>

　　　　　　　　　<run_depend></run_depend>

 　　　　　　　　

　　The CMakeLists.txt  : A simple example is as follows

cmake_minimum_required(VERSION 2.8.3)
project(demo-proj1-nodes) # package name

find_package(catkin REQUIRED COMPONENTS
    roscpp
    std_msgs
)

catkin_package(
#  INCLUDE_DIRS include
#  LIBRARIES my_minimal_nodes
#  CATKIN_DEPENDS roscpp std-msgs
#  DEPENDS system_lib
)

include_directories(
 include ${catkin_INCLUDE_DIRS}
)

add_executable(my_minimal_publisher src/minimal_publisher.cpp)
add_executable(my_minimal_publisher2 src/sleep_minimal_publisher.cpp)


target_link_libraries(my_minimal_publisher
   ${catkin_LIBRARIES}
)
target_link_libraries(my_minimal_publisher2
   ${catkin_LIBRARIES}
)

View Code

　　Compile command: catkin_make

　　

 

 　　After compilation there, devel and build two folders

rosrun:

　　At the outset environment variables:　source ./devel/setup.bash

         rosrun [Package-name] [executable name]