本文主要部分来源于ROS官网的Tutorials.
Ubuntu install of ROS Kinetic
# Setup your sources.list sudo sh -c 'echo "deb http://packages.ros.org/ros/ubuntu $(lsb_release -sc) main" > /etc/apt/sources.list.d/ros-latest.list' # Set up your keys sudo apt-key adv --keyserver hkp://ha.pool.sks-keyservers.net:80 --recv-key 421C365BD9FF1F717815A3895523BAEEB01FA116 # Installation sudo apt-get update sudo apt-get install ros-kinetic-desktop-full # Desktop-Full Install: (Recommended) # Initialize rosdep sudo rosdep init rosdep update # Environment setup, so ROS environment variables are automatically added to your bash session every time a new shell is launched echo "source /opt/ros/kinetic/setup.bash" >> ~/.bashrc source ~/.bashrc # Install this tool and other dependencies for building ROS packages sudo apt-get install python-rosinstall python-rosinstall-generator python-wstool build-essential
Configuring Your ROS Environment
# check to ensure that environment variables like ROS_ROOT and ROS_PACKAGE_PATH are set printenv | grep ROS source /opt/ros/kinetic/setup.bash # if no ROS variable are set, run this command # Create a ROS Workspace (use the recommended catkin) mkdir -p ~/catkin_ws/src cd ~/catkin_ws/ catkin_make
# source your new setup.*sh file when a new shell is launched
echo 'source /home/youruser/catkin_ws/devel/setup.bash' >> ~/.bashrc source ~/.bashrc echo $ROS_PACKAGE_PATH # you will see /home/youruser/catkin_ws/src:/opt/ros/kinetic/share
Navigating the ROS Filesystem
sudo apt-get install ros-kinetic-ros-tutorials rospack find roscpp # rospack find [package_name], returns the path to package roscd roscpp pwd # You can see that YOUR_INSTALL_PATH/share/roscpp is the same path that rospack find gave in the previous example echo $ROS_PACKAGE_PATH # ROS_PACKAGE_PATH should contain a list of directories where you have ROS packages separated by colons roscd roscpp/cmake # roscd can also move to a subdirectory of a package or stack pwd roscd log # take you to the folder where ROS stores log files # Note that if you have not run any ROS programs yet, this will yield an error saying that it does not yet exist. rosls roscpp_tutorials # rosls is part of the rosbash suite. It allows you to ls directly in a package by name rather than by absolute path. # Tab Completion roscd roscpp_tut<<< now push the TAB key >>>
Creating a ROS Package
cd ~/catkin_ws/src # catkin_create_pkg <package_name> [depend1] [depend2] [depend3] catkin_create_pkg beginner_tutorials std_msgs rospy roscpp # create a new package called 'beginner_tutorials' which depends on std_msgs, roscpp, and rospy # build the packages in the catkin workspace cd ~/catkin_ws catkin_make # To add the workspace to your ROS environment you need to source the generated setup file . ~/catkin_ws/devel/setup.bash rospack depends1 beginner_tutorials # First-order dependencies roscd beginner_tutorials cat package.xml # These dependencies for a package are stored in the package.xml file rospack depends beginner_tutorials # Indirect dependencies， rospack can recursively determine all nested dependencies
Building a ROS Package
cd ~/catkin_ws/ ls src catkin_make # build all catkin projects found in the src folder. catkin_make install # (optionally) ls
Understanding ROS Nodes
sudo apt-get install ros-kinetic-ros-tutorials # install a lightweight simulator
roscore # the first thing you should run when using ROS
rosnode list # lists active nodes
rosnode info /rosout # display information about a specific node
# in a new terminal:
rosrun turtlesim turtlesim_node # You will see the turtlesim window
# in a new termina
rosnode list # lists active nodes
rosrun turtlesim turtlesim_node __name:=my_turtle # change the node's name to my_turtle
rosnode list # lists active nodes
rosnode ping my_turtle # test that it's up
Review
- Nodes: A node uses ROS to communicate with other nodes. A node really isn't much more than an executable file within a ROS package.
- Messages: ROS data type used when subscribing or publishing to a topic.
- Topics: Nodes can publish messages to a topic as well as subscribe to a topic to receive messages.
- Master: Name service for ROS (i.e. helps nodes find each other)
- rosout: ROS equivalent of stdout/stderr
- roscore: Master + rosout + parameter server (parameter server will be introduced later)
You may have noticed a pattern with the naming of the ROS tools，This naming pattern holds for many of the ROS tools.
- rospack = ros + pack(age)
- roscd = ros + cd
- rosls = ros + ls
- roscore = ros+core : master (provides name service for ROS) + rosout (stdout/stderr) + parameter server (parameter server will be introduced later)
- rosnode = ros+node : ROS tool to get information about a node.
- rosrun = ros+run : runs a node from a given package.