ROS Tutorial

• ROS beginner tutorials for the course ENPM808X.
• This is a simple ROS package with three nodes.

1. talker
2. listener
3. modifier

• This package demonstrates how ROS communication is accomplished through nodes and topics. Each publishing node advertises the message to a topic that any node can subscribe to. This ensures that multiple nodes read the message seamlessly. This project can be extended to have multiple talkers and listeners. Note: each node should have a unique name.

Additionally, we have a node called modify which demonstrates the ROS services to alter the value of talker message.

Dependencies

• ROS Indigo running on Ubuntu 14.04.
• If you do not have ROS, download the bash script here and run it as sudo. Note: This script assumes you're running Ubuntu 14.04.

Package Dependency

• std_msgs
• roscpp
• rospy
• message_generation

Build steps

• Open a terminal

mkdir -p catkin_ws/src
cd catkin_ws/src && catkin_init_workspace
git clone https://github.com/banuprathap/beginner_tutorials.git
cd ..
catkin_make
source ./devel/setup.bash

Running the demo

• In your terminal

roslaunch beginner_tutorials demo.launch

Also, you can specify frequency and the message using arg:=value. For example to launch the talker at 100Hz to publish test use,

roslaunch beginner_tutorials demo.launch message:="test" frequency:=100

Note: For the specified message to take effect, open a new terminal and run,

rosrun beginner_tutorials modify

Create Documentation

You will require rosdoc_lite package to create documents in ROS standards. You can get that by running

sudo apt-get install ros-indigo-rosdoc-lite

Once installed, run the following command replacing path with absolute path to the package in your file system. Assuming the catkin_ws is in your home directory, path would be ~/catkin_ws/src/beginner_tutorials/

rosdoc_lite path