Beginner_tutorials

ROS Beginner tutorials as part of ENPM808x

Overview

• This repo demos a simple publisher and subscriber.
• References were used from http://wiki.ros.org/ROS/Tutorials.
• This repo also demos the use of Ros service.
• On running demo.launch, after 7 seconds, the client(present in listener.cpp) sends a request to the server to change the message in the publisher ( in talker.cpp). This changes the message being published which can be seen in terminal prints
• User can also change frequency of publish during launch.
• Note the use of 5 levels of logging as well.
• Added a unit testing file as well
• Added a TF broadcaster
• Added rosbag recording

rqt_console screenshot

Build Requirements

• CMake
• catkin
• ROS - Melodic
• Ubuntu 18.04

Build Instruction

mkdir -p ~/catkin_ws/src
cd ~/catkin_ws/
catkin_make
source devel/setup.bash
cd src/
git clone --recursive https://github.com/vishnuu95/beginner_tutorials.git
git checkout main
cd ..
catkin_make
source ~/catkin_ws/devel/setup.bash

Run Instruction

roslaunch beginner_tutorials demo.launch

The above will launch the 2 nodes and the talker will publish at 10hz default.

roslaunch beginner_tutorials demo.launch pub_freq:=<input your frequency value here as an Integer>

• The above will launch the 2 nodes and the talker will publish at the input frequency chosen by you. Also, a rosbag is recorded in the bags folder. The duration of record can be specified in the launch file.
• The above will also publish to /tf
• To check the published transform, do a simple

rostopic echo /tf

You should see the transform with parent as "world" and child as "talk"

cd ~/catkin_make
catkin_make run_tests_beginner_tutorials

The above will run unit tests to test the ros service that the talker has.