ROS Basics (Python) – Basic ROS

ROS Basics (Python) – 4-Month Self-Study Course Syllabus

Course Description:

Welcome to “ROS Basics (Python),” a comprehensive 4-month self-study course designed to take you from a motivated beginner to an intermediate practitioner in the world of Robotic Operating System (ROS) using Python. This course demystifies the core concepts of ROS, providing you with the practical skills and theoretical understanding necessary to develop and manage robotic applications. Through a blend of clear explanations, essential vocabulary, and hands-on examples, you’ll learn how to navigate the ROS ecosystem, write Python nodes, understand communication mechanisms, and build foundational robotic behaviors. Whether you’re interested in mobile robots, manipulators, or complex AI systems, this course provides the essential building blocks for your robotics journey.

Primary Learning Objectives:

\Upon successful completion of this course, you will be able to:\ \ \Understand the fundamental architecture and philosophy of ROS.\ \Write and execute ROS nodes using Python.\ \Implement various ROS communication methods (topics, services, actions).\ \Utilize ROS tools for debugging, visualization, and simulation.\ \Create and manage ROS workspaces and packages.\ \Develop basic robotic applications that leverage ROS principles.\ \Integrate sensors and actuators within the ROS framework.\ \Apply ROS concepts to a cumulative robotics project.\ \

\\Necessary Materials:\\ \ \A computer running Ubuntu (preferably 20.04 LTS or newer) or a virtual machine with Ubuntu installed.\ \A stable internet connection.\ \Basic understanding of Python programming (variables, data types, control flow, functions, classes).\ \Familiarity with the Linux command line.\ \Optional: Access to a physical ROS-compatible robot (e.g., TurtleBot3) for enhanced hands-on experience, though all exercises can be completed in simulation.\ \

Course Content

Month 1: Foundations of ROS

\\Week 1: Introduction to ROS and the ROS Ecosystem\\ \ \\Title:\ Unveiling ROS: Your First Steps in Robot Programming\ \\Learning Objectives:\
\ \Explain what ROS is and why it’s used in robotics.\ \Understand the key components of a ROS system (nodes, topics, messages).\ \Set up a ROS environment on your machine.\ \ \ \\Key Vocabulary:\
\ \\ROS (Robot Operating System):\ A flexible framework for writing robot software.\ \\Node:\ An executable process in ROS that performs computation.\ \\Topic:\ A named bus over which nodes exchange messages.\ \\Message:\ A data structure used for communication over topics.\ \\Master (roscore):\ The central hub of a ROS system, enabling communication between nodes.\ \\Package:\ The primary organization unit of ROS software.\ \ \ \\Lesson Content:\
\ \\What is ROS?\ We’ll begin by exploring the philosophy behind ROS, its open-source nature, and its advantages for developing complex robotic applications. We’ll discuss how ROS acts as a middleware, providing standardized communication, tools, and libraries.\ \\Key Concepts Explained:\ Dive deeper into the fundamental building blocks: nodes as independent programs, topics for anonymous message passing, and messages as the structured data exchanged between nodes. We’ll use analogies to make these concepts relatable.\ \\Setting Up Your ROS Environment:\ A step-by-step guide to installing ROS (e.g., Noetic on Ubuntu 20.04) and configuring your workspace. This includes source installation and setting up environment variables.\ \ \ \\Practical Hands-on Examples:\
\ \Install ROS Noetic on your Ubuntu system.\ \Initialize a ROS workspace.\ \Run \roscore\ and observe its output.\ \Run the \turtlesim\ simulation and control the turtle using keyboard commands, observing the nodes and topics using \rosnode list\ and \rostopic list\.\ \ \ \

\\Week 2: ROS Nodes and Basic Python Programming for ROS\\ \ \\Title:\ Bringing Robots to Life: Writing Your First ROS Nodes in Python\ \\Learning Objectives:\
\ \Create a basic ROS Python package.\ \Write a simple ROS Python node to publish messages.\ \Write a simple ROS Python node to subscribe to messages.\ \ \ \\Key Vocabulary:\
\ \\Publisher:\ A node that sends messages on a topic.\ \\Subscriber:\ A node that receives messages from a topic.\ \\\rospy\:\ The Python client library for ROS.\ \\\catkin\_make\:\ The build system used by ROS.\ \\\setup.py\:\ A file in Python packages used for installation and configuration.\ \ \ \\Lesson Content:\
\ \\Creating a ROS Package:\ Learn the structure of a ROS package and how to create one using \catkin\_create\_pkg\. We’ll focus on setting up the necessary \CMakeLists.txt\ and \package.xml\ files for Python nodes.\ \\Publishers in Python:\ Understand how to instantiate a \rospy.Publisher\ object, define the message type, and publish data at a specified rate. We’ll cover the \rospy.init\_node()\ function and the importance of unique node names.\ \\Subscribers in Python:\ Learn how to create a \rospy.Subscriber\ object, specify the topic and message type, and define a callback function to process incoming messages.\ \ \ \\Practical Hands-on Examples:\
\ \Create a new ROS package named \my\_first\_ros\_pkg\.\ \Write a Python node that publishes “Hello ROS\!” messages to a new topic \/my\_topic\ at 1 Hz.\ \Write another Python node that subscribes to \/my\_topic\ and prints the received messages to the console.\ \Run both nodes simultaneously and verify communication using \rostopic echo /my\_topic\.\ \ \ \

\\Week 3: ROS Messages and Services\\ \ \\Title:\ Structured Communication: Understanding ROS Messages and Services\ \\Learning Objectives:\
\ \Define custom ROS message types.\ \Implement ROS services for request/response communication.\ \Understand the difference between topics and services.\ \ \ \\Key Vocabulary:\
\ \\\.msg\ file:\ A file used to define custom message types.\ \\\.srv\ file:\ A file used to define custom service types.\ \\Service Server:\ A node that provides a service.\ \\Service Client:\ A node that requests a service.\ \\Request:\ The input data sent to a service.\ \\Response:\ The output data returned by a service.\ \ \ \\Lesson Content:\
\ \\Custom Message Types:\ Explore how to create \.msg\ files to define your own data structures for topics, allowing for more complex and organized data exchange. Learn how to generate the necessary Python classes from these definitions.\ \\ROS Services: Request/Response:\ Understand the synchronous communication model of ROS services, where a client sends a request and waits for a response from a server. We’ll discuss scenarios where services are more appropriate than topics.\ \\Implementing Services in Python:\ Step-by-step guide to writing a service server and a service client using \rospy\. We’ll cover how to define \.srv\ files and implement the callback function for the service server.\ \ \ \\Practical Hands-on Examples:\
\ \Define a custom message type \TwoFloats.msg\ containing two float64 numbers.\ \Modify your publisher/subscriber nodes to use this custom message type.\ \Define a custom service type \AddTwoInts.srv\ that takes two integers and returns their sum.\ \Create a service server node that implements \AddTwoInts\.\