Mastering with ROS: Turtlebot3 – A 4-Month Self-Study Course Syllabus

Course Description:

This comprehensive 4-month self-study course is meticulously designed to immerse motivated beginners and intermediate learners in the exciting world of robotics, leveraging the power of the Turtlebot3 and the Robot Operating System (ROS). Through hands-on experience, you will gain proficiency in programming, simulating, and controlling a mobile robot, establishing a robust foundation in core ROS concepts, autonomous navigation, sensor-based perception, and fundamental manipulation techniques. By the culmination of this course, you will possess the expertise to confidently develop and deploy ROS-based applications for the Turtlebot3, preparing you to tackle more intricate robotics challenges.

Primary Learning Objectives:

• Gain a deep understanding of the fundamental concepts of ROS and its modular architecture.
• Achieve proficiency in operating, programming, and troubleshooting the Turtlebot3 robot.
• Successfully implement basic navigation and mapping functionalities utilizing the ROS Navigation Stack.
• Explore and apply various perception techniques using common robotics sensors such as LiDAR and cameras.
• Develop and integrate custom ROS nodes and launch files for diverse robotic tasks.
• Apply all learned concepts to a comprehensive cumulative final project, involving the simulation and control of a Turtlebot3 in a complex, realistic environment.

Necessary Materials:

• A computer running Ubuntu 20.04 (or a later compatible version) with administrative privileges.
• ROS Noetic and ROS 2 Foxy (or later compatible distributions) properly installed and configured.
• Gazebo simulation environment (typically included with a standard ROS installation).
• Optional (highly recommended for enhanced practical experience): A physical Turtlebot3 robot (Burger or Waffle Pi model). Please note that all practical examples and exercises are designed to be fully executable within the Gazebo simulation environment if a physical robot is not available.
• A preferred text editor or Integrated Development Environment (IDE) such as VS Code or Sublime Text.
• A stable internet connection for accessing online documentation, resources, and community support.

Course Content

Weeks 1-2: Foundations of ROS and Turtlebot3 Basics

Lesson 1: Introduction to ROS and the Turtlebot3 Ecosystem

• Learning Objectives:
  • Comprehend the purpose and significance of ROS within the robotics landscape.
  • Become familiar with the fundamental ROS architecture, including nodes, topics, messages, services, and actions.
  • Identify and understand the core components of the Turtlebot3 robot and its seamless integration with ROS.
• Key Vocabulary:
  • ROS: Robot Operating System – a flexible framework providing libraries and tools for developing robot software.
  • Node: An executable process within ROS that performs a specific computational task.
  • Topic: A named communication channel over which ROS nodes exchange messages.
  • Message: A structured data format used for passing information between ROS nodes.
  • Service: A request/reply communication mechanism enabling nodes to offer and consume specific functionalities.
  • Action: A goal-oriented communication mechanism for long-running, asynchronous tasks.
  • Turtlebot3: A compact, affordable, and highly programmable mobile robot platform.
• Content:

  ROS is not a traditional operating system, but rather a powerful meta-operating system designed to streamline the development of sophisticated robot behaviors. It facilitates inter-process communication, abstracting away the complexities of low-level hardware interactions. The Turtlebot3 serves as an exceptional learning platform for ROS due to its small form factor, cost-effectiveness, and extensive community support. Available in two primary versions, Burger and Waffle Pi, both are capable of executing a diverse range of robotic tasks. This lesson will delve into how ROS empowers various functionalities on the Turtlebot3, such as precise motor control, efficient sensor data processing, and robust navigation.

• Practical Hands-on Examples:
  • Perform a complete installation of ROS Noetic (or a later version) and the Turtlebot3 simulation packages.
  • Successfully launch the Turtlebot3 Gazebo simulation environment.
  • Utilize rostopic list and rosnode list commands to inspect and explore the active topics and nodes within the running simulation.
  • Send basic control commands to the Turtlebot3 using rostopic pub to initiate movement within the simulated environment.

Lesson 2: ROS Filesystem and Core Tools

• Learning Objectives:
  • Effectively navigate the ROS filesystem hierarchy, including packages, metapackages, and workspaces.
  • Understand the purpose and practical application of essential ROS command-line tools.
  • Gain proficiency in creating and utilizing ROS launch files for orchestrating multiple nodes and processes.
• Key Vocabulary:
  • Package: The fundamental unit of organization in ROS, encompassing nodes, libraries, configuration files, and other resources.
  • Metapackage: A logical grouping that bundles related ROS packages together.
  • Workspace: A structured directory where ROS packages are organized, built, and managed.
  • Launch file: An XML-based file used to define, start, and configure multiple ROS nodes and other executables in a single operation.
• Content:

  The ROS filesystem is organized hierarchically, with packages forming the core building blocks. Each package encapsulates the necessary code and configuration for a specific robot functionality. Workspaces are indispensable for structuring your development environment, allowing for efficient management and building of multiple packages. ROS offers a comprehensive suite of command-line tools for introspection and manipulation of the ROS environment, including roscd, rosls, rosrun, and roslaunch. Launch files are particularly powerful, enabling the definition of complex system setups, including node arguments, topic remappings, and parameter configurations, all within a single XML file.

• Practical Hands-on Examples:
  • Create a new ROS workspace and a custom ROS package.
  • Develop a simple “Hello World” ROS node using either Python or C++.
  • Construct a launch file to effectively run your “Hello World” node.
  • Utilize rosrun to execute a single node and roslaunch to deploy your launch file.
  • Explore the contents of various official Turtlebot3 ROS packages using the roscd and rosls commands.

Weeks 3-4: ROS Communication Mechanisms

Lesson 3: Understanding ROS Topics and Messages

• Learning Objectives:
  • Develop a deeper understanding of ROS topics and their associated message types.
  • Learn the practical skills of publishing data to and subscribing to data from ROS topics.
  • Master the use of rostopic echo and rosmsg show for inspecting message contents in real-time.
• Key Vocabulary:
  • Publisher: A ROS node responsible for sending messages on a specific topic.
  • Subscriber: A ROS node configured to receive messages from a particular topic.
  • Message Type: The predefined data structure that dictates the format of messages exchanged on a topic.
• Content:

  Topics represent the most common and fundamental method for communication between ROS nodes. A node can actively publish messages on a designated topic, while other nodes can subscribe to that same topic to receive those messages. Messages are rigorously defined by specific data structures, ensuring consistent and reliable communication. A thorough understanding of message types is paramount for accurately interpreting the data being exchanged. Tools such as rostopic echo provide real-time inspection capabilities for messages, while rosmsg show offers a clear definition of any given message type.

• Practical Hands-on Examples:
  • Write a Python/C++ node that publishes a simple string message to a newly created custom topic.
  • Develop a separate node that subscribes to this custom topic and prints all received messages to the console.
  • Employ rostopic echo to visualize the messages being published in real-time.
  • Explore and understand common Turtlebot3 topics, such as /odom (odometry data) and /cmd_vel (velocity commands).
  • Publish velocity commands to the /cmd_vel topic to precisely control the Turtlebot3’s movement in simulation.

Lesson 4: ROS Services and Parameters

• Learning Objectives:
  • Grasp the conceptual framework of ROS services for request/reply communication patterns.
  • Implement both ROS service clients and service servers.
  • Understand and effectively utilize ROS parameters for dynamic configuration of nodes.
• Key Vocabulary:
  • Service Server: A ROS node that provides a specific service or functionality.
  • Service Client: A ROS node that sends a request to a service server and receives a response.
  • Service Type: The definition specifying the structure of both the request and response messages for a service.
  • ROS Parameter Server: A centralized, shared dictionary for storing and managing configuration parameters across ROS nodes.
• Content:

  While ROS topics are ideal for continuous data streams, ROS services are designed for request-reply interactions. A service server offers a particular functionality, which a service client can then invoke, sending a request and subsequently receiving a response. This mechanism is particularly