Introductin to Robot Operating System (ROS)

[  autonomous  middleware  ] 24 Feb 2023 • 6 min read

Introduction

Robot Operating System (ROS) is a powerful software framework for building and programming robots. ROS provides a flexible and modular architecture for building robot software, and includes a wide range of tools and libraries for tasks such as robot control, perception, and navigation. ROS was first introduced in 2007 by Willow Garage, a research lab in California, and has since become a popular choice for robotics researchers and developers around the world.

ROS Architecture

At its core, ROS is a distributed software system that consists of a set of independent nodes that communicate with each other through a publish-subscribe messaging system. Each node is a self-contained program that performs a specific task, such as reading data from sensors, processing data, or controlling robot actuators. Nodes can be written in a variety of programming languages, including C++, Python, and Java.

Nodes communicate with each other through topics, which are named channels for transmitting messages. A node that wants to send a message on a topic publishes the message to the topic, while other nodes that are interested in receiving messages on that topic subscribe to the topic. This publish-subscribe model allows nodes to communicate with each other in a flexible and asynchronous manner.

ROS also includes a parameter server, which is a central repository for storing and retrieving configuration parameters. Nodes can read and write parameters to the parameter server, which allows for easy configuration and tuning of robot software.

ROS also includes a powerful logging system, which allows nodes to log messages at different severity levels. These logs can be used for debugging and analysis, and can be saved to disk or transmitted over the network.

ROS Tools and Libraries

One of the strengths of ROS is its wide range of tools and libraries for various robotics tasks. These tools and libraries are organized into packages, which can be installed and used by developers as needed.

Some of the key packages in ROS include:

• Robot control: ROS includes packages for controlling robots, such as the ros_control and moveit packages. These packages provide interfaces for controlling robot joints and end-effectors, and for planning and executing complex motion trajectories.

• Perception: ROS includes packages for processing sensor data and extracting information about the robot’s environment. These packages include libraries for computer vision, point cloud processing, and object recognition.

• Navigation: ROS includes packages for planning and executing robot navigation, such as the navigation and slam_gmapping packages. These packages provide interfaces for mapping the robot’s environment, localizing the robot within the map, and planning and executing navigation paths.

• Manipulation: ROS includes packages for controlling robot manipulators, such as the robotiq and franka_ros packages. These packages provide interfaces for controlling grippers, performing force sensing and control, and executing manipulation tasks.

• Simulation: ROS includes packages for simulating robots and their environments, such as the gazebo and ros2_control packages. These packages allow developers to test and validate their robot software in a simulated environment before deploying it on a real robot.

ROS also includes a variety of other tools and libraries, such as the rosbag tool for recording and replaying data, the rviz visualization tool for displaying robot data, and the catkin build system for building and managing ROS packages.

ROS Applications

ROS has numerous applications in various industries and domains, including:

• Manufacturing: ROS is used in manufacturing for tasks such as robot assembly, material handling, and quality control.

• Healthcare: ROS is used in healthcare for tasks such as robot-assisted surgery, rehabilitation, and patient monitoring.

• Agriculture: ROS is used in agriculture for tasks such as crop monitoring, soil analysis, and precision agriculture.

• Service Robotics: ROS is used in service robotics for the development of robots that can assist with tasks such as cleaning, security, and hospitality.

• Education and Research: ROS is widely used in academic and research settings for teaching robotics, conducting research, and developing new robot applications. ROS provides a flexible and modular framework that allows researchers to easily build and test new algorithms and approaches in a wide range of robotics domains.

ROS also has a vibrant and active community of developers and users, who contribute to the development and improvement of the system. The ROS community has developed a wide range of open source packages and libraries that can be used for a variety of robotics applications.

ROS1 vs. ROS2

ROS has undergone significant changes since its initial release, with the development of a new version of the system, ROS2. ROS2 was introduced in 2014 as an evolution of ROS, with a focus on improving the system’s scalability, reliability, and real-time performance.

Some of the key differences between ROS1 and ROS2 include:

• Communication: ROS2 uses a new middleware called Data Distribution Service (DDS) for communication, which provides better reliability and real-time performance compared to ROS1’s TCP-based communication.

• Multi-Robot Systems: ROS2 has better support for multi-robot systems, with features such as a decentralized discovery and naming system, and improved message passing performance.

• Security: ROS2 includes improved security features, such as support for encrypted communication and user authentication.

• Language Support: ROS2 includes better support for programming languages other than C++ and Python, including Java and Rust.

• Real-Time Performance: ROS2 includes features such as a real-time executor and support for real-time scheduling, which makes it suitable for applications that require deterministic real-time performance.

Despite these differences, ROS1 and ROS2 are still compatible with each other, which means that ROS1 packages can be used in ROS2 systems with some modifications. However, ROS2 packages cannot be used in ROS1 systems.

Conclusion

Robot Operating System (ROS) is a powerful software framework for building and programming robots. ROS provides a flexible and modular architecture for building robot software, and includes a wide range of tools and libraries for tasks such as robot control, perception, and navigation. ROS has numerous applications in various industries and domains, and is widely used in academic and research settings for teaching robotics, conducting research, and developing new robot applications. The development of ROS2 has improved the system’s scalability, reliability, and real-time performance, making it a promising choice for future robot applications.