How can you use ROS to control multiple robots at once?

1 What is ROS?

ROS is not a typical operating system, but rather a middleware that runs on top of other operating systems, such as Linux, Windows, or MacOS. ROS allows you to communicate with different parts of a robot, such as sensors, actuators, controllers, and algorithms, using a common language and interface. ROS also enables you to reuse and share code across different robots and platforms, thanks to its modular and distributed architecture.

2 Why use ROS for multi-robot systems?

One of the main advantages of using ROS for multi-robot systems is that it simplifies the communication and coordination among robots. ROS provides several mechanisms for exchanging messages, such as topics, services, and actions. Topics are streams of data that can be published and subscribed by different nodes, which are the basic units of computation in ROS. Services are requests and responses that can be made between nodes. Actions are tasks that can be executed by nodes and monitored by other nodes. These mechanisms allow you to send commands, receive feedback, and synchronize behaviors among robots.

3 How to set up a multi-robot system with ROS?

To set up a multi-robot system with ROS, you need to follow some steps. First, you need to install ROS on each robot and on a central computer that will act as the master node. The master node is responsible for managing the network of nodes and topics in the system. Second, you need to configure the network settings of each robot and the master node, so that they can communicate with each other. You can use the ROS_HOSTNAME and ROS_MASTER_URI environment variables to specify the IP addresses and ports of each device. Third, you need to launch the ROS nodes and topics on each robot and on the master node. You can use the roslaunch or rosrun commands to start the nodes and topics. You can also use the roscore command to start the master node.

4 How to control a multi-robot system with ROS?

To control a multi-robot system with ROS, you need to use the appropriate message types and protocols for each task. For example, if you want to move the robots to a certain position, you can use the geometry_msgs/Twist message type and publish it to the /cmd_vel topic of each robot. If you want to monitor the status of the robots, you can use the nav_msgs/Odometry message type and subscribe to the /odom topic of each robot. If you want to perform a complex action, such as picking up an object, you can use the actionlib_msgs/Goal message type and send it to the /pick_up action server of each robot.

5 What are some examples of multi-robot systems with ROS?

There are many examples of multi-robot systems with ROS, from research projects to commercial applications. For instance, the TurtleBot3 is a low-cost and modular robot suitable for education and research that can be controlled by a single computer or a network of computers using ROS. The Clearpath Robotics Husky is a rugged and versatile robot for outdoor exploration and mapping that can be integrated with other robots and sensors using ROS. The Amazon Robotics Kiva is a fleet of robots designed for warehouse automation and logistics that can be coordinated and managed by a central system using ROS.

6 How to learn more about ROS and multi-robot systems?

If you're interested in learning more about ROS and multi-robot systems, there are many resources available online. The official ROS website offers documentation, tutorials, and community forums. Additionally, the ROS wiki provides information about packages, nodes, topics, and message types. Furthermore, ROS books such as Programming Robots with ROS and Mastering ROS for Robotics Programming provide comprehensive and practical guides. Finally, courses like The Construct and Robot Ignite Academy offer interactive and hands-on lessons.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?