stretch_tutorials/ros2

Tutorial Track: Stretch ROS 2 (Beta)

Robot Operating System 2 (ROS 2)

ROS 2 is the successor to ROS, The ROS in ROS 2 stands for "robot operating system", but despite the name, ROS is not an operating system. It's a middleware framework that is a collection of transport protocols, development and debugging tools, and open-source packages.

As a transport protocol, ROS enables distributed communication via messages between nodes. As a development and debugging toolkit, ROS provides build systems that allow for writing applications in a wide variety of languages (Python and C++ are used in this tutorial track), a launch system to manage the execution of multiple nodes simultaneously, and command line tools to interact with the running system. Finally, as a popular ecosystem, there are many open-source ROS packages that allow users to quickly prototype with new sensors, actuators, planners, perception stacks, and more.

Despite the name, ROS is not an operating system. ROS is a middleware framework that is a collection of transport protocols, development and debugging tools, and open-source packages. As a transport protocol, ROS enables distributed communication via messages between nodes. As a development and debugging toolkit, ROS provides build systems that allow for writing applications in a wide variety of languages (Python and C++ are used in this tutorial track), a launch system to manage the execution of multiple nodes simultaneously, and command line tools to interact with the running system. Finally, as a popular ecosystem, there are many open-source ROS packages that allow users to quickly prototype with new sensors, actuators, planners, perception stacks, and more.

This tutorial track is for users looking to get familiar with programming Stretch robots via ROS 2. We recommend going through the tutorials in the following order:

Basics

	Tutorial	Description
1	Getting Started	Setup instructions for ROS 2 on Stretch
2	Introduction to ROS 2	Explore the client library used in ROS2
3	Introduction to HelloNode	Explore the Hello Node class to create a ROS2 node for Stretch
4	Teleoperating Stretch	Control Stretch with a Keyboard or a Gamepad controller.
5	Internal State of Stretch	Monitor the joint states of Stretch.
6	RViz Basics	Visualize topics in Stretch.
7	Nav2 Stack	Motion planning and control for mobile base.
8	Follow Joint Trajectory Commands	Control joints using joint trajectory server.
9	Perception	Use the Realsense D435i camera to visualize the environment.
10	ArUco Marker Detection	Localize objects using ArUco markers.
11	ReSpeaker Microphone Array	Learn to use the ReSpeaker Microphone Array.
12	FUNMAP	Fast Unified Navigation, Manipulation and Planning.

Other Examples

To help get you started on your software development, here are examples of nodes to have Stretch perform simple tasks.

	Tutorial	Description
1	Mobile Base Velocity Control	Use a python script that sends velocity commands.
2	Filter Laser Scans	Publish new scan ranges that are directly in front of Stretch.
3	Mobile Base Collision Avoidance	Stop Stretch from running into a wall.
4	Give Stretch a Balloon	Create a "balloon" marker that goes where ever Stretch goes.
5	Print Joint States	Print the joint states of Stretch.
6	Store Effort Values	Print, store, and plot the effort values of the Stretch robot.
7	Capture Image	Capture images from the RealSense camera data.
8	Voice to Text	Interpret speech and save transcript to a text file.
9	Voice Teleoperation of Base	Use speech to teleoperate the mobile base.
10	Tf2 Broadcaster and Listener	Create a tf2 broadcaster and listener.
11	ArUco Tag Locator	Actuate the head to locate a requested ArUco marker tag and return a transform.
12	Obstacle Avoider	Avoid obstacles using the planar lidar.
13	Align to ArUco	Detect ArUco fiducials using OpenCV and align to them.
14	Deep Perception	Use YOLOv5 to detect 3D objects in a point cloud.
15	Avoiding Race Conditions and Deadlocks	Learn how to avoid Race Conditions and Deadlocks