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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