This repository contains the code and supporting files to run TurtleBot 2 demos using ROS 2. Due to reliance on existing Linux-only code and dependencies, these demos are intended for use only on Linux (that could change in the future).

This demo assumes that you have an Orbbec Astra depth camera. Extra work would be required to use the Kinect or Asus Xtion Pro. Without an Astra, you can still do joystick teleop. For instructions on how to setup your turtlebot please see Setup your turtlebot2

Installation

Installation from binaries

First, install ROS2 from binaries following these instructions

Then install the turtlebo2 demo specific packages:

sudo apt install ros-ardent-turtlebot2* ros-kinetic-kobuki-ftdi

Installation from source

This assumes that you have ROS Kinetic installed (or at lease have the ros apt repository in your sources)

First, install ROS2 from source following these instructions

Then get the turtlebo2 demos specific code:

cd <YOUR_ROS2_WORKSPACE>
wget https://raw.githubusercontent.com/ros2/turtlebot2_demo/ardent/turtlebot2_demo.repos
vcs import src < turtlebot2_demo.repos

Install some dependencies:

sudo apt-get install --no-install-recommends -y libboost-iostreams-dev libboost-regex-dev libboost-system-dev libboost-thread-dev libceres-dev libgoogle-glog-dev liblua5.2-dev libpcl-dev libprotobuf-dev libsdl1.2-dev libsdl-image1.2-dev libsuitesparse-dev libudev-dev libusb-1.0.0-dev libyaml-cpp-dev protobuf-compiler python-sphinx ros-kinetic-kobuki-driver ros-kinetic-kobuki-ftdi

Reason for each dependency:

• ros-kinetic-kobuki-driver : our ROS 2 kobuki driver builds on top of this package (and its dependencies)
• ros-kinetic-kobuki-ftdi : we use a udev rule from this package
• ros-kinetic-common-msgs : to support use of the ros1_bridge, we need the ROS 1 messages available (TODO: document use of the bridge to view depth images and other stuff)
• ros-kinetic-astra-camera : we're compiling our own ROS 2 fork of this package, so we don't actually need the ROS 1 version; we're installing it as a convenient way to ensure that all of its dependencies are installed

Build the ros2 code

For resource constrained platforms we will split the build into 2 steps to make sure not to overflow the memory

src/ament/ament_tools/scripts/ament.py build --isolated --symlink-install --parallel --skip-packages cartographer cartographer_ros ros1_bridge turtlebot2_amcl turtlebot2_drivers turtlebot2_follower turtlebot2_cartographer turtlebot2_teleop

Now the resource intensive packages and the ones depending on ROS1 packages:

source /opt/ros/kinetic/setup.bash
src/ament/ament_tools/scripts/ament.py build --isolated --symlink-install --parallel --only cartographer cartographer_ros turtlebot2_amcl turtlebot2_cartographer turtlebot2_drivers turtlebot2_follower turtlebot2_teleop --make-flags -j2 -l2

Go grab a coffee (or a meal if you compile on ARM)

Configure a couple of things

Setup the udev rules

Copy the astra udev rules

If you installed from binaries

If you installed from binary you'll need to download the udev rule by hand:

wget https://raw.githubusercontent.com/ros2/ros_astra_camera/ros2/56-orbbec-usb.rules

If you installed from source

cd ~/ros2_ws/src/ros2/ros_astra_camera

Copy the rules file

sudo cp 56-orbbec-usb.rules /etc/udev/rules.d

Copy the kobuki udev rule

sudo cp `rospack find kobuki_ftdi`/57-kobuki.rules /etc/udev/rules.d

Restart the udev service

sudo service udev reload
sudo service udev restart

Source your workspace

If installed from Debian packages

source /opt/ros/kinetic/setup.bash
source /opt/ros/ardent/setup.bash

If installed from source

source /opt/ros/kinetic/setup.bash
source ~/ros2_ws/install/local_setup.bash

You'll need to do this step for every terminal you use for these demos

Run the demos

Joystick teleop

This is a classic teleoperation demo where the robot can be driven around using a gamepad controller. Thie demo has been tested with logitech controllers and uses RB as a deadman, the left joystick for driving forward/backward and the right joystick for rotation. Try the launch file:

launch `ros2 pkg prefix turtlebot2_teleop`/share/turtlebot2_teleop/launch/turtlebot_joy.py

Or, run the nodes separately:

ros2 run turtlebot2_drivers kobuki_node

ros2 run joy joy_node

Note: this demo assumes that your controller is in D mode (switch on the back) and that the MODE led is on.

Follower

This demo uses the astra camera to detect blobs in the depthimage and follow them Try the launch file:

launch `ros2 pkg prefix turtlebot2_follower`/share/turtlebot2_follower/launch/turtlebot_follow.py

Or, run the nodes separately.

ros2 run turtlebot2_drivers kobuki_node

ros2 run astra_camera astra_camera_node -- -dw 320 -dh 240 -C -I

ros2 run turtlebot2_follower follower

Cartographer (mapping)

This demo is using Google cartographer to build a map of the environment. The resulting map can be visualized in RViz using the ros1_bridge (more information below).

Run the demo

Try the launch file:

launch `ros2 pkg prefix turtlebot2_cartographer`/share/turtlebot2_cartographer/launch/turtlebot_carto_2d.py

Visualize the results

The created map can be visualized in Rviz on a remote computer by using the dynamic bridge that converts messages between ROS1 and ROS2. This assumes that you have a ROS2 dynamic bridge on your system.

Installing the bridge

From binaries:

Setup your sources as explained on the setup sources section and then run

sudo apt update && sudo apt install ros-ardent-ros1-bridge

From source:

Build your ROS2 workspace as explained in these instructions.

Run the bridge

Terminal A:

. /opt/ros/kinetic/setup.bash
roscore

Terminal B:

. /opt/ros/kinetic/setup.bash
. <YOUR_ROS2_WORKSPACE>
ros2 run ros1_bridge dynamic_bridge

Terminal C:

. /opt/ros/kinetic/setup.bash
rosrun rviz rviz

Topics you can visualize in Rviz:

• the map on the topic /map
• the transforms on the topic /tf
• the depth images on the topic /depth
• the laserscans on the topic /scans

AMCL (localization)

See the AMCL demo README

Discussion

What's happening here compared to the ROS 1 versions of these demos? Well, it's 100% ROS 2, with no bridge or shim. We took 4 different approaches in building the different pieces:

1. Kobuki driver: we wrote a new, very small rclcpp node that calls into the existing kobuki driver packages, which are organized to be roscpp-independent. In this case, we're building on top of ROS 1 packages, but they don't use roscpp or other parts of the ROS 1 middleware, so we're just using them as supporting libraries.
2. Astra driver: we forked and ported the existing ROS 1 package (there's no roscpp-independent package separation).
3. Joystick driver: we wrote a simple rclcpp node from scratch (Linux-only for now).
4. Follower node: we created a new package into which we copied and then ported the ROS 1 follower nodelet.

As we start migrating more code to ROS 2, we'll discover more about these kinds of techniques and arrive at some best practices that we can recommend for similar projects.