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).

Here's a video of the very first successful run of ROS 2 follower: https://www.youtube.com/watch?v=YTlls9yHZog.

This is very much a work in progress and there's plenty of functionality present in the ROS 1 equivalent system that's currently missing or disabled, but it's an important step.

We're assuming here 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.

Installation

Install some dependencies

sudo apt-get install ros-kinetic-kobuki-driver ros-kinetic-kobuki-ftdi ros-kinetic-common-msgs ros-kinetic-astra-camera libusb-1.0.0-dev libudev-dev

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

Get the ROS 2 code

Follow the usual instructions for getting ROS 2 code. Be sure to install OpenSplice as one of the DDS implementations if you want to run the follower demo. Next, add a couple of repositories:

cd ~/ros2_ws/src
git clone https://github.com/ros2/turtlebot2_demo.git
git clone https://github.com/ros2/ros_astra_camera.git

Build the ROS 2 code, including the new nodes

# We'll eventually want to use the ROS 1 bridge, too
. /opt/ros/kinetic/setup.bash
cd ~/ros2_ws
./src/ament/ament_tools/scripts/ament.py build -s

Configure a couple of things

# Astra device rule
cd ~/ros2_ws/src/ros_astra_camera
sudo cp 56-orbbec-usb.rules /etc/udev/rules.d
# copy across the udev rules for kobuki
sudo cp `rospack find kobuki_ftdi`/57-kobuki.rules /etc/udev/rules.d
sudo service udev reload
sudo service udev restart

Run the new nodes

Joystick teleop

Try the launch file:

. ~/ros2_ws/install/setup.bash
launch ~/ros2_ws/src/turtlebot2_demo/turtlebot2_drivers/launch/turtlebot_joy.py

Or, run the nodes separately:

. ~/ros2_ws/install/setup.bash
kobuki_node

. ~/ros2_ws/install/setup.bash
joy_node

Follower

Try the launch file:

. ~/ros2_ws/install/setup.bash
launch ~/ros2_ws/src/turtlebot2_demo/turtlebot2_drivers/launch/turtlebot_follow.py

Or, run the nodes separately. Note that here we're specifically requesting the OpenSplice variants of the nodes; this is to ensure that we use an RMW implementation that supports large message transfer, which is required for the depth image produced by the Astra camera. This constraint will be relaxed in the future.

. ~/ros2_ws/install/setup.bash
kobuki_node__rmw_opensplice_cpp

. ~/ros2_ws/install/setup.bash
astra_camera_node__rmw_opensplice_cpp

. ~/ros2_ws/install/setup.bash
follower__rmw_opensplice_cpp

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:

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.
Astra driver: we forked and ported the existing ROS 1 package (there's no roscpp-independent package separation).
Joystick driver: we wrote a simple rclcpp node from scratch (Linux-only for now).
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.

nuclearsandwich / turtlebot2_demo