ROS Integration

Most of the Ignition libraries use Ignition Transport to exchange data between different software components. This tutorial details how to interface with ROS, enabling the ability to use tools such as Rviz for robot or sensor visualization.

Important: The packages documented here used to have the ros1_ prefix instead of ros_. Please update your code accordingly in order to avoid adverse effects.

ros_ign_bridge to the rescue

ros_ign_bridge provides a network bridge which enables the exchange of messages between ROS 1 and Ignition Transport. Its support is limited to only certain message types. Please, read this README to verify if your message type is supported by the bridge.

How to install ros_ign_bridge

Binary install

The repository packages.osrfoundation.org hosts binary packages for Ubuntu Bionic. To install the binaries

sudo sh -c 'echo "deb http://packages.osrfoundation.org/gazebo/ubuntu-stable `lsb_release -cs` main" > /etc/apt/sources.list.d/gazebo-stable.list'
sudo apt-get install ros-ign-bridge

Source install

See the prerequisites and install section of the bridge documentation. This tutorial requires Ubuntu Bionic or newer.

Assuming that you have ROS Melodic, you can install all dependencies with:

sudo apt install ros-melodic-desktop ros-melodic-rqt-image-view libignition-common3-dev libignition-transport7-dev

Run the bridge and exchange images

In this example, we’re going to generate Ignition Transport images using Gazebo, that will be converted into ROS 1 images, and visualized with rqt_viewer.

First we start a ROS 1 roscore:

# Shell A:
. /opt/ros/melodic/setup.bash
roscore

Then we start Gazebo.

# Shell B:
ign gazebo -r camera_sensor.sdf

Gazebo should be running and publishing images over the /camera topic. Let’s verify it:

# Shell C:
ign topic -l | grep "^/camera"
/camera

Then we start the parameter bridge with the previous topic.

If you perform a from source installation, please source the setup.bash (not needed for binary packages):

# Shell D:
. ~/bridge_ws/install/setup.bash

Run the bridge:

# Shell D:
rosrun ros_ign_bridge parameter_bridge /camera@sensor_msgs/Image@ignition.msgs.Image

Now we start the ROS 1 GUI:

# Shell E:
. /opt/ros/melodic/setup.bash
rqt_image_view /camera

You should see the current images in rqt_image_view which are coming from Gazebo (published as Ignition Msgs over Ignition Transport).

The screenshot shows all the shell windows and their expected content (it was taken using ROS Melodic):