ROSIntegration Plugin for Unreal Engine 4

This plugin adds ROS support to your Unreal Engine Project. It is designed to be used on different common platforms. Currently, Windows and Linux are directly supported.

The connection to the ROS world will be accomplished through http://wiki.ros.org/rosbridge_suite and https://github.com/sanic/rosbridge2cpp

This plugin is currently mainly maintained for Unreal Engine 4. Even though functionality might work under UE5, we see UE4 as a first class citizen on our master branch.

Description

This Plugin contains the basic data structures to enable the user to communicate with a running roscore. Currently, ROS Topics and ROS Services are supported.

To boost the performance for big messages (Image Streams for example), this plugin utilizes http://bsonspec.org/ to transfer binary data in a compact manner.

The core communication library behind this plugin is https://github.com/sanic/rosbridge2cpp, which allows the core communication capabilities to be developed, tested and improved by people who are not necessarily using it with Unreal Engine.

ROS Functionality can be added to UObjects or AActors by using functions like Advertise/Subscribe/Publish on the ROS Wrapper classes or in the form specific Unreal ActorComponents. This currently includes an ActorComponent that can be added to AActors to easily publish their coordinates to TF. If you need Vision Support in your Unreal Project, you can also add the ROSIntegrationVision Plugin (https://github.com/code-iai/ROSIntegrationVision/) which is compatible with this Plugin.

Communication with ROS is achieved by communicating with rosbridge_suite (Unreal Engine <--> rosbridge <--> ROS Nodes). This plugin supports using both TCP and websocket protocols to communicate with rosbridge. The plugin also supports both ROS1 and ROS2 connections.

Citations

If you are using this Plugin in an academic context and you want to cite us, we would be happy if you could use the following reference:

<pre> @inproceedings{mania19scenarios, title = {A Framework for Self-Training Perceptual Agents in Simulated Photorealistic Environments}, author = {Patrick Mania and Michael Beetz}, year = {2019}, booktitle = {International Conference on Robotics and Automation (ICRA)}, address = {Montreal, Canada} } </pre>

Dependencies of this Plugin

This Plugin utilizes BSON to achieve higher transferrates for binary data. It uses http://mongoc.org/libbson/ to encode and decode the whole ROS communication protocol. Since BSON is not included in Unreal Engine (yet), its code has to be added to this plugin. Currently, this plugin comes with a pre-compiled libbson for Windows x64 and Linux x64 which doesn't need any additional configuration.

To enable the communcation between Unreal and ROS, you will need a running ROSBridge (https://github.com/RobotWebTools/rosbridge_suite) with bson_mode. Note: Please use rosbridge with version=>0.8.0 to get full BSON support.

The recommended way to install rosbridge is from source (requires the rosauth package):

sudo apt-get install ros-ROS1_DISTRO-rosauth # Replace ROS1_DISTRO with the distro you are using
cd ~/ros_workspace/
source devel/setup.bash
cd src/
git clone -b ros1 https://github.com/RobotWebTools/rosbridge_suite.git
cd ..
catkin_make
source devel/setup.bash

Even though you could install rosbridge using apt via:

sudo apt-get install ros-ROS1_DISTRO-rosbridge-suite # Replace ROS1_DISTRO with the distro you are using

there have been numersous issues where these apt packages do not reflect the code in the ros1 branch. Hence, it is best to install from source. After installing rosbridge, you can enable the bson_mode like this:

roslaunch rosbridge_server rosbridge_tcp.launch bson_only_mode:=True

How to verify the rosbridge-UE4 connection: Make sure UE4 is configured to use the ROSIntegrationGameInstance (see below) and set the connection parameters. If UE4 and rosbridge are both running, then you should see the rosbridge node subscribe to two topics with the prefix /unreal_ros/. If you do NOT see this, then you likely have a problem with your rosbridge installation.

In our testing, we usually installed rosbridge on a Ubuntu Linux with ROS while the UE4 with ROSIntegration can be run on a Windows or Linux hosts. ROSBridge and UE4 with ROSIntegration don't need to be run on the same machine. So in order to run UE4 with ROSIntegration on Windows, you can either install a Linux Virtual Machine on your Windows Hosts or have a seperate, physical machine with Linux running in your network.

This plugin has previously been tested with Unreal Engine versions;

4.17.3
4.18.2
4.18.3
4.19.1, 4.19.2
4.20.3
4.23 (by Luigi Freda, fixed bugs with smart pointer management)
4.24
4.25
4.26

Please note that this list is a tracker of which UE4 versions have been previously tested. It is not guaranteed that the most recent version of ROSIntegration is working with all previous UE4 versions.

Usage

Setting up the plugin

Create a new C++ Unreal Project, or open your existing project. Please note that the Plugin might not get compiled automatically in BP-only Projects (see this Issue).
Add this repository to your Plugins/ Folder in your Unreal project (copy the folder in so your structure looks like MyUnrealProject/Plugins/ROSIntegration/ROSIntegration.uplugin
Activate the Plugin in your UE4 project by opening your project and go to Edit -> Plugins. Search for ROSIntegration in the "other" section and activate it.
Restart the editor and check that the code for the new plugin is built.
To specify your ROSBridge server, you have to create a custom GameInstance that inherits from ROSIntegrationGameInstance
Find ROSIntegrationGameInstance in the Content browser (you might need to enable 'View Options' > 'Show Plugin Content' in the bottom right of the content browser).
Right click and create a new C++ or Blueprint class based on ROSIntegrationGameInstance
Open your new C++ class / Blueprint object and configure the rosbridge connection properties:
- ROSBridgeServerProtocol: The communication protocol to use with rosbridge. Options are "tcp" or "ws".
- ROSBridgeServerHosts: A list of rosbridge server IP addresses. Each element pairs with the corresponding element in ROSBridgeServerPorts.
  - Note 1: In an older version, this was just a single value ROSBridgeServerHost. Now, you can connect to any number of rosbridge servers.
  - Note 2: If the number of elements in this array differs from the length of ROSBridgeServerPorts, then the unpaired elements will be skipped. And if you remove all entries in this array, then the plugin will use a default value of "127.0.0.1".
- ROSBridgeServerPorts A list of rosbridge server ports. Each element pairs with the corresponding element in ROSBridgeServerHosts.
  - Note 1: In an older version, this was just a single value ROSBridgeServerPort. Now, you can connect to any number of rosbridge servers.
  - Note 2: If the number of elements in this array differs from the length of ROSBridgeServerHosts, then the unpaired elements will be skipped. And if you remove all entries in this array, then the plugin will use a default value of 9090.
- ROSVersion: Indicate the ROS version that you are using. Only options are 1 or 2.
Open Project Settings > Maps and Modes, and set the GameInstance to match your new GameInstance object, not ROSIntegrationGameInstance
Don't forget to save everything (Ctrl + Shift + S)
In some cases (for example on Linux), it might be necessary to call the Generate Project Files action on UE4 in order to fetch the new header files for the plugin. Reference: https://wiki.unrealengine.com/Generate_Visual_Studio_Project or https://wiki.unrealengine.com/Building_On_Linux#Generating_project_files_for_your_project

Build

Run the following:

[Run UAT script] BuildPlugin -Plugin="[FULL PATH]/ROSIntegration.uplugin" -TargetPlatform=[Platform] -Package="[Desired Location]" -Rocket

UE may create a HostProject for the plugin, in which case, you'll find the plugin built inside HostProject/Plugins

Link to Plugins directory of your project
Add plugin to build.cs

[Public/Private]DependencyModuleNames.AddRange(new string[] { "ROSIntegration" });

Add plugin to uproject (may be performed via Editor GUI as well)

"Plugins": [
    {
      "Name": "ROSIntegration",
      "Enabled": true
    }
]

C++ Topic Publish Example

To get started, you can create a new C++ Actor and let it publish a message once at the BeginPlay Event. Add the following code into the BeginPlay() method of any actor that is put into to your world to see if the connection to ROS works:

#include "ROSIntegration/Classes/RI/Topic.h"
#include "ROSIntegration/Classes/ROSIntegrationGameInstance.h"
#include "ROSIntegration/Public/std_msgs/String.h"

// Initialize a topic
UTopic *ExampleTopic = NewObject<UTopic>(UTopic::StaticClass());
UROSIntegrationGameInstance* rosinst = Cast<UROSIntegrationGameInstance>(GetGameInstance());
ExampleTopic->Init(rosinst->ROSIntegrationCore, TEXT("/example_topic"), TEXT(

ROSIntegration

Install / Use

README