ALFRED (Autonomous Labor Focused ROS Extensible Drone)

Just a fun project that allows you to control an iRobot Create 2 from a React.js web application, a native mobile application, a wireless Xbox controller, or even a smart watch.

The primary purpose of this project is to demonstrate a simple and foundational full-stack design of a ROS extensible ecosystem where robots on the same network can talk to one other as well as be controlled by any RESTful UI application.

Getting Started

Materials

• An iRobot Create 2
• A Raspberry Pi 4, hereby referred to as Alfred
• A separate machine (hereby referred to as The Batcomputer) that can support the Robot Operating System (ROS); ROS2 is not yet widely used enough for all of this project's dependencies to be built.
  • My host OS is Mac Monterey, which only suports ROS2, so I used a VirtualBox virtual machine, which can work as long you use a "bridged network adapter", a physical ethernet cable connection to your host machine, and explicitly map hostnames to local IP addresses on each device correctly.
  • All devices need to be on the same local network for the ROS messaging system to work properly.
• Xcode (if you own a Mac) is optional should you wish to run the iOS/SmartWatch POC.

Setup

Install ROS on each Machine

• Install Ubuntu Server 20.04 on your Raspberry Pi 4
  • Make sure you install Ubuntu Server, and not Raspbian or Ubuntu Desktop
• Install ROS on the Raspberry Pi 4 over SSH
  • The Noetic distribution of ROS was used for this project
  • Be sure to use the same version/distribution of ROS on ALL machines that will be part of the ROS network
• Install Ubuntu 20.04 on The Batcomputer
  • If you decide to use a virtual machine, like I did, make sure to connect an actual ethernet cable to your host machine, and change the network adapter for VM to be a "bridged network"
• Install ROS on The Batcomputer

Configure Environments

• Find the local IP address of Alfred and The Batcomputer with ifconfig. It should look something like 192.168.x.1 or 192.168.x.2.
• Edit the hostname mappings on Alfred with sudo nano /etc/hosts and make sure you have the following lines:

127.0.0.1    localhost
127.0.1.1    alfred
192.168.x.2  batcomputer

• On Alfred add the following lines to the end of ~/.bashrc then after you save run source ~/.bashrc:

source /opt/ros/noetic/setup.bash
export ROS_HOSTNAME=192.168.x.2
export ROS_MASTER_URI=http://batcomputer:11311

NOTE that ROS_HOSTNAME is set to the actual local IP address of Alfred, because otherwise, sensor topics won't be connected properly.

• Edit the hostname mappings on The Batcomputer with sudo nano /etc/hosts and make sure you have the following lines:

127.0.0.1    localhost
127.0.1.1    batcomputer
192.168.x.1  alfred

• On The Batcomputer add the following lines to the end of ~/.bashrc then after you save run source ~/.bashrc:

source /opt/ros/noetic/setup.bash
export ROS_HOSTNAME=batcomputer
export ROS_MASTER_URI=http://batcomputer:11311

To verify if your ROS environments are configured correctly:

• Launch ROS Core on The Batcomputer by just running the command roscore
• On Alfred run the command rostopic echo /batstuff
• Finally, in a second terminal window on The Batcomputer run the following command:

ubuntu@batcomputer$ rostopic pub -r 10 /batstuff std_msgs/String "I'll be home late, Alfred"

If you have configured your ROS environments correctly, the terminal on Alfred should start receiving messages from The Batcomputer at a rate of 10Hz.

Building the Code

Build ROS Packages on Alfred

• In order to build the ROS packages used by Alfred, you will need to move the src directory into your ROS workspace, which is typically ~/ros_catkin_ws. Create the workspace directory if you need to: mkdir -p ~/ros_catkin_ws/src.

ubuntu@alfred$ mkdir ~/opt
ubuntu@alfred$ cd ~/opt
ubuntu@alfred$ git clone https://github.com/NoodleOfDeath/alfred
ubuntu@alfred$ cp -rf alfred/src/alfred ~/ros_catkin_ws/src

• Next, you'll need to clone the ROS package projects for the iRobot Create 2

ubuntu@alfred$ cd ~/ros_catkin_ws/src
ubuntu@alfred$ git clone https://github.com/AutonomyLab/libcreate.git
ubuntu@alfred$ git clone https://github.com/AutonomyLab/create_robot.git
ubuntu@alfred$ ls
alfred create_robot libcreate

• Use rosdep to download dependencies and then catkin tools to build all of the ROS packages on Alfred:

ubuntu@alfred$ cd ~/ros_catkin_ws
ubuntu@alfred$ rosdep install --from-paths src
ubuntu@alfred$ rosdep update
ubuntu@alfred$ catkin build
...                                                                                                                        
[build] Summary: All 7 packages succeeded!                                                                                                                                                 
[build]   Ignored:   None.                                                                                                                                                                 
[build]   Warnings:  None.                                                                                                                                                                 
[build]   Abandoned: None.                                                                                                                                                                 
[build]   Failed:    None.                                                                                                                                                                 
[build] Runtime: 13.3 seconds total.

• Once the packages build successfully, plugin the USB cable for the iRobot Create 2 into the Raspbeery Pi, then run the following command on Alfred and you should hear the robot boot up:

ubuntu@alfred$ cd ~/ros_catkin_ws
ubuntu@alfred$ source devel/setup.bash
ubuntu@alfred$ roslaunch alfred alfred.launch
... logging to /home/ubuntu/.ros/log/7000dcd8-94b6-11ec-a63c-ebe27d46d47f/roslaunch-alfred-15936.log
Checking log directory for disk usage. This may take a while.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

started roslaunch server http://alfred:45035/
...
[ WARN] [1645649489.650718343]: link 'base_footprint' material 'Green' undefined.
[ WARN] [1645649489.666563810]: link 'base_footprint' material 'Green' undefined.
[ INFO] [1645649489.690201817]: CreateDriver Online
[ INFO] [1645649489.695118354]: [CREATE] "CREATE_2" selected
[ INFO] [1645649490.885812415]: [CREATE] Connection established.
[ INFO] [1645649490.886188947]: [CREATE] Battery level 33.51 %
[ INFO] [1645649491.466942727]: [CREATE] Ready.

Build Custom ROS .msg Package on The Batcomputer

A custom ROS msg format is used called Float32List. This package needs to be build on both Alfred (as you did already) and The Batcomputer. Copy the package source into the ROS workspace on The Batcomputer and simply run catkin build:

ubuntu@batcomputer$ mkdir -p ~/ros_catkin_ws/src
ubuntu@batcomputer$ mkdir ~/opt
ubuntu@batcomputer$ cd ~/opt
ubuntu@batcomputer$ git clone https://github.com/NoodleOfDeath/alfred
ubuntu@batcomputer$ cp -rf alfred/api/batcomputer/ros_pkgs/batcomputer ~/ros_catkin_ws/src
ubuntu@batcomputer$ cd ~/ros_catkin_ws
ubuntu@batcomputer$ catkin build

Run the Application Stack

The Batcomputer will be running ROS core, a FastAPI server, and a React.js web application.

• Make sure ROS core is running on The Batcomputer by running roscore in the terminal.
• In a second tab, run the subscriber node on The Batcomputer by running

ubuntu@batcomputer$ source cd ~/ros_catkin_ws/devel/setup.bash
ubuntu@batcomputer$ cd ~/opt/alfred/api/batcomputer
ubuntu@batcomputer$ ./sub.py

• Finally, in a third terminal tab, start the FastAPI instance on The Batcomputer either as a docker container or directly with uvicorn

ubuntu@batcomputer$ source cd ~/ros_catkin_ws/devel/setup.bash
ubuntu@batcomputer$ cd ~/opt/alfred/api/batcomputer
ubuntu@batcomputer$ uvicorn api:app --reload --host "0.0.0.0"
INFO:   Uvicorn running on http://0.0.0.0:8000 (Press CTRL+C to quit)
INFO:   Started reloader process [11995]
INFO:   topicmanager initialized

• Update node on The Batcomputer to 14+ or the React.js application will not work.

ubuntu@batcomputer$ sudo apt update
ubuntu@batcomputer$ curl -sL https://deb.nodesource.com/setup_14.x | sudo bash -
ubuntu@batcomputer$ cat /etc/apt/sources.list.d/nodesource.list
deb https://deb.nodesource.com/node_14.x focal main
deb-src https://deb.nodesource.com/node_14.x focal main
ubuntu@batcomputer$ sudo apt -y install nodejs

• Run the React.js web application on The Batcomputer

ubuntu@batcomputer$ cd ~/opt/alfred/ui/react
ubuntu@batcomputer$ npm i --save
ubuntu@batcomputer$ npm start
Compiled successfully!

You can now view batcomputer in the browser.

  Local:            http://localhost:3000
  On Your Network:  http://batcomputer:3000

Note that the development build is not optimized.
To create a production build, use npm run build.

• To control the robot from the React.js web application, open a browser on The Batcomputer and navigate to http://batcomputer:3000.

You should be able to drive and rotate the robot with this web application.

To control the robot with an iOS application, open the Xcode project on a Mac and simply run it in the simulator or on a device on the same local network.