Technical requirements
In the https://github.com/ros-mobile-robots organization on GitHub
are the required ROS packages to set up a differential drive robot.
One of the main software repositories is https://github.com/ros-mobile-robots/diffbot.
It includes packages for simulation and the configurations and software to operate a real
robot and interact with it from a development PC. For the hardware, you can build your
own two- or four-wheeled differential drive robot similar to the one present in the
diffbot_description
package or 3D print a more stable Remo robot with the stl files in
https://github.com/ros-mobile-robots/remo_description.
The next two sections describe the technical requirements for the software and hardware.
Info
This technical requirements page is here to give you an overview of what is required to get your robot up and running. You can already follow the steps in practice but they will be also mentioned in later sections (in more detail) when they are really needed.
Software requirements
The following sections give an overview about which software will be used:
- Operating Systems
- Git
- Remote Control
- Hardware Interface
- Source Dependencies
- Binary Dependencies
- Build ROS Workspace
More detailed software setup instructions are found in the chapter about Processing Units.
Operating System
For the development PC, you should have ROS Noetic installed on Ubuntu 20.04 or using Windows Subsystem for Linux (WSL) 2 running on Windows 11.
Note
Windows 11 is required for GUI features, such as Gazebo and RViz. WSL 2 on Windows 10 only provides command line support, although you can install an X11 server, such as VcXsrv, explained here.
On the Single Board Computer (SBC) (e.g. Raspberry Pi 4 B) that is mounted on Remo, we use Ubuntu Mate 20.04 for arm64 architecture.
Git
As the software is hosted on GitHub which uses git as a version control system it needs to be present in your used operating system.
On Ubuntu this is usually the case, which you can check with:
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On Windows you need to install Git using a package manager such as chocolatey or downloading it from https://git-scm.com/downloads.
To clone large stl files from the Git repository we use git-lfs. On both Ubuntu flavors it needs to be installed with the following terminal command:
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Remote Control
On both the development PC and the SBC of the robot, you need a connection to the same local network and to enable the ssh protocol, to connect from the development PC (client) to the robot, which is running an open-ssh server. Install it on Ubuntu Mate 20.04 with the following:
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Hardware Interface
Another interface setup that is needed to work with the microcontroller, is to add your
user to the dialout
group on both machines, the SBC and the development PC. This can
be done with the following command, followed by a system reboot:
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Source Dependencies
When you clone the diffbot repository in a new catkin workspace, you will find two
YAML files, diffbot_dev.repos
and remo_robot.repos
, that list required source
dependencies together with their version control type, the repository address, and a
relative path where these dependencies are cloned. remo_robot.repos
is here to clone
source dependencies on the real robot.
To make use of such YAML files and clone the listed dependencies, we use the commands
from vcstool
, which replaces
wstool
:
-
Install vcstool using the command:
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sudo apt install python3-vcstool
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In a new catkin workspace, clone the diffbot repository inside the src folder:
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ros_ws/src$ git clone https://github.com/ros-mobile-robots/diffbot.git
for a specific tag (e.g. 1.0.0) you can use the following command:
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ros_ws/src$ git clone --depth 1 --branch 1.0.0 https://github.com/ros-mobile-robots/diffbot.git
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Make sure to execute the
vcs import
command from the root of the catkin workspace and pipe in thediffbot_dev.repos
orremo_robot.repos
YAML file, depending on where you execute the command, either the development PC or the SBC of Remo to clone the listed dependencies:1
vcs import < src/diffbot/diffbot_dev.repos
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Execute the next command on the SBC of the robot:
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vcs import < src/diffbot/remo_robot.repos
Binary Dependencies
After obtaining the source dependencies with vcstool
, we can compile the workspace.
To successfully compile the packages of the repository, binary dependencies must be
installed. As the required dependencies are specified in each ROS package's package.xml
,
the rosdep command can install the required ROS packages from the Ubuntu repositories:
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Build ROS Workspace
Finally, the workspaces on the development machine and the SBC of the robot need to
be built, either using catkin_make
or catkin tools. catkin_make
comes pre-installed with ROS.
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Hardware requirements
The repository at https://github.com/ros-mobile-robots/remo_description contains the
robot description of Remo. Remo is a modular mobile robot platform, which is based on
NVIDIA's JetBot. The currently available parts can be 3D printed using the provided
stl files in the remo_description
repository.
To do this, you either need a 3D printer with a recommended build volume of 15x15x15 cm or to use
a local or online 3D print service. Further details are found in hardware setup.
On the following components page you find a bill of materials and more details about each part.