System

Proper networking setup is crucial in setting up the ROS 2 middleware and to ensure other onboard computers communicate reliably.

Username

The username indicates the username that will be used to run all ROS nodes. If this username needs to be changed then the robot services must be reinstalled as directed in the software installation instructions.

Hosts

The hosts section serves as a way to match hostnames to IP addresses. By default, Clearpath robots use the serial number as the hostname and have a default IP of 192.168.131.1. This section must define ip addresses for all hostnames that appear in the remainder of the robot.yaml file.

For example:

  hosts:
    - hostname: cpr-a200-0000 # The robot computer
      ip: 192.168.131.1
    - hostname: offboard-computer
      ip: 192.168.131.5

ROS 2 Environment

The ros2 section is necessary to set up the ROS 2 networking.

Key	Value / Datatype	Description
namespace	string	Specified will be appended as a prefix to all sensor topics to prevent topics from being overloaded when multiple robots are on the same network and domain ID.
domain_id	integer	Specifies the ROS 2 domain ID to use.
middleware	See Below	Specifies the ROS 2 middleware settings.
workspaces	list	Indicates a list of custom ROS 2 workspaces that need to be sourced by specifying the path to the setup.bash or set to [] to leave it blank

For example:

ros2:
  username: administrator
  namespace: a200_0000
  domain_id: 0
  middleware: # This section is described further below
    implementation: rmw_fastrtps_cpp
  workspaces:
    - /home/administrator/colcon_ws/install/setup.bash # Path to the custom workspace

Middleware

The middleware section defines the which RMW Implementation to use and any related settings. To choose which implementation and discovery method is right for your project see networking.

Key	Value / Datatype	Description
implementation	rmw_fastrtps_cpp	Declares the RMW Implementation to use. Currently only supports rmw_fastrtps_cpp.
discovery	simple or server	Select simple for simple discovery and server for discovery server. (Defaults to simple)
profile	string	Advanced feature, allows an optional custom XML profile to be provided - RMW Implementation / vendor specific.
servers	list	Provides a list of all discovery servers in the system and whether or not the robot should connect to them.

For example:

middleware:
  implementation: rmw_fastrtps_cpp
  discovery: simple
  profile: path/to/profile.xml
  servers: # This section is described further below
    - hostname: cpr-a200-0000

Servers

This section is only used with eProsima Fast DDS Discovery Server (implementation: rmw_fastrtps_cpp and discovery: server).

note

This section must define every single discovery server in the system. This must include not only every discovery server that this robot is connecting to but also every discovery server that the offboard computer will connect to in the system.

Each server can be defined with a number of different parameters:

Key	Value / Datatype	Description
hostname	string	The hostname of the computer that is hosting the server (must be in the hosts list).
port	integer	The port at which to connect to the server (default is 11811).
enabled	True or False	This indicates whether or not the robot should connect to this server and, if the hostname matches the computer's own hostname, whether or not to launch the server (default is True).

For example:

servers:
  - hostname: cpr-a200-0000
    port: 11811
    enabled: True

Sample

Sample A200 System Section

In our sample, we have a Husky A200 platform whose primary computer has the hostname: cpr-a200-0000 and IP: 192.168.131.1.

By default, all Clearpath robots use the username administrator and the robot's namespace matches the serial_number.

system:
  username: administrator
  hosts:
    - hostname: cpr-a200-0000
      ip: 192.168.131.1
  ros2:
    namespace: a200_0000
    domain_id: 0
    middleware:
      implementation: rmw_fastrtps_cpp
      discovery: simple
    workspaces: []

At this point, with just the serial_number and system defined, our robot is just the standard Husky A200 platform, and looks like this:

Default Husky A200