The Create® 3 exposes ROS 2 topics, actions, and services over both WiFi and the USB-C cable powering the Raspberry Pi. This gives users access to the battery state, sensor data, docking actions, and more. While the Create® 3 can be used with just the USB-C interface, when used with the simple discovery networking configuration, the Create® 3 will require a WiFi connection in order to view the robot model on Rviz or run software such as SLAM or Nav2 from a user computer.
The Raspberry Pi 4B on both the TurtleBot 4 and TurtleBot 4 Lite comes preinstalled with Ubuntu 22.04 Server, ROS 2 Humble, and TurtleBot 4 software. The latest TurtleBot 4 images can be found here. The purpose of the Raspberry Pi 4B is to run the TurtleBot 4 ROS nodes, run sensor ROS nodes, use Bluetooth to connect to the TurtleBot 4 controller, access GPIO, and more.
The user's PC is used to configure the robot, visualise sensor data, run the TurtleBot 4 simulation, and run additional software. The PC is required to run Ubuntu 20.04 with ROS 2 Galactic installed, Ubuntu 22.04 with Ros 2 Humble installed or to use a Virtual Machine running Ubuntu 20.04 or 22.04. This version must match the version running on the robot. A typical laptop or desktop will offer significantly higher processing performance than the Raspberry Pi can, so running applications such as Nav2 or SLAM on the PC will provide significant performance improvements.