Contains all ROS nodes for X-17 that run on Raspberry Pi 4
The launch file can be found in the rov_launch folder. The launch file is called core_launch.yaml
The launch file can be run using the following command:
ros2 launch rov_launch core_launch.yaml
If you need to build and source the workspace, you can use the following commands:
colcon build
source install/setup.bash
On the device to run X17-Core (typically the Raspberry Pi), create a directory called ros2_ws, within this work space create another directory called src. Inside the src directory, clone this repository. While inside the ros2_ws directory, run the command source /opt/ros/humble/setup.bash. ROS2 (Humble) needs to be installed for this work; the installation commands are found in https://docs.ros.org/en/humble/Installation.html. The source command will "initialize" ROS2 on the device. From there, run colcon build which will create the executables that will run. After that completes, run the command . install/setup.bash. To run specific files, do the command ros2 run _project-name_ _file-name_. To have multiple files running, you can open multiple terminals and run that command for each file.
To publish to a topic, use the command ros2 topic pub /final_thrust shared_msgs/FinalThrustMsg "thrusters: [127,127,127,127,127,127,127,127]"
X17-Core uses UART for its communication protocol between the Raspberry Pi and the STMs on the electrical boards. There are four different message types.
- Thrust data message
- ESC data message
- Power data message
- Tools data message
The UART protocol used will not have parity bits enabled. It will be running at a baud rate of 9600. Each message has a device ID which is the ID of the destination of the message. Each message will also have CRC which uses the CRC-32 MPEG2 polynomial, however, we only save the last 8-bits of the 32-bit CRC value. There are two UART lines, one for the tools, and one for the thrusters/ESC/power bricks. The acknowledge will be of the same structure as the data messages.