ASTRA Rover ROS2 Packages

Includes all main ROS2 packages for the rover. These are centrally located for modular rover operation.

You will use these packages to launch all rover-side ROS2 nodes.

Table of Contents

• Software Prerequisites
  • Nix
  • ROS2 Humble + rosdep
• Running
  • Testing Serial
  • Connecting the GuliKit Controller
• Common Problems/Toubleshooting
• Packages
• Maintainers

Software Prerequisites

You need either ROS2 Humble with rosdep or Nix installed. We recommend using Nix.

Nix

With Nix, all you have to do is enter the development shell:

$ cd path/to/rover-ros2
$ nix develop

ROS2 Humble + rosdep

With ROS2 Humble, start by using rosdep to install dependencies:

  # Setup rosdep
$ sudo rosdep init  # only run if you haven't already
$ rosdep update
  # Install dependencies
$ cd path/to/rover-ros2
$ rosdep install --from-paths src -y --ignore-src

Running

$ colcon build
$ source install/setup.bash
  # main launch files:
$ ros2 launch anchor_pkg rover.launch.py  # Must be run on a computer connected to a MCU on the rover.
$ ros2 run headless_pkg headless_full  # Optionally run in a separate shell on the same or different computer.

Testing Serial

You can fake the presence of a Serial device (i.e., MCU) by using the following command:

$ socat -dd -v pty,rawer,crnl,link=/tmp/ttyACM9 pty,rawer,crnl,link=/tmp/ttyOUT

When you go to run anchor, use the PORT_OVERRIDE environment variable to point it to the fake serial port, like so:

$ PORT_OVERRIDE=/tmp/ttyACM9 ros2 launch anchor_pkg rover.launch.py

Connecting the GuliKit Controller

These instructions apply to the black XBox-style GuliKit controller, primarily used for controlling Arm through Basestation.

• Connect the controller to your PC with a USB-C cable
• Select the "X-Input" control mode (Windows logo) on the controller.
  • Hold the button next to the symbols (windows, android, switch, etc...)
  • You'll need to release the button and press down again to cycle to the next mode

Common Problems/Troubleshooting

Q: When I try to launch the nodes, I receive a package '' not found error.

A: Make sure you have sourced the workspace in the current shell:

$ source install/setup.bash  # or setup.zsh if using ZSH

Q: When I try to launch the nodes, I receive several FileNotFoundError: [Errno 2] errors.

A: Sometimes the install files get messed up by running colcon build in different shells or updating packages. Try running the following commands to clean up your local build files:

$ rm -rf build/ install/
$ colcon build

Q: When I run colcon build after the above suggestion, I receive several of the following errors:

[0.557s] WARNING:colcon.colcon_ros.prefix_path.ament:The path '' in the environment variable AMENT_PREFIX_PATH doesn't exist

A: Don't worry about it. If you had the workspace sourced, ROS2 will complain about the workspace install files not existing anymore after you deleted them. They will be re-created by colcon build, after which you can run source install/setup.bash to source the new install files.

Q: When I try to launch Anchor, I receive the following errors:

[anchor-5] [INFO] [1762239452.937881841] [anchor]: Unable to find MCU...
...
[ERROR] [anchor-5]: process has died [pid 101820, exit code 1, cmd '.../rover-ros2/install/anchor_pkg/lib/anchor_pkg/anchor --ros-args -r __node:=anchor --params-file /tmp/launch_params_nmv6tpw4'].
[INFO] [launch]: process[anchor-5] was required: shutting down launched system
[INFO] [bio-4]: sending signal 'SIGINT' to process[bio-4]
[INFO] [ptz-3]: sending signal 'SIGINT' to process[ptz-3]
[INFO] [core-2]: sending signal 'SIGINT' to process[core-2]
[INFO] [arm-1]: sending signal 'SIGINT' to process[arm-1]
...

A: To find a microcontroller to talk to, Anchor sends a ping to every Serial port on your computer. If it does not receive a 'pong' in less than one second, then it aborts. There are a few possible fixes:

• Keep trying to run it until it works
• Run lsusb to see if the microcontroller is detected by your computer.
• Run ls /dev/tty*0 to see if there is a valid Serial port enumerated for the microcontroller.
• Check if you are in the dialout group (or whatever group shows up by running ls -l /dev/tty*).

Packages

• anchor_pkg - Handles Serial communication between the various other packages here and the microcontroller.
• arm_pkg - Relays controls and sensor data for the arm (socket and digit) between anchor and basestation/headless.
• astra_descriptions - Submodule with URDF-related packages.
• bio_pkg - Like arm_pkg, but for CITADEL and FAERIE
• core_pkg - Like arm_pkg, but for Core
• headless_pkg - Simple, non-graphical controller node to work in place of basestation when controlling the rover by itself. This is autostarted with anchor to allow for setup-less control of the rover.
• latency_tester - A temporary node to test comms latency over ROS2, Serial, and CAN.
• ros2_interfaces_pkg - Contains custom message types for communication between basestation and the rover over ROS2. (being renamed to astra_msgs).
• servo_arm_twist_pkg - A temporary node to translate controller state from ros2_joy to Twist messages to control the Arm via IK.

Maintainers

Name	Email	Discord
David Sharpe	ds0196@uah.edu	@ddavdd
Riley McLain	rjm0037@uah.edu	@ryleu