FSimROS

A package of FlightSims.jl family for ROS2.

Note that ./src/fsim_interfaces is a ROS2 package for providing interfaces of FlightSims.jl family.

Notes

• ROS2 should be installed.
• Put ./src/fsim_interfaces in dev_ws/src (ROS2 convention; don't be confused with ./src) where your ROS2 workspace is, namely, dev_ws.
• (Startup latency) Using PackageCompiler.jl might be a good solution to this issue. For this, see test/precompile.jl (some modification may be required to execute the code). However, this remedy did not solve this issue completely. Instead, simply adding auxiliary lines as the initialisation of each node works well. Note that the main bottleneck was simulator update, e.g., step_until! exported from FlightSims.jl.

Examples

Minimal publisher-subscriber example

See ./test/pubsub.

Simulation and visualisation with data communication via ROS2

See ./test/PILS for a circular trajectory tracking of a hexacopter with a backstepping position controller (500 Hz communication). Use a docker image ihany/ros:foxy-fsimros, or use the ./Dockerfile with command docker buildx (supported platforms: linux/amd64, linux/arm64).

The following instruction assumes that a related docker container is running; e.g.,

docker run --name ros --network host --rm -it -e display=$display -v /tmp/.x11-unix:/tmp.x11-unix ihany/ros:foxy-fsimros

• -e display=$display -v /tmp/.x11-unix:/tmp.x11-unix: for visualisation
• --network host: (optional) to communicate with other machines in the same network

Instruction:

• (Note) The Julia packages in docker image may be not up-to-date. You may have to the latest commit of branch master, for example, git fetch; git checkout master; git rebase origin/master at ~/.julia/dev/FSimROS.
• Source ./dev_ws in the docker image by . install/setup.zsh.
  • (Recommended) Enter a tmux session by ts your_session_name.
• Move to: cd ~/.julia/dev/FSimROS.
• On a terminal, run as julia test/PILS/viz.jl.
• On a new terminal, run as julia test/PILS/simulator.jl.
• On a new terminal, run as julia test/PILS/controller.jl.
• Wait other nodes. Then, on another new terminal, run as julia test/PILS/timer.jl See the result (video speed adjusted):

MAVSDK-Python + ROS2

See test/mavsdk-ros2. Currently, Python code is implemented (not Julia code). To run the code in a docker container, one should connect the host's peripheral (device) with the option --device such as --device=/dev/ttyACM0.

docker run --name ros --network host --rm -it -e display=$display -v /tmp/.x11-unix:/tmp.x11-unix --device=/dev/ttyACM0 ihany/ros:foxy-fsimros

To-do

• sync issues (maybe?) for divergence of controller (which requires integration)
  • Perhaps, we need a central node for topic time and each simulation and controller receives the time to propagate own dynamical system and adaptive control system.
• Update the docker image's building process to include FSimROS.jl
• Reduce first-execution delay of Julia code
• Make the docker image stable, i.e., consistent version control of Julia packages
• Add an example of processor-in-the-loop simulation (PILS) with Pixhawk.

Notes

• Tested with only few test environments, e.g., Ubuntu 20.04, ROS2 foxy, docker.