crazyflie_ros2_experimental

NOTE: This project has come to an end! Currently, efforts are in place to translate some of these nodes or the principle of them to the crazyswarm2 project, which will be eventually be published to be the official Crazyflie2 ROS package.

This is my Bitcraze Summer project of 2022! Purpose: To use ROS2 to implement SLAM and navigation with the Crazyflie , Flow deck and Multiranger, on both the real drone and simulation.

This is very much in progress, but I'm excited to work on this and very confident that this will work at the end. Also, this is a good opportunity for me to show an ROS2 implementation of a new platform from scratch, so why not start with the Crazyflie 🙂

See this Blogpost explaining the bulk of the current process.

Content

• Goal Project
• Current Status
• How to run
• Planning
• Develop

Goal Project

Pretty much this:

... but with a map generated while doing it, and using navigate with it. And... being able to do this on a real Crazyflie too! How hard can it be? 😃

But no seriously, I hope to at least get the SLAM mapping toolbox to work by the end of the summer 2022, and from there it is an ongoing project that can pretty much go on. If we got something working and stable, it could be part of an official Crazyflie_ROS2 package that we release in the future. Also, it would be great to show these with existing packages like SLAM_toolbox or NAV2.

For now this project is on my personal GitHub repo for now and once there is something solid working it will be probably transferred to the Bitcraze GitHub organization.

Current Status

Currently, the simple_mapper node works on a real crazyflie what is controllable through twist messages.

Simple mapper on Crazyflie

NAV2 with Simple Mapper

Single room with added obstacle

Single room with corridor

As you can see this is quite difficult to achieve! That is why we need to get the SLAM toolbox tuned and ready.

SLAM toolbox with NAV2 on simulated Crazyflie

This a video of the SLAM toolbox in simulation without ray fitting on, together with the nav toolbox. In order to get rayscanning to work we need more tuning.

Explanation per package

• crazyflie_ros2: The Crazyflie package that has contact with the Crazyflie directly and publishes the transforms
• crazyflie_ros2_description: The package that handles the RViz screen and also includes meshes if necessary
• crazyflie_ros2_simulation: A webots simulator world and ROS node controller (based on the experimental bitcraze simulation repo)
• crazyflie_ros2_slam: Using an existing SLAM toolbox to create a map
• crazyflie_ros2_simple_mapper: An own made simple mapper functionality for multirangers and flowdeck-based odometry
• crazyflie_ros2_navigation: Using the NAV2 bringup package with changed parameters
• crazyflie_ros2_scan: Node that turns multiranger into 360 scan (not finished, check issues)
• crazyflie_ros2_interfaces: Containing actions or messages specific to crazyflie ros2
• ... more to come (check planning)

How to run

ROS 2 version: Galactic

First install all dependencies by entering the repository root and run:

Before running the make command, please make sure, you have ROS 2 sourced with source /opt/ros/galactic/local_setup.bash

make all

Here you can read more about other Makefile targets.

Wait until everything is build and setup for you. And this point you are ready to proceed futher.

Then, go to your development workspace and run:

source install/setup.bash

Before running the package following tasks have to be done:

1. Setup rules for accessing the Crazyradio
2. Export your radio address as CFLIB_URI variable, for example export CFLIB_URI=radio://0/80/2M/E7E7E7E7E7

RViz 2 + Control

Start RViz 2 by typing

rviz2

and select the map visualization

You can control both the simulated and real crazyflie with twist messages:

ros2 run teleop_twist_keyboard teleop_twist_keyboard

Real Crazyflie

You will need an STEM ranging bundle for this.

All these nodes will make the Crazyflie take off right away to height of 0.5 meters

Simple mapper

ros2 launch crazyflie_ros2_simple_mapper simple_mapper_real_launch.py

SlamToolbox

Not working ideally yet!

ros2 launch crazyflie_ros2_slam slam_toolbox_real_launch.py

NAV2

For now only with simple mapper

ros2 launch crazyflie_ros2_navigation navigation_real_launch.py

Simulated Crazyflie

First install webots 2022a

This crazyflie webots controller uses the python bindings of the crazyflie firmware. Replace this line in crazyflie_ros2_simulation/crazyflie_ros2_simulation/crazyflie_webots_driver.py with the location of your crazyflie-firmware repo and do make binding_pythons:

sys.path.append('/home/knmcguire/Development/bitcraze/c/crazyflie-firmware')
import cffirmware

Simple mapper

ros2 launch crazyflie_ros2_simple_mapper simple_mapper_simulation_launch.py

SlamToolbox

Not working ideally yet!

ros2 launch crazyflie_ros2_slam slam_toolbox_simulation_launch.py

NAV2

With the SLAM toolbox with use_scan_matching on False

ros2 launch crazyflie_ros2_navigation navigation_simulation_launch.py

Planning

• Make a ROS2 publisher node for crazyflie (with cflib) to publish pose and transform
• Make crazyflie description package with RViz 2 visualization file and Crazyflie robot mesh
• Make crazyflie_ros2_slam node starting with the slam_toolbox's parameters
• Connect crazyflie_ros node to the crazyflie_ros2_node and generate a map with RViz 2 (needs tuning in simulation first
• Make crazyflie_ros2_simulation package with Webots
• Turn the multiranger pointcloud example into a ROS 2 node equivalent (crazyflie_ros2_simple_map)
• Have simulator run in simple mapping node
• Have real crazyflie fly in simple mapper node
• Connect webots simulation to the SLAM toolbox
• In Simulation tune the SLAM toolbox to work for 4 laser rangers (if possible)
• If tunable, try out on real crazyflie + multiranger -> doesn't work as I hoped.
• Make node that makes a 360 scan message of a rotating crazyflie
• Connect 360 scan with SLAM toolbox and see if it improves things
• Try NAV2 on simple mapper node
• Make 3d mapping visualization
• Implement wall following?
• If available, use python bindings of the Crazyflie's onboard EKF
• Try out new multi-zone multiranger deck

Issues to solve

• crazyflie_ros needs to publish odometry messages properly
• replace manual crazyflie robot after Webot's release to 2022b
• Action can not handle multiple threads so topic handling is not great. Should fix with this: https://answers.ros.org/question/356434/ros-2-actionserver-callback-causes-subscriber-to-stop-receiving/
• Simulation underestimates position crazyflie which results in a weird map building in simple mapper (didn't have this 2 weeks ago??)
• THe yaw control on the webots driver is much slower than with the crazyflie driver. Even though it is the same code.

Some handy things for me to remember:

For installing cflib as an external dependency

sudo mkdir -p /usr/local/share/ros && sudo cp cflib-python.yaml /usr/local/share/ros

echo "yaml file:///usr/local/share/ros/cflib-python.yaml" | sudo tee -a /etc/ros/rosdep/sources.list.d/20-default.list
rosdep update

rosdep install --from-paths src --ignore-src -r -y

WSL use https://github.com/dorssel/usbipd-win/wiki/WSL-support

Run TF tree viewer

ros2 run rqt_tf_tree rqt_tf_tree --force-discover

Problem gui wsl microsoft/wslg#554

LIBGL_ALWAYS_SOFTWARE=true

ros2 launch slam_toolbox online_async_launch.py

Develop

Take a look at the develop documentation about the tool helping with formatting and code style recommendations.