simulation

Today we have a guest blogpost by Thomas Izycki (Technische Hochschule Augsburg) and Klaus Kefferpütz (Ingolstadt Technical University of Applied Sciences, former Augsburg Technical University of Applied Sciences) talking about implementing Software-in -the-Loop for swarm simulation of the Crazyflie.

When our cooperative control lab at the Technical University of Applied Sciences Augsburg was founded a few years ago, our goal was to develop distributed algorithms for teams of UAVs. We quickly decided to use Crazyflies with the algorithms directly implemented in the firmware, thus having a platform for a truly decentralized system. Our ongoing projects focus on cooperative path planning, navigation, and communication.

Since working with several drones at once, which have to communicate and coordinate with each other, can quickly become confusing and very time-consuming, a simulation was needed. It should preferably offer the possibility to integrate the firmware directly in the simulation environment and ideally also offer an interface to the crazyflie python API. With the relocation of our laboratory from Augsburg to the Technical University of Applied Sciences Ingolstadt, which however does not yet have a permanently established flying space, the need for a simulation environment was further increased in order to be less dependent on hardware accessibility. A look at the community and the available simulations quickly led us to the sim_cf flight simulator for the Crazyflie. A fantastic project supporting the use of the actual Crazyflie firmware in software-in-the-loop (SITL) mode and even in hardware-in-the-loop (HITL) mode on a real Crazyflie using the FreeRTOS Linux Port together with ROS and Gazebo. Unfortunately, the project has not been maintained for several years and also had no integration with the Crazyflie Python API. After a short chat with Franck Djeumou and his agreement to use the code of the original sim_cf simulation, the project was ready for an upgrade.

sim_cf2 Flight Simulator

With support for ROS coming to an end we decided to migrate the project to ROS2 and additionally support the current version of the Crazyflie firmware, which at this time is release version 2023.11. With the addition of a driver to connect the cflib to the SITL process, the same python cflib-based scripts can now be used with real Crazyflies and for use in the simulation environment. Only the corresponding driver needs to be loaded during initialization. Overall, the focus of the sim_cf2 simulation is now on using the Crazyflie python API instead of commanding the Crazyflies via ROS.

As for the Crazyflie firmware the whole build process has been fully integrated into the firmware’s KBuild build system. This also allows the use of the same code base for simulation and execution on the real Crazyflie. Depending on the configuration, the firmware is compiled for the STM32F on the Crazyflie or the host system running the SITL.

Components of the sim_cf2 Flight Simulator

To run the simulation, the three modules must therefore be started separately. Gazebo is started using the main launch file. The number and initial pose of the simulated Crazyflies is also defined in this file. Once the firmware for the host system has been built, the desired number of SITL instances can be started using the attached script. Finally, a cflib-based script, the Crazyflie client or the multi-agent client presented below is started. With no radio dongles attached to the computer, the simulation driver is initialized automatically and a connection to the simulated Crazyflie can be established.

There are still a few open issues, including the absence of implemented decks for positioning, such as LPS and Lighthouse. Currently, the absolute position is sent from Gazebo to the SITL instance and fused in the estimator. Moreover, Gazebo requires quite a lot of computing power. We were able to run a maximum of four Crazyflies simultaneously on a relatively old laptop. However, a modern desktop CPU with multiple cores allows for simulating a significantly larger number of Crazyflies.

Multi-Agent Client

Independent of the simulation we designed a GUI for controlling and monitoring our multi-agent teams. It currently supports up to eight Crazyflies but could be upgraded for bigger teams in the future. So far it has been enough for our requirements.

Multi-Agent Client with six connected Crazyflies

A central feature is the interactive map, which makes up about half of the gui. This is a 2D representation of the flight area with a coordinate system drawn in. Connected Crazyflies are displayed as small circles on the map and a new target position can be assigned by clicking on the map after they have been selected by their corresponding button. If required, obstacles or paths to be flown can also be drawn into the map.

Pseudo-decentralized communication

An important aspect of a truly decentralized system is peer to peer communication. It allows information to be exchanged directly between agents and ideally takes place without a central entity. Currently peer to peer communication is not available in the Crazyflie ecosystem, but is in development.

For this reason, we have implemented a workaround in our client, enabling a pseudo-decentralized communication system. This involves adding an additional layer to the Crazy RealTime Protocol (CRTP), which we named the Multi-Agent Communication Protocol (MACP). It consists of an additional packet header made of the destination ID, source ID and a port as endpoint identifier. Every ID is unique and directly derived from the Crazyflie’s address.

These MACP packets are sent via the unused CRTP port 0x9. The packet routing mechanism implemented in the client forwards the packets to their destination. It is also possible to send packets as a broadcast or to address the client directly.

On the firmware side, we have added a corresponding interface to simplify the sending and receiving of macp packets. It is analogous to the CRTP implementation and allows the registration of callback functions or queues for incoming packets on corresponding ports. It can be activated via KBuild.

At least for use in the laboratory and the development of distributed algorithms, this method has proven its worth for us.

Project

We hope that the sim_cf2 simulation can also be useful to others. The complete source code is available on GitHub. Further information concerning installation and configuration can be found in the readme files in the respective repositories.

We would also like to point out that other simulations have been created that are based on sim_cf and therefore offer similar functionality. One of these projects is CrazySim, also available on GitHub. Moreover, there are ongoing efforts to officially integrate such a software-in-the-loop simulation into the Crazyflie firmware and ecosystem.

sim_cf2:

https://github.com/CrazyflieTHI/sim_cf2

Multi-Agent Client:

https://github.com/CrazyflieTHI/crazyflie-client-multi-agent-thi

Show-and-tell post of CrazySim:

https://github.com/orgs/bitcraze/discussions/995

For the original sim_cf Flight Simulator for the Crazyflie visit:

https://github.com/wuwushrek/sim_cf

It seems that many of you are very interested in simulation. We might have gotten the hint when we noticed that our July’s development meeting had our best attendance so far! Therefore, we will be planning a new developer meeting to discuss the upcoming plans for supporting simulation for the Crazyflie.

Getting Started with Simulation tutorial

Perhaps you are not aware, but there is actually a Getting Started tutorial for simulation that has been available for a little over 2 months now. Unfortunately, circumstances prevented us from writing a blog post about it, but we’ve noticed that not all of you are aware of it yet!

The getting-started tutorial demonstrates how to set up the Webots simulator, which already includes Crazyflie models and some cool examples:

  • An example that you can control the Crazyflie with the keyboard
  • An example that the Crazyflie does wall following autonomously

The latter is based on the example app layer for wall-following in the crazyflie-firmware repository. Starting this year, there’s also a Python library equivalent available.

The tutorial concludes with instructions on how to edit these controllers. Alternatively, you can choose to run the files directly from the crazyflie-simulation repository. After completing the tutorial, you can explore the simulation repository documentation for more information and to access additional examples.

Upcoming plans

With so many plans and so little time! This is a common phrase at Bitcraze, and it’s a symptom of being an overly ambitious, but too small, team. By the way, we are still looking for more people :). Nonetheless, we have big plans to take our Crazyflie simulation to the next level:

  • ROS 2 Crazyflie model for Webots: The Crazyflie has been a part of the Webots standard robots for 2 years now, but we still need to implement the Crazyflie into the Webots ROS 2 repository.
  • Better (new) Gazebo support: Currently, we only have a very simple example for Gazebo, which is limited to motors with no control input. Working with the C++ API can be a bit challenging, so it might be worth considering the use of ROS 2 in the loop here. Let’s see what comes out of it.
  • Integration into Crazyswarm2: Once the Webots ROS2 node has been released, integrating the Crazyflie simulation into Crazyswarm2 will become more straightforward.
  • Improvement to the Python bindings: We’ve had Python bindings for controllers and the high-level commander for a while. Recently, we also added Python bindings for the estimator (currently for loco positioning only). However, there are still some issues to address with the Python bindings for the controllers due to timing issues with the simulators.
  • Linking with our CFLIB: Currently, both Webots and the Crazyflie Python library use entirely different APIs. This means that these scripts are not compatible and you’ll need to be creative not to reuse new code. However, wouldn’t it be nice to use a python example from the python library with a --sim and that it would actually control the Crazyflie in the simulator instead?

Of course, there are probably more improvements that we haven’t thought of yet, but that’s why we have developer meetings!

Come and join us at the Developer meeting.

We will be hosting another developer meeting on November 1st at 15:00 Central European Time (accounting for the time-shift from summer to autumn). You can find details on how to join in the discussion thread here.

Just for your information, I (Kimberly) am the main driving force behind our simulation efforts. However, I’m currently on partial sick leave and will soon be on full leave for a while. I kindly ask for your patience with the pace of ongoing developments. Remember, it’s an open-source project, so if you’d like to contribute and help out, we would greatly appreciate it :)

As of this year around March/April we started with both Bitcraze developer meetings and Aerial-ROS meetings (the latter in collaboration with Dronecode Foundation). Now that summer is around and our office is a bit empty, we had a bit of a summer break, however we will start the meetings back up again soon! The next ROS-aerial meeting will be on the 16th of August and we will also have a Bitcraze developer meeting planned on the Wednesday the 6th of September (keep an eye on our announcements in discussions). In this blogpost we like to take the opportunity to show an overview of the meetings we had so far.

Aerial ROS meetings

In March we started a [ROS community working group] for aerial Vehicles together with our friends at Dronecode foundation, aka Aerial-ROS! We have biweekly meetings with some standard discussion meetings (with a topic) and with an invited guest presentation.

Here are the discussion topic meetings we had:

And we had several guest speakers as well! Like Miguel Fernandez-Cortizas from CAR-UPM talking about Aerostack2:

ROS-aerial Meeting guest presentation about Aerostack2

Then we had a guest presentation from Gerald Peklar from NXP talking about the Drones4Bats project:

ROS-aerial Meeting guest presentation about Drones4Bats

And the last before the summer was from Alejandro Hernández Cordero (Open Robotics Consultant) about the ROS2 Project Vehicle Gateway.

ROS-aerial Meeting guest presentation about Vehicle Gateway

The next meeting for ROS-aerial is planned on the 16th of August. Keep an eye on the ROS discourse forum.

Bitcraze Developer Meetings

We already had a couple of developer meetings before but we started recording them since April. The first recorded one was about the loco positioning system. Here first we gave a presentation about the system itself, with the latest developments cooking in our pot and time for questions afterwards.

Dev meeting about Loco positioning.

Then we had a meeting about the development of safety features in the Crazyflie in light of the Bolt developments:

Bitcraze Dev meeting about Safety features.

Then we had a meeting where Kristoffer highlighted the autonomous swarm demo we showed at ICRA 2023.

Bitcraze dev meeting about the autonomous swarm demo

And the last before the summer holiday, we had a meeting where Kimberly explained about the Crazyflie simulationmodel intergrated into Webots

Bitcraze Dev meeting about Simulation

We are still planning to have developer meeting every first wednesday of the month starting with September 6th (keep an eye on our announcements in discussions).

EPFL 101 Crazyflie presentation

Oh yeah, by the way, we also were invited by the EPFL-lis lab to give another Crazyflie 101 presentation in Lausanne last April! We made a prerecording of it so you can check it out right here:

EPFL LIS crazyflie 101 presentation.

See you all after summer!

Announcement: We will have a townhall meeting this Wednesday (7th of December) about Crazyradio 2.0 and the ideas about the new com-stack at 15:00 (3 pm) CET. Please follow the discussion here for more info.

As you have been very much aware of already if you have been reading the blog occasionally is that we went to Japan with the entire company to be at the International Conference on Intelligent Robots and Systems (IROS) in Kyoto, Japan. Besides eating great food, singing karaoke, and herding our fully onboard autonomous swarm at our stand, we also had some time to check out what kind of work was done with the Crazyflie in the proceeding papers and talks!

So just some generic statistics first:

  • IROS had 1716 papers accepted
  • We found 14 Crazyflie papers/posters and 2 workshop papers
  • The three biggest topics we found the papers in were: SLAM, Multi-robot systems and Navigation & Motion planning, SLAM

At ICRA this year, we noticed that the Crazyflie/bolt were used to make unconventional platforms, like a mono-copter or transforming the Crazyflie to a Pogo stick. It was interesting to see that now at IROS, the focus seemed to be more on navigation, localization and even SLAM… also with unconventional sensors!

Navigation and SLAM with the Crazyflie

In the summer I (Kim) worked on a summer project with using ROS2 to try SLAM with the standard packages with the Flow deck and Multi-ranger. This was also to present the work at ROScon before that with the Crazyswarm2 project, the Crazyflie can be used as an actual robotic platform too! I’m glad that some researchers already figured this one out already, as there were quite some papers on SLAM! [6] and [12] made use of the flow & multi-ranger but made their own custom algorithms to do SLAM and mapping that was more tailored to the task than the standard SLAM packages out there meant for 360 degree lidars.

Very interestingly, there were several papers that uses unconventional sensors for this as well. [5] used a gas sensor to do both gas source localization and distributing mapping and [10] made their own echolocation deck with buzzer + microphones. Let’s see what other sensors will be explored in the future!

Safe Robot Learning Competition

A special mention goes to the Safe Robot Learning competition, organized by the joined TU Munich and Utoronto’s the Learning system & robotics lab (formally known as the Dynamic Systems lab). In this competition, teams could participate with an online competition where they had to finish an obstacle course in simulation. From those that were successful, the finals were done with a real Crazyflie at a remote testbed in the University of Toronto, where the algorithms were put to the ultimate test! The simulation was done in the safe-control-gym framework [12], and the communication with the real Crazyflie was done with the ROS1 based Crazyswarm. We sponsored the first three places with a couple of Crazyflie bundles, so congrats to the winners!

List of IROS 2022 Papers featuring the Crazyflie

  1. Using Simulation Optimization to Improve Zero-shot Policy Transfer of Quadrotors Sven Gronauer, Matthias Kissel, Luca Sacchetto, Mathias Korte and Klaus Diepold
  2. Downwash-aware Control Allocation for Over-actuated UAV Platforms Yao Su , Chi Chu , Meng Wang , Jiarui Li , Liu Yang , Yixin Zhu , Hangxin Liu
    • Beijing Institute for General Artificial Intelligence (BIGAI)
    • ArXiv
    • IEEE Xplore
  3. Towards Specialized Hardware for Learning-based Visual Odometry on the Edge Siyuan Chen and Ken Mai
    • Beijing Institute for General Artificial Intelligence (BIGAI)
    • IEEE Xplore
  4. Polynomial Time Near-Time-Optimal Multi-Robot Path Planning in Three Dimensions with Applications to Large-Scale UAV Coordination Teng Guo, Siwei Feng and Jingjin Yu
  5. GaSLAM: An Algorithm for Simultaneous Gas Source Localization and Gas Distribution Mapping in 3D Chiara Ercolani, Lixuan Tang and Alcherio Martinoli
    • Ecole Polytechnique Federale de Lausanne (EPFL),
    • IEEE Xplore
  6. Efficient 2D Graph SLAM for Sparse Sensing Hanzhi Zhou, Zichao Hu, Sihang Liu and Samira Khan
  7. Avoiding Dynamic Obstacles with Real-time Motion Planning using Quadratic Programming for Varied Locomotion Modes Jason White, David Jay, Tianze Wang, and Christian Hubicki
  8. Dynamic Compressed Sensing of Unsteady Flows with a Mobile Robot Sachin Shriwastav, Gregory Snyder and Zhuoyuan Song
  9. A Framework for Optimized Topology Design and Leader Selection in Affine Formation Control Fan Xiao, Qingkai Yang, Xinyue Zhao and Hao Fang
  10. Blind as a bat: audible echolocation on small robots Frederike Dumbgen Adrien Hoffet Mihailo Kolundzija Adam Scholefield Martin Vetterli
    • Ecole Polytechnique Federale de Lausanne (EPFL)
    • IEEE xplore
  11. Safe Reinforcement Learning for Robot Control using Control Lyapunov Barrier Functions Desong Du, Shaohang Han, Naiming Qi and Wei Pan
    • Harbin Institute of Technology + TU Delft + University of Manchester
    • Late breaking result poster
  12. Parsing Indoor Manhattan Scenes Using Four-Point LiDAR on a Micro UAV Eunju Jeong, Suyoung Kang, Daekyeong Lee, and Pyojin Kim
    • Sookmyung Women’s University,
    • Late breaking result poster
  13. Interactive Multi-Robot Aerial Cinematography Through Hemispherical Manifold Coverage Xiaotian Xu , Guangyao Shi , Pratap Tokekar , and Yancy Diaz-Mercado
    • University of Maryland
    • Note: Only mention of Crazyflie experiments in presentation
  14. Safe-control-gym: a Unified Benchmark Suite for Safe Learning-based Control and Reinforcement Learning in Robotics Zhaocong Yuan, Adam W. Hall, Siqi Zhou, Lukas Brunke, Melissa Greeff, Jacopo Panerati, Angela P. Schoellig
  15. Distributed Geometric and Optimization-based Control of Multiple Quadrotors for Cable-Suspended Payload Transport Khaled Wahba and Wolfgang Hoenig
  16. Customizable-ModQuad: a Versatile Hardware-Software Platform to Develop Lightweight and Low-cost Aerial Vehicles Diego S. D’Antonio, Jiawei Xu, Gustavo A. Cardona, and David Saldaña

Let us know if we are missing any papers or information per papers! Once the IEEE xplore IROS 2022 proceedings have been published, we will update these too and put them on our research page.

In December we had a blogpost where we gave an overview of existing simulation models that were out there. In the mean time, I have done some work during my Fun Fridays to get this to work even further. Currently I moved the efforts from my personal Github repo to the Bitcraze organization github called crazyflie-simulation. It is all still very much work in progress but in this blogpost I will explain the content of the repository and what these elements can already do.

Low Poly CAD model

The first thing that you will need to have for any simulation, is a 3D model of the Crazyflie. There is of course already great models available from the CrazyS project, the sim_cf project and the multi_uav_simulator, which are completely fine to use as well. But since we have direct access to the exact geometries of the real crazyflie itself, I wanted to see if I could abstract the shapes myself. And also I would like to improve my Blender skills, so this seemed to be a nice project to work with! Moreover, it might be handy to have a central place if anybody is looking for a 3D simulation model of the Crazyflie.

For simulations with only one or a few Crazyflie, the higher resolution models from the other repository are absolutely sufficient, especially if you are not using a very complicated physics geometry model (because that is where most of the computation is). But if you would like to simulate very big swarms, then the polygon count will have more influences on the speed of the simulation. So I managed to make it to 1970 vertices with the below Crazyflie model, which is not too bad! I am sure that we can make it even with lesser polygons but this is perhaps a good place to start out with for now.

In the crazyflie-simulation, you can find the Blender, stl files and collada files under the folder ‘meshes’.

Webots model

We implemented the above model in a Webots simulator, which was much easier to implement than I thought! The tutorials they provide are great so I was able to get the model flying within a day or two. By combining the propeller node and rotational motor, and adjusting the thrust and drag coefficient to be a bit more ‘Crazyflie like’, it was able to take off. It would be nice to perhaps base these coefficients on the system identification of the Crazyflie, like what was done for this bachelor thesis, but for now our goal is just to make it fly!

The webots model can found in the same simulation repository under /webots/. You can try out the model by

webots webots/world/crazyfly_world.wbt

It would then be possible to control the pitch and roll with the arrow keys of your keyboard while it is maintaining a current height of 1 meter. This is current state of the code as of commit 79640a.

Ignition Gazebo model

Ignition will be the replacement for Gazebo Classic, which is already a well known simulator for many of you. Writing controllers and plugins is slightly more challenging as it is only in C++ but it is such a landmark in the world of simulation, it only makes sense that we will try to make a Gazebo model of the Crazyflie as well! In the previous blogpost I mentioned that I already experimented a bit with Ignition Gazebo, as it has the nice multicopter motor model plugin standard within the framework now. Then I tried to make it controllable with the intergrated multicopter velocity control plugin but I wasn’t super successful, probably because I didn’t have the right coefficients and gains! I will rekindle these efforts another time, but if anybody would like to try that out, please do so!

First I made my own controller plugin for the gazebo model, which can be found in the repository in a different branch under /gazebo-ignition/. This controller plugin needs to be built first and it’s bin file added to the path IGN_GAZEBO_SYSTEM_PLUGIN_PATH, and the Crazyflie model in IGN_GAZEBO_RESOURCE_PATH , but then if you try to fly the model with the following:

 ign gazebo crazyflie_world.sdfCode language: CSS (css)

It will take off and hover nicely. Unfortunately, if you try out the key publisher widget with the arrow keys, you see that the Crazyflie immediately crashes. So there is still something fishy there! Please check out the issue list of the repo to check the state on that.

Controllers

So the reason why I made my own controller plugins for the above mentioned simulation models, is that I want to experiment with a way that we can separate the crazyflie firmware controllers, make a code wrapper for them, and use those controllers directly in the simulator. So this way it will become a hybrid software in the loop without having to compile the entire firmware that contains all kinds of extra things that the simulation probably does not need. We can’t do this hybrid SITL yet, but at least it would be nice to have the elements in place to make it possible.

Currently I’m only experimenting with a simple fixed height and attitude PID controller written in C, and some extra files to make it possible to make a python wrapper for those. The C-controller itself you can try out in Webots as of this commit 79640a, but hopefully we will have the python version of it working too.

What is next?

As you probably noticed, the simulation work are still very much work in process and there is still a lot enhancements to add or fix. Currently this is only done on available Fridays so the progress is not super fast unfortunately, but at least there is one model flying.

Some other elements that we would like to work on:

  • Velocity controller, so that the models are able to react on twist messages.
  • Crazyflie firmware bindings of controllers
  • Better system variables (at least so that the ign gazebo model and the webots model are more similar)
  • CFlib integration
  • Add a multiranger and/or camera.
  • and more!

I might turn a couple of these into topics that would be good for contribution, so that any community members can help out with. Please keep an eye on the issue list, and we are communicating on the Crazyswarm2 Discussion page about simulations if you want to share your thoughts on this as well.

I have returned from my family visit in California, who I’ve haven’t seen them in 3 years due to Covid. To spend the most possible time with them, the plan was that I would still work full time for Bitcraze from my father’s home. The problem became however, that it wouldn’t fit so well in our current way of work as I would miss all the morning stand up meetings due to the large time difference between Sweden and California (-9 hours). That is why we settled that I would work on separate projects/investigations during my time away. So I thought it would be a great opportunity to dig into ROS and 3D simulations again and see what the latest state of that is! So about the simulations is what I’ll be mostly talking about right in this blog post, in terms of what simulators are out there and what simulation development is currently ongoing.

Need for simulation?

Why would it be actually be necessary to have a simulation in our current frame work? Just to give an example, my new colleague Jonas recently tried out his hand on the CFlib swarm class for the first time for the BAMdays tutorials, and simulator would have been great during that initial porcess. Namely, most of the crashes were not necessary due to low batteries or bad communication, but mostly due to the fact that he was not able to double check his script beforehand. If one is able to check if all the programmed positions of the Crazyflies are implemented as they should before an actual flight, this would prevented a lot of broken propellers!

Just to note here that there are a lot of types of simulations that you can think of. Earlier this year had our ex-interns Max and Josephine finish an Renode simulation of the Crazyflie’s microcontrollers. We’ve also seen the word Simulink pop-up multiple times on the forum which indicates that quite some control classes are investigating the dynamic model of the Crazyflie. However, the type of simulation that I’m currently referring to are the 3D simulators in which a robot or quadcopter can move and interact with a virtual environment, with usually an physics engine in effect.

Crazyflie in Gazebo (+ROS)

During some initial investigation there were already some simulations that pop out. First of all I went and looked into what is available for Gazebo at the moment, which is:

CrazyS is based on the RotorS simulation with some additional off-board crazyflie controllers for position control. I wasn’t able to build it for my Ubuntu 20.04 just yet myself, but that there is ongoing work to port CrazyS to ROS Noetic. For now on a virtual machine with ROS melodic it build just fine! Note my laptop did had to work quite hard when I wanted to simulate more than 1 Crazyflie, but the physics and plugins that were made for Gazebo is enabling many to do a lot for their research. Please check out the core papers about CrazyS!

Sim_cf is perhaps a little lesser known, but the project does stand out as it has some interesting features to it. It is for instance, possible to use the actual c-based firmware in software-in-the-loop (SITL) mode, which controls the simulated Crazyflie. It is even possible to use an actual crazyflie with an hardware-in-the-loop (HITL) simulation. Eventhough the project is not actively maintained anymore, I did manage to build it from source for ROS Noetic and Gazebo 11, although I was not able to fly more than 4 do to errors.

Other Simulators

Ofcourse Gazebo is not the only possibility out there. I also had a quick go at another simulator called Webots, which is quite an interesting option indeed as well. Currently there is only one quadcopter model available, so it only makes sense for it to also contain an Crazyflie! They do use their own robotic format, so probably the easiest process would be, is to convert an existing model for Gazebo/ROS into an format that Webots can understand.

Also, quite recently, a trending tweet has brought us to the attention of a Rviz based Crazyflie simulation! This looks quite promising as well, so I will try this out quite soon too.

Screenshot from 2021-11-15 11-56-48
Crazyflie in Ignition Gazebo

Ongoing work in Ignition Gazebo

So in the future, the current Gazebo in its form will disappear and will be only be part of Ignition. So that is why it made sense for me to start playing with an separate Crazyflie model and plugins for the Ignition frame work instead. Moreover, it seems that quite some elements and plugins based on the RotorS simulation for the original gazebo, are now fully integrated within the Ignition gazebo framework, which should make it more easier to make quadcopter models fly. Currently it’s still work in progress, so right now is only to be found on my personal github repository, but as soon as it becomes more fleshed out and stable, this will probably transferred to Bitcraze’s github repos and we will write a more elaborate blogpost about it. For now, I’ll try to work on it further as my Fun Friday project!

In the mean time, we have started a simulation discussion thread in the Crazyswarm2 repository, which is an ongoing port of Crazyswarm to ROS2. It would be the ideal situation if we would be able to use this simulator for both Crazyswarm and our native CFlib! But I’ve mostly have used Gazebo in the past, so if there are any other simulators that we should try out too, please join the discussion and let us know!