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Discover the Impact of Structural Defects on Nano-Quadcopter Performance: CrazyPAD dataset

  2024-06-24  |     |    Leave a comment

This week we have a guest blogpost by Kamil Masalimov (MSc) and Tagir Muslimov (PhD) of the Ufa University of Science and Technology. Enjoy!

As researchers passionate about UAV technology, we are excited to share our recent findings on how structural defects affect the performance of nano-quadcopters. Our study, titled “CrazyPAD: A Dataset for Assessing the Impact of Structural Defects on Nano-Quadcopter Performance,” offers comprehensive insights that could greatly benefit the Crazyflie community and the broader UAV industry.

The Motivation Behind Our Research

Understanding the nuances of how structural defects impact UAV performance is crucial for advancing the design, testing, and maintenance of these devices. Even minor imperfections can lead to significant changes in flight behavior, affecting stability, power consumption, and control responsiveness. Our goal was to create a robust dataset (CrazyPAD) that documents these effects and can be used for further research and development.

Key Findings from Our Study

We conducted a series of experiments by introducing various defects, such as added weights and propeller cuts (Figure 1), to nano-quadcopters. For the experiments, we used the Lighthouse Positioning System with two SteamVR 2.0 virtual reality stations (Figure 2).

Figure 1. Propeller with two side defects
Figure 2. Schematic of the experimental setup with Lighthouse Positioning System

Here are some of the pivotal findings from our research:

  1. Stability Impact: We observed that both added weights and propeller cuts lead to noticeable changes in the stability of the quadcopter. Larger defects caused greater instability, emphasizing the importance of precise manufacturing and regular maintenance.
  2. Increased Power Consumption: Our experiments showed that structural defects result in higher power consumption. This insight is vital for optimizing battery life and enhancing energy efficiency during flights.
  3. Variable Control Responsiveness: We used the standard deviation of thrust commands as a measure of control responsiveness. The results indicated that defects increased the variability of control inputs, which could affect maneuverability and flight precision.
  4. Changes in Roll and Pitch Rates: The study also highlighted variations in roll and pitch rates due to structural defects, providing a deeper understanding of how these imperfections impact flight dynamics.

We show Figure 3 as an example of a graph obtained from our dataset. In this figure, you can see the altitude and thrust command over time for different flight conditions. The blue line represents the normal flight, while the orange line represents the flight with additional weight near the M3 propeller. In Figure 4, you can see the 3D flight trajectory of the Crazyflie 2.1 quadcopter under the cut_propeller_M3_2mm condition with the corrected ideal path. The blue line represents the actual flight trajectory, while the red dashed line with markers represents the ideal trajectory. Figure 5 shows the Motor PWM values over time for the add_weight_W1_near_M3 condition. The plot shows the PWM values of each motor (M1, M2, M3, and M4) as they respond to the added weight near the M3 propeller.

More examples of graphs obtained from the CrazyPAD dataset can be found in our research paper specifically describing this dataset: https://doi.org/10.3390/data9060079

Figure 3. Altitude and thrust command over time for different flight conditions
Figure 4. 3D flight trajectory of the Crazyflie 2.1
Figure 5. Motor PWM values over time

Leveraging Research for Diagnostic and Predictive Models

One of the most exciting aspects of our research is its potential application in developing diagnostic and predictive models. The CrazyPAD dataset can be utilized to train machine learning algorithms that detect and predict structural defects in real-time. By analyzing flight data, these models can identify early signs of wear and tear, allowing for proactive maintenance and reducing the risk of in-flight failures.

Diagnostic models can continuously monitor the performance of a UAV, identifying anomalies and pinpointing potential defects. This real-time monitoring can significantly enhance the reliability and safety of UAV operations.

Predictive models can forecast future defects based on historical flight data. By anticipating when and where defects are likely to occur, these models can inform maintenance schedules, ensuring UAVs are serviced before issues become critical.

Why This Matters for the Crazyflie Community

The CrazyPAD dataset and our findings offer valuable resources for the Crazyflie community. By understanding how different defects affect flight performance, developers and enthusiasts can improve design protocols, enhance testing procedures, and ensure higher safety and performance standards for their UAVs.

We believe that sharing our research with the Crazyflie community can lead to significant advancements in UAV technology. The dataset we created is open under the MIT License for further exploration and can serve as a foundation for new innovations and improvements.

Get Involved and Explore Further

We invite community members to explore our full research article and the CrazyPAD dataset. Together, we can drive forward the standards of UAV technology, ensuring that Crazyflie remains at the forefront of innovation and excellence.

Our research paper with a detailed description of this dataset:

Masalimov, K.; Muslimov, T.; Kozlov, E.; Munasypov, R. CrazyPAD: A Dataset for Assessing the Impact of Structural Defects on Nano-Quadcopter Performance. Data 2024, 9, 79. https://doi.org/10.3390/data9060079

Dataset:  https://github.com/AerialRoboticsUUST/CrazyPAD

We are eager to collaborate with the Crazyflie community and welcome any feedback or questions regarding our research. Let’s work together to push the boundaries of what’s possible in UAV technology.

SWEDISH SUMMER, 2024 edition

  2024-06-17  |     |    Leave a comment

If you know a little about Sweden, you know about Midsommar. Nothing like the 2019 horror film (thankfully), though we do wear flower crowns and dance around the pole. It’s usually an occasion to celebrate with family (and alcohol) those long days and short nights. We actually celebrated a little bit early today with a nice team barbecue.

Midsommar is next Friday, and it marks the official kickoff to summer here in Sweden. That also means that for the coming 2 months, Bitcraze will be operating with a slightly smaller team. So, what does that mean for you? This should not impact you too much, of course, but here are the most important things to note:

  • Developer Meetings: First up, our regular developer meetings will be on hiatus during July and August. It’s a great time for everyone, including you, our regular attendees, to take a breather. We’ll be back in action come September, resuming our usual schedule of one meeting per month.
  • GitHub: With fewer team members around, our response time on GitHub discussions might be a bit slower. We strive to answer every question, but with less manpower, some issues might only get resolved when the person with the right expertise returns from their vacation. We appreciate your patience and understanding during this time.
  • Orders: Shipping and deliveries should have the same pace, so don’t worry about your order coming on time, we’ve got that covered!

Ongoing projects and maintenance

Our focus during the summer will shift primarily to maintenance and continuing work on ongoing projects. We’re putting the final touches on the Brushless project of course, and will keep working on its charger solution too.

We’re excited to announce our participation in Robotics Developers Day on July 5th. We’re not only sponsors of this event, we’re also thrilled that Kimberly will be hosting a live learning session about ROS 2 on the Crazyflie.

For us at Bitcraze, summer is a wonderful opportunity to slow down a bit and focus on projects we don’t usually have time for. This could mean diving deeper into learning RUST, reorganizing the office, or trying some prototypes out. It’s a chance to reset and prepare for the busy months ahead.

We hope you have a fantastic summer filled with sunshine, relaxation, and lots of new adventures. Glad Midsommar, as we say here!

ICRA 2024 POSTERS

  2024-06-10  |     |    Leave a comment

As we mentioned earlier, ICRA Yokohama was full of exciting encounters – we really enjoyed meeting researchers, tech companies, and enthusiastic roboticists during those 4 days.

One challenge was to bring back as many research posters featuring the Crazyflies as possible. The goal was to decorate the walls of the office with them, as a “hall of fame”. And I’m really, really proud to show you how it turned up!

This was before
And this is now!

In total, we received 6 new posters. Here they are:

Optimal Collaborative Transportation for Under-Capacitated Vehicle Routing Problems using Aerial Drone swarms
Akash Kopparam Sreedhara, Deepesh Padala, Shashank Mahesh, Kai Cui, Mengguang Li, Heinz Koeppl

This paper presents a strategy for optimizing the collaborative transportation of payloads in an under-capacitated vehicle routing scenario. The Crazyflies work together to dynamically adjust routes based on real-time data and transport capacities, and collaborate to lift and transport heavier payloads.

From Shadows to Light: A Swarm Robotics Approach With Onboard Control for Seeking Dynamic Sources in Constrained Environments
T. A. Karagüzel, V. Retamal, N. Cambier and E. Ferrante

The paper describes a method for enabling a swarm of Crazyflies to dynamically seek and locate a moving target or source in constrained, GNSS-denied environments. Using a simple rule-based approach, the drones track dynamic source gradients and navigate obstacles autonomously with fully onboard systems.

CrazySim: A Software-in-the-Loop Simulator for the Crazyflie Nano Quadrotor
Christian Llanes, Zahi Kakish, Kyle Williams, and Samuel Coogan

We actually already have a blogpost presenting this paper, and we’re so happy to have it represented in our office now!

TinyMPC: Model-Predictive Control on Resource-Constrained Microcontrollers
Khai Nguyen, Sam Schoedel, Anoushka Alavilli, Brian Plancher, Zachary Manchester

The paper presents TinyMPC, a high-speed model-predictive control (MPC) solver designed for resource-constrained microcontrollers on small robots like the Crazyflie. TinyMPC efficiently handles real-time trajectory tracking and dynamic obstacle avoidance, outperforming traditional solvers.

Robust and Efficient Depth-Based Obstacle Avoidance for Autonomous Miniaturized UAVs
H. Müller, V. Niculescu, T. Polonelli, M. Magno and L. Benini

The paper introduces a lightweight obstacle avoidance system for nano quadcopters, leveraging a novel 64-pixel multizone time-of-flight (ToF) sensor to safely and effectively navigate complex indoor environments. Tested on the Crazyflie 2.1, the system achieves 100% reliability at a speed of 0.5 m/s, all while using only 0.3% of the onboard processing power, demonstrating its suitability for autonomous operations in unexplored settings.

Fully onboard Low-power localization with semantic sensor fusion on a Nano-UAV using floor plans
Nicky Zimmerman, Hanna Müller, Michele Magno, Luca Benini

This paper introduces a method for autonomous localization in nano-sized UAVs like the Crazyflie by fusing geometric data from time-of-flight sensors with semantic information extracted from images. The approach leverages annotated floor plans to improve navigation accuracy without adding extra deployment costs. The system operates efficiently with limited onboard computational resources, achieving a 90% success rate in real-world office environments.

A big thanks, once again, to all of those who gave us their posters!

The Aerial Robotic Landscape

  2024-06-03  |     |    Leave a comment

It’s been over a little year since we started the ROS Aerial Robotics community group together with the Drone Code Foundation, and it is still going strong (blogpost 1, blogpost 2). Since there is a nice mix of people joining the meetings from different backgrounds and drone operating systems, we have had quite a few discussions and overviews of various topics. For instance, we’ve explored courses in Aerial Robotics and other subjects in previous meetings. An important goal of the group has been to make it easier for people to get started with flying robotics, which we’ve achieved by collecting essential information in the ‘Aerial Robotic Landscape’.

Starting out in Aerial Robotics

Let’s cut to the chase: Aerial Robotics is a very challenging field to get started in. Not only do you need a comprehensive understanding of which hardware to acquire, but users also face a multiple choices. These decisions include selecting the right autopilot, simulator for testing ideas, and necessary sensors to achieve autonomy. Unlike the well-established Turtlebot in other robotics domains, there isn’t a universally accepted and field-tested getting-started development drone in the aerial robotics world. While we at Bitcraze would love everyone to go for the Crazyflie, we recognize its limitations. Like, it may not handle outdoor flights with GPS or carry heavy cameras effectively. Our goal, as the ‘Aerial Robotics Community group,’ is to make it easier for beginners by providing users with information about the hardware and software they truly need.

Drone Code Foundation and Bitcraze AB had a keynote speech together at ROSCon 2023 about getting started in Aerial Robotics called ‘Up, Up, and Away: Adventures in Aerial Robotics’. Please take a look at the talk here on Vimeo.

The Aerial Robotics Landscape website

The Aerial Robotics Landscape serves as a repository of information related to all things Aerial Robotics. It started out in the GitHub repository, and it grew due to the discussions held at the aerial robotics community group meetings. Additionally, contributions from both group members and external contributors have played an important role (you can explore the merged PRs).

As the pages and tables expanded, it became clear that a better representation was necessary than just the mere README documentation on the GitHub repository. The group therefore experimented with MKDocs, creating a website in the ‘Read the Docs’ theme. This is a similar theme that important packages within in the ROS ecosystem use, such as the ROS documentation, as well as ROS 2 packages like Nav2 and Crazyswarm2.

Please take a look at the rendered website here: https://ros-aerial.github.io/aerial_robotic_landscape/

Please contribute!

The Aerial Robotics Landscape is a dynamic , where development kits emerge while others are discontinued, new simulators rise while some remain unsupported, and autopilot and autonomy features evolve monthly. This ever-changing landscape demands constant updates and additions. We try to do this to the best of our ability, but we can’t do it alone — we need your help.

If you believe that your favorite hardware platform is missing from the landscape, or if you’ve recently developed a new planning algorithm for fixed-wing vehicles or created a YouTube course on optical-based flight, please contribute by means of a pull request to the GitHub repository. We’ve put together a guide on how to contribute to the Aerial Robotics Landscape here. Let’s make the website useful together!

If you’d like to join the ROS aerial Robotics meetings, please take a look at our community github repository for joining information. The next meeting is the 5th of June, 4 PM UTC and was announced on ROS discourse.

Back from ICRA 2024

  2024-05-27  |     |    Leave a comment

Two weeks ago, Arnaud, Barbara and Rik were at ICRA 2024 in Yokohama. At our booth we showed our current products as well as the upcoming brushless Crazyflie and the camera deck prototype.

As usual, the conference has been very busy with a lot of visitors and a lot of very interesting discussion. Thanks to everyone that passed by the booth, we have come back to Sweden with a lot of energy and new ideas!

The autonomous lighthouse swarm demo demo has worked pretty well. If you are interested to know more about it you can visit our event page. It is an autonomous demo with 3 brushless Crazyflies and 6 Crazyflie 2.1s flying autonomously. With the extended battery life of the brushless, we could operate the demo pretty much continuously.

If you’ve been at the conference, you may have spotted someone proudly sporting our exclusive ‘Bitcraze took my poster’ button. We’re excited to have received posters covering a wide range of topics, the walls of our office are eagerly awaiting these visual representations of your hard work and dedication. Thank you to everyone who has contributed.

The Crazyflie 2.1 brushless is getting optional propeller guards

  2024-05-21  |     |    3 Comments

One of the great features of the stock Crazyflie 2.1 is that it is more or less harmless. The Crazyflie 2.1 brushless weighs roughly the same but has almost twice the amount of thrust force, so a little bit of more care is needed. We therefore decided to provide optional propeller guards. While propeller guards adds safety they also add weight and disrupt the air flow from the propellers. Adding to that, the weight is located far from the center which increases the inertia even further, resulting in a less agile drone. For some applications this is not a problem but for others it is, this is why we are making them optional, meaning they are easy to replace with simple landing legs by utilizing a snap-on fitting.

The design is not fully finalized yet but we are getting close, voilá!

If the design goes according to plan they will also withstand some bumping against walls which will be a very nice feature for many applications.

Further the landing legs and propeller guards are designed in a way so they will detach during high force impacts to prevent the PCB arms from breaking.

Come see us at ICRA 2024 Yokohama!

  2024-05-13  |     |    Leave a comment

“What? You are in Japan? Again!?”. Yup that is right! We loved IROS Kyoto 2022 so much that we just couldn’t wait to come back again. Barbara, Arnaud and Rik are setting up the booth as we speak to show some Bitcraze awesomeness to you! Come and say hi at booth IC085.

The gang before the rush starts!

Crazyflie Brushless and Camera expansion

Of all the prototypes we are the most excited of showing you the Crazyflie Brushless and the ‘forward facing expansion connector prototype’ aka the Camera deck. Here you can see them both in action at a tryout of our demo. We have also written blogposts about both so make sure to read them as well (Brushless blogpost, Camera expansion blogpost)

The Crazyflie Brushless flying with a Camera deck.

Also we will explain about the contact charging prototype (see the blogpost here) and will be showing all of our decks at the booth as well. And of course our fully autonomous, onboard, decentralized peer-to-peer and avoiding swarm demo will be displayed as always. Make sure to read this blogpost of when we showed this demo at IROS 2022 to understand what is fully going on!

Also take a look at our event page of the ICRA 2024 demo.

Hand in your Crazyflie posters at our booth!

We will be providing a ‘special disposal service’ for your conference poster! We would love to see what you are working on and get your poster, because we have a lot of space in our updated office/flight space but a lot of empty walls.

If you hand in your poster at the booth, you’ll get a special, one-of-a-kind, button badge that you can wear proudly during the conference! So we will see you at booth IC085!

The ‘Bitcraze took my poster’ button!

New industrial postdoc at Bitcraze

  2024-05-06  |     |    2 Comments

Hello to the awesome Bitcraze community!

My name is Joseph La Delfa, I started in December last year as an industrial postdoc at Bitcraze. This means I work across Bitcraze HQ in Malmö and the division of Robotics Perception and Learning at KTH in Stockholm. I have been designing and researching interactions that involve bodily control of drones for a few years now.

In order of appearance: Demonstrating at a conference, mucking around with the Qualisys tab, coaching at Drone Arena I, playing judge at Drone Arena II, and finally Drone Chi.

Here at Bitcraze I will be using lighthouse decks on the body to control Crazyflie/s, with the aim to produce a wearable sensor that integrates into the Bitcraze ecosystem. The lighthouse positioning system is showing great potential for this application as it gives relatively clean and high-fidelity positional data. Plus now that more than two base stations can be used, we can potentially track the deck from top down and bottom up.

Three motor-less crazyflies are strapped to my arms and tracked using two lighthouse basestations.

This research is a continuation of my PhD thesis, where I designed drone interactions that respond differently to different people, and advocated for a human-drone relationship that evolves over time. Ultimately I hope to demonstrate new use cases for the Crazyflie and expand the already impressive community of researchers who use Bitcraze products!

How to Train Your Drone was a one-month field study in a shared home, where three housemates taught their drones how to fly.

This industrial postdoc is funded by the Wallenberg AI, Autonomous Systems and Software Program (WASP), and you can find out more about my work at www.cafeciaojoe.com :D

Prototype of forward facing expansion connector

  2024-04-29  |     |    2 Comments

A great feature of the Crazyflie is its ability to keep evolving, both by using software but also through hardware expansions. Hardware expansions allow us and our users to keep exploring new problems and doing new experiments, without having to change the flying base. Over the years lots of new decks have been released and we’ve seen lots of users building their own custom electronics and attaching it to their Crazyflies. Although very versatile, the current deck system is limited to up/downwards facing expansions. Adding electronics that face forward, like a camera, has been harder and has required additional mechanics. Over the last couple of months we’ve been experimenting with a new expansion connector aiming at solving this issue. The idea is to be able to add a new class of expansions facing forward. This week’s blog post and next week’s developer meeting are about these experiments.

Goals and design

We’re always trying to find ways to make our platform more versatile, making it easier to expand and to be used in new ways. So we’ve been looking for a new way to be able to expand the platform even more, this time with electronics facing forward instead of up/down. The goal is to easily be able to add things such as cameras, ranging sensors etc. Making a custom deck with custom mechanics for each sensor hasn’t been a good solution, it takes lots of time and it doesn’t enable our users to do their own custom electronics. Finding a generic solution is hard since we’re constrained both in space and in weight. We need a solution which is very small and light, each gram adding cuts into the flight time. The solution also needs a way to handle the data generated from cameras/sensors as well as possibly to stream it over a faster connection than the Crazyradio.

Our current prototype is made of two parts, a new deck with WiFi and more computational power as well as several smaller expansions which can be added to it. The expansions fit straight into a small right angle connector, making it easy to change boards. The current connector we’re testing has 30 positions, of which 6 is used for power and 1 for 1-wire, leaving 24 pins for signaling. The 1-wire works the same way as our current decks, additional added hardware is auto-detected at startup and can be used without recompiling or reconfiguration.

The current prototype uses an ESP32-S3 and weighs in at 3.7 grams. Added to this there are a number of expansions that we’re evaluating:

  • OV2640 + VL53L5CX: RGB camera and ranging sensor (1.6 grams)
  • Flir Lepton 3.5: Thermal camera (2.1 grams)
  • MLX90640: Thermal camera (2.0 grams)

So the current prototype with RGB camera (and ranging sensor) weights in at a total of 5.3 grams (0.9 grams more than the AI deck).

Current status and continuation

We’re currently experimenting with connectors, modules and dimensions. In the coming months we will try to get more flight time to test the solution and we’re hoping to get some feedback from our users. So please post any comments and/or suggestions you might have.

If you’re interested in knowing more and discussing this then join our developer meeting next week on Wednesday. We will also be showing off the prototypes at ICRA, so make sure to swing by the booth if you’re attending.

ICRA 2024 and other news

  2024-04-22  |     |    Leave a comment

ICRA Yokohama

From the beginning of the company, we’ve always loved to join in at conferences. Only at a conference do you get the opportunity to show our products, meet our users or other tech-oriented people, learn about what others are doing, and let’s not forget the chance to discover a new place!

This year, we’ll be present at ICRA Yokohama – it’s in just 3 weeks. We’ll have a booth there (IC085 if you’re looking for us). We’ll be showing our autonomous demo with a twist just like we have shown last time, so please check the event page. This demo is extremely impressive and we’ve been improving on it each time we’ve shown it – beginning in our latest Japan trip and lastly at the last ICRA too. What’s new?

We’re really excited to be showing that and receive feedback, but also in hearing about what our users have been doing. ICRA is always a perfect place to catch up on all the amazing papers and publications featuring our hardware, and we couldn’t be prouder of all the cool stuff we’ve seen so far. We’re so proud, in fact, that we want to be able to show off! So, if you have a paper or a publication featured at ICRA, let us know – you can write us an email at contact@bitcraze.io, leave a comment below this post, or pass by our booth.

In fact, we’re prepared to make a deal. If you have a nice poster featuring our products and don’t know what to do with it once you’ve presented it, pass by our booth! We’re ready to swap them for something extra special. We plan to have a “hall of fame” at the office featuring your awesome work – in fact, it’s an idea we had last ICRA when someone just offered us their posters. Now, we’d like to cover our walls with them!

The corridor leading to the kitchen – we have space to show off the awesomeness!

So, whether you’re a seasoned conference-goer or a first-time attendee, don’t hesitate to wsing by our booth, say hello, and discover our newest demo! We hope to see you there.

Dev meeting

Next developer meeting is going to be on the 8th of May – we traditionally have a dev meeting every first Wednesday of the month, but this time it happens to be on the 1st of May which is a holiday here in Sweden. So already prepare your calendar for the 8th of May at 15.00 CET, and stay tuned for more info on which topic we’ll talk about!

Crazyflies back in stock !

You may have noticed that the Crazyflies have been out of stock for some time now. After some adventures, we are now fully back in stock with most of our bundles and products available in the shop!