Reproducing YouTube Video (Swarming CrazyFlies)

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TYPark
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Reproducing YouTube Video (Swarming CrazyFlies)

Post by TYPark » Fri Oct 19, 2018 7:25 am

Hi,

We are mainly interested in swarming Crazyflies under autonomous flight, generating formations of interests such as characters or heart shape by the swarm of Crazyflies.

We have purchased and tested Crazyflies with Loco positioning system and decks (Loco, flow, and LED), tying to reproduce the formation given in the following YouTube video:

https://www.youtube.com/watch?v=D0CrjoYDt9w

Particularly, what we are interested in is the part after 1:37 in this video, i.e., making certain shape along the height with swarming Crazyflies.

So far, our test result showed highly unstable flight when using a few Crazyflies with Loco positioning system (8 anchors) at TDoA mode - the test video file is available at the following URL:

https://drive.google.com/file/d/1kk2u-T ... sp=sharing

In this test, the flying path we entered is simply take-off and stay there for 30 seconds, but as you can see, the Crazyflies are not hovering but moving in an unstable manner - maybe because we have made a wrong setting or use wrong device? We used Loco positioning system (8 anchors) and Loco deck in each Crazyflie with LED deck.

My questions are the followings:

1. Our first objective is to reproduce the formation given in the YouTube above (after 1:37). Is this possible with Crazyfiles 2.0 with Loco positioning system and some additional decks?

2. If possible, what device and settings should be used? I guess we should use Loco positioning system (8 anchors) and Loco decks operating at TDoA mode. Do we need to use the flow deck or any other device? It would be great if you could provide a detailed list of H/W and settings to reproduce the YouTube video above.

Many thanks in advance.

whoenig
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Re: Reproducing YouTube Video (Swarming CrazyFlies)

Post by whoenig » Fri Oct 19, 2018 5:04 pm

For the YouTube video, we used a VICON motion capture system, which provides sub-millimeter accuracy. Loco/UWB on the other hand provides 10cm accuracy. You can try pairing the UWB with the flow-deck, which improves the localization a lot, but might create issues if CFs fly on top of each other. Another option would be to use the lighthouse localization system or a motion capture system.

TYPark
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Re: Reproducing YouTube Video (Swarming CrazyFlies)

Post by TYPark » Sun Oct 21, 2018 5:03 am

Great thanks for your reply.

Just a few more questions:

1. If I use Loco/UWB only, can I achieve a stable flight? 10 cm accuracy is good enough for us, but the issue is the unstable flight, i.e., the CrazyFlies cannot do the hovering but moving arbitrarily as shown in the test video.

2. If I use the Flow-deck, can I still attach the LED deck together with the Flow-deck? If so, can you tell how?

3. Would you recommend the lighthouse localization system or the motion capture system commercially available, where to buy with a price range and how to setup?

Many thanks again.

whoenig
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Re: Reproducing YouTube Video (Swarming CrazyFlies)

Post by whoenig » Sun Oct 21, 2018 11:38 pm

1. It won't hover perfectly, but it shouldn't be as unstable as in the test video. You can see in the blog posts (for example, the recent IROS exhibition) what's possible.

2. Not without HW modification. Both of them need to be mounted underneath. Bitcraze had a "glow deck" prototype before that could be placed on top, but it isn't commercially available, yet.

3. The lighthouse deck is not available yet. In terms of motion capture systems, you'll need to get a quote from the vendors (typical vendors: VICON, OptiTrack, Qualisys). It will be several thousand dollars though, depending on the size of the space you want to capture.

TYPark
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Re: Reproducing YouTube Video (Swarming CrazyFlies)

Post by TYPark » Mon Oct 22, 2018 3:39 am

Many thanks for your reply, which helped a lot!

Now, we'd like to test the motion capture systems you mentioned while waiting for your lighthouse system (we definitely want to try your lighthouse system as well when it's available).

Just a few additional questions on the motion capture system if you don't mind:

1. Which system do you recommend among the three vendors (VICON, OptiTrack, Qualisys) based on your experiences or knowledge?

2. Do you have any documentation or guide how to incorporate the motion capture system with CrazyFlies for swarming? As we have zero experience in setting up with the motion capture system, it would be of great help if you could inform where we should start from scratch - we are willing to get your paid consultation on this issue if available.

Great thanks again.

whoenig
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Re: Reproducing YouTube Video (Swarming CrazyFlies)

Post by whoenig » Tue Oct 23, 2018 2:25 am

1. I only really worked extensively with VICON, and it works pretty well and the support from the vendor is very good. Other users have used OptiTrack and Qualisys successfully as well.
2. There is the Crazyswarm, which has documentation here: https://crazyswarm.readthedocs.io/en/latest/. There is no paid support, but we do respond fairly quickly to issues on github. We support VICON, OptiTrack, and Qualisys (although, in-house we can only test with VICON, so the other code is provided by our users.)

Note: I am not affiliated with Bitcraze, but I am a coauthor of crazyflie_ros and the crazyswarm. For the availability of the lighthouse system, you will need to reach out to Bitcraze directly.

TYPark
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Re: Reproducing YouTube Video (Swarming CrazyFlies)

Post by TYPark » Tue Oct 23, 2018 3:03 am

Thank you so much for your reply - helped me a lot!

I'll carefully read the Crazyswarm documentation, and will be back to update our development status.

By the way, we'd like to go for the VICON as you tested. Could you tell us based on your experience what equipment we should buy to run about swarm of 49 CrazyFlies? I visited VICON website and no information on what to use for swarming CrazyFlies, so requested contact to them.

Can you tell what determines the maximum number of CrazyFlies in swarming flight in-house? Limited by the motion capture or CrazyFlies radio or hardware?

Great thanks again.

whoenig
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Re: Reproducing YouTube Video (Swarming CrazyFlies)

Post by whoenig » Wed Oct 24, 2018 8:46 pm

All of the vendors have planning tools, so they should be able to figure out what you need, based on your space and budget. Just specify the marker size (we use 7.9mm markers) and tell them that you are looking for getting a point cloud rather than object tracking.

Limits:
* Practicality: maintenance (including battery swaps) becomes a major factor once you move to so many UAVs. In practice, we mostly fly only half of the swarm to minimize such issues.
* MoCap: The latency increases with the number of markers roughly linearly. I think 100 CFs should be doable (400 markers), but you can also bring that up with the mocap vendor.
* Radio: There is an issue on github that suggests that there are problems with using more than 3 radios. We support about 15 CFs/radio with our firmware and about 30 CFs/radio without yaw correction. In principle you should be just limited by the USB ports and number of CPU cores (one per radio).

TYPark
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Re: Reproducing YouTube Video (Swarming CrazyFlies)

Post by TYPark » Thu Oct 25, 2018 8:47 am

Great thanks for your reply including critical suggestions for us!

We are reading your papers and VICON's manual, trying to figure out some basics (as we are kind of a dummy on the motion capture area). We'll be back and update what we've done.

Again, your help is greatly appreciated.

TYPark
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Re: Reproducing YouTube Video (Swarming CrazyFlies)

Post by TYPark » Mon Nov 05, 2018 3:08 am

Hi,

I'm wondering if I can consult the quotation I received from one of the VICON distributors in South-Korea, if it's the right parts I need for the Crazyswarm and if the price ranges are reasonable... Just let me know as it is a bit off the topic for this Forum.

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