lighthouse system -- buyers guide

Discussions related to positioning systems where the position is calculated outside the Crazyflie and sent to the device using radio, including MoCap systems
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tvlqr
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lighthouse system -- buyers guide

Post by tvlqr » Thu Mar 19, 2020 5:35 am

Hi,

I am a PhD student working on a research project about a palm-sized quadrotor flying in indoor environments with high-precision external position systems. I came across your product line and it looks like this is the perfect hardware platform for me. So I would like to learn a bit more before placing an order. Basically, I have the following system requirements in mind:

- I need a palm-sized quadrotor that allows me to implement my own attitude and altitude control algorithms in C++ or python. Specifically, this means I can fetch IMU sensor data, implement my own algorithm to compute PWM signals, and send these signals to rotors. It would be better if I can implement it on a remote computer and communicate with the quadrotor via telemetry but onboard control is ok too.

- I need an external position system that can give me high-precision pose information (x, y, z, roll, pitch, yaw) at a high frequency. Something like Vicon or OptiTrack would be ideal but they are very expensive. Moreover, I need to set up the system in an apartment so space is a bit constrained.

I skimmed over your products and it looks like your crazyflies v2.1 + lighthouse position system could satisfy my needs. My questions are as follows:
- Regarding the quadrotor and accessories, which crazyflies bundle is the most suitable for me?
- Regarding the lighthouse system, I noticed an old post published in Jun 2019 mentioning a) it did not provide the angular information and b) the absolute error was constant and +/-10cm and the relative error was in millimeters at that time. Is there any update on the accuracy of your lighthouse system now?

Thank you!



kimberly
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Re: lighthouse system -- buyers guide

Post by kimberly » Thu Mar 19, 2020 2:10 pm

Hi!

So for setting up a positioning system in an enclosed space as your apartment, the lighthouse system would be perfect. I'm trying to do the same at my place :D due to the Covid Virus disabling us to work from our office.

Anyway, you should probably go for a getting started bundle for a crazyflie and crazyradio PA. The lighthouse deck is sold separately and you have to purchase the htc vive basestations v1 (times 2) at your local electronics/gaming (online) store.

The implementation of the lighthouse has changed. Full pose is not yet integrated but yaw is, which already makes a whole lot of difference. Also we implemented 1 basestation tracking to deal with occlusion (but still you should have 2 though). I would say that the 10 cm global accuracy was more of a calibration issue and is now less, but the milliliter accuracy still holds. We also as of recently intergrated a new way of calibrating the system, see the documentation here.(https://www.bitcraze.io/docs/crazyflie- ... _overview/)

Good luck and let us know if you have any more questions

tvlqr
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Re: lighthouse system -- buyers guide

Post by tvlqr » Thu Mar 19, 2020 7:54 pm

Thank you for your really helpful reply! I have a follow-up question: so I noticed your product can also be used together with mocap systems. Would it be realistic to set up a small Qualisys mocap system in an apartment (we have a space of roughly 2.5m x 2.5m x 2m) and use it to assist the control of crazyflies? If you have done something similar before, would you mind sharing the Qualisys hardware specifications with us (e.g., the exact number and model of their cameras)? Also, for crazyflies, is there anything else that I need to buy for using mocap, besides the markers and your mocap maker deck?

Thank you!

kristoffer
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Re: lighthouse system -- buyers guide

Post by kristoffer » Fri Mar 20, 2020 6:25 am

Hi!

I think it would work to use a Qualisys system in that space, but you should check that with Qualisys. We had a flying space in our previous office that was around 3x3x2.5 m, that was covered by a Qualisys system. We can provide a contact at Qualisys if you like, email us at contact@bitcraze.io.

With a Qualisys system you have two options: active or passive markers. The Active marker deck (https://store.bitcraze.io/collections/d ... arker-deck, just released) has LEDs instead of passive markers that are tracked by the cameras. The active markers also has their own IDs, which improves tracking and 6-dof estimation. If want passive markers, you can use the passive marker deck or glue them to the Crazyflie.

Note that a Qualisys and Lighthouse system can not be used at the same time as the camera flashes from the mocap system interferes with the Lighthouse sweeps.

You should not need any more equipment to use a mocap system. The main difference is in software as the estimated position has to be transmitted from the mocap system to the Crazyflie(s) continuously. https://crazyswarm.readthedocs.io/en/latest/ is a good tool for this, or a python script.

tvlqr
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Re: lighthouse system -- buyers guide

Post by tvlqr » Fri Mar 20, 2020 3:03 pm

That's very helpful! I will email contact@bitcraze.io if I have further questions. Thank you!

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