Priority of Lighthouse and Flow Deck

Firmware/software/electronics/mechanics
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t.yoneda
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Joined: Mon May 17, 2021 3:03 am

Priority of Lighthouse and Flow Deck

Post by t.yoneda »

Hello.

I'm trying to use Flow deck in addition to lighthouse to improve the stability of crazyflie.
Are there any priority between each positioning systems?
kimberly
Bitcraze
Posts: 1050
Joined: Fri Jul 06, 2018 11:13 am

Re: Priority of Lighthouse and Flow Deck

Post by kimberly »

Hi!

There is no priority between these systems. The lighthouse sweep angles contribute to position estimate in the kalman filter and the flowdeck's flow contributes to the velocity estimate. If it were two position contributors (like LPS and lighthouse together) than the global coordinate system need to match, but that is not necessary for the lighthouse + flowdeck combo as the flowdeck does not rely on a global coordinate system (relative localization)


But... what I'm perhaps a bit more worried about, why you would need a flowdeck to improve the lighthouse positioning performance? The flowdeck measurement noise is much higher than the sweep angles from the lighthouse system... so you should not need to use it at all. Are you sure that the LH system is configured correctly?
t.yoneda
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Re: Priority of Lighthouse and Flow Deck

Post by t.yoneda »

thanks kimberly.

I've come to understand that there are no priorities :D

I'm tring to use flowdeck and lighthouse for swarming.
when swarming, the light reception of lighthouse is sometimes unstable due to the overlapping of the crazyflies.
so I'm trying to use Flowdeck to increase stability.
t.yoneda
Beginner
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Joined: Mon May 17, 2021 3:03 am

Re: Priority of Lighthouse and Flow Deck

Post by t.yoneda »

I'm thinking that Lighthouse light receiving instability is caused by physical shading (e.g., overlap between crazyflie) ,sunlight and hardware trouble, but are there other causes?

In case of hardware problems, restarting crazyflie several times will improve the situation.

So I wanted to reboot remotely, so I used power_switch, but unlike the physical power button on crazyflie, it did not improve the status of lighthouse deck.
Is there any other way to initialize the lighthouse deck other than power_switch?
arnaud
Bitcraze
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Re: Priority of Lighthouse and Flow Deck

Post by arnaud »

This is odd.

On the hardware side, you should check that the lighthouse deck is actually well started. Then the Crazyflie is fully started, the deck's Blue LED should be ON and the Red LED should be OFF. Then the green LED will be lit when everything goes well and there is good signals coming into the deck, but Blue ON and Red OFF is very important since it means that the deck has started (blue on) and is not anymore in bootloader mode (red off).

One thing you could try otherwise is to reset the Kalman filter. The Kalman filter is the only think that actually holds a long-held state so it is the only one that should have an effect when restarting the Crazyflie. This can be done using a parameter, for example this is how we do it in one of our example: https://github.com/bitcraze/crazyflie-l ... #L103-L105. As you can see in the example we also wait for the estimated position to stabilize, this has been a very good things to do in our experience since it will also lock Crazyflie that do not have a working deck from starting.
t.yoneda
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Re: Priority of Lighthouse and Flow Deck

Post by t.yoneda »

Hello, arnaud

The deck has been started successfully.
https://drive.google.com/file/d/1vNCfiP ... sp=sharing

The deck is lit orange and the cfclient lighthouse indicator is red when the deck is not receiving Lighthouse.
the crazyflie sometimes does not receiving lighthouse when the crazyflie put in position to receive Lighthouse.(the deck lit orange) This can be fixed by rebooting the crazyflie with the power button, but I would like to do this remotely.

I have tried PowerSwitch and reset_estimater as you suggested, but that didn't change the situation.

Is there any other way to do it?
t.yoneda
Beginner
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Joined: Mon May 17, 2021 3:03 am

Re: Priority of Lighthouse and Flow Deck

Post by t.yoneda »

Continued verification revealed that it could be a hardware problem with the deck.
I will continue to verify such as the positioning of the deck and the base station.
kimberly
Bitcraze
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Joined: Fri Jul 06, 2018 11:13 am

Re: Priority of Lighthouse and Flow Deck

Post by kimberly »

oke great! thanks for the update. Let us know if you find anything else!

have a great weekend
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