Keeping the quadcopters stand still in the air

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mnguyen284
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Posts: 2
Joined: Sat Feb 16, 2019 6:00 am

Keeping the quadcopters stand still in the air

Post by mnguyen284 » Sat Feb 16, 2019 6:44 am

Hi,

I managed to get the LPS up and running. Please see the image in attachment for my setup. Note that the 7, 2 and 6, 3 couples are quite closed to each other (about 1.9m).
Annotation 2019-02-16 132918.jpg
There's a few things in my observation:

1. The blue dot never stands still even though the quadcopter is standing on the table. For example the x would goes from 1.88 to 1.90 continuously.

2. When I fly 4 quadcopters at the same time using swarmSequence.py script, the quadcopters look quite unstable. Please see the video at the link.
https://youtu.be/tZppOWcdR4M

I expect the quadcopters to go up and stand then go down and land without swinging around themselves like that. What's the factor should I look at?

Thank you very much!
Minh

Yoyasp
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Posts: 16
Joined: Mon Jan 14, 2019 2:41 am

Re: Keeping the quadcopters stand still in the air

Post by Yoyasp » Sun Feb 17, 2019 11:12 pm

Hey mnguyen,

the 2 cm variation is normal (atleast its also present with other drones). This is due to up to 10 cm accurate distance readings from the sensors.

As for the degraded performance with multiple drones: Are you using TWR (two way ranging?) or TDoA (Time difference of arrival)?. If you are using TWR the performance will drop as each drone will have to respond to all the anchors, because of all these packets the localisation will be slower and might cause these kind of issues. You should try switching to TDoA using this page: https://www.bitcraze.io/getting-started ... m/#intro26
If you are using TDoA im kinda clueless, sorry...

mnguyen284
Beginner
Posts: 2
Joined: Sat Feb 16, 2019 6:00 am

Re: Keeping the quadcopters stand still in the air

Post by mnguyen284 » Mon Feb 18, 2019 4:24 am

Hi Yoyasp,

Thanks for your response. I'm actually using TDoA (as you can see in the picture). Have you checked the video? Is it supposed to be better? If yes then I have to find another location for more testing.

Thank you,
Minh

tobias
Bitcraze
Posts: 1863
Joined: Mon Jan 28, 2013 7:17 pm
Location: Sweden

Re: Keeping the quadcopters stand still in the air

Post by tobias » Mon Feb 18, 2019 3:20 pm

Judging from the video the performance should be a bit better then that. Some movement (z is the worst) is to be expected. Airflow can actually be one of the disturbances since it is quite a small place. If you have the possibility to use another location that would be the first thing to try.

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