Stability problem

[Blkat94]

Hi. I've just bought the crazyflies 2.1 brushless bundle with 10 drones. Now i'm operating just with one drone to check if everything is working. But, even if everything is connected and well working, when i press "take flight", the drone fly in any direction without stabilization. Which could be the problem?
I'm using the loco positioning system and every single anchor is showed in the correct position (measured and written in the anchor) in the loco positioning tab in the Crazyflie client.

[ArisMorgens]

Hello @Blkat94!

A common mistake when using the Loco Positioning system is the initial orientation of the platform. Since the system doesn't track yaw, the Crazyflie should be placed with 0 initial yaw on the floor. If the yaw is not close to 0, the Crazyflie will start flying uncontrollably trying to "calibrate" itself after some time.

Let us know if this solves your issue or if we need to further investigate it.

[Blkat94]

VID-20251228-WA0001.mp4

Still unstable flight. Even if I placed all correctly. Maybe I'm still missing something...

VID-20251228-WA0002.mp4

[ArisMorgens]

Hello @Blkat94!

The system seems to be set up correctly, so, let's investigate the potential technical details that lead to unstable flights.

On the 1st video, the drones on your back seem to match the expected behavior when flying with the Loco Positioning system, while the ones in front of you seem way more unstable. This might result from the anchor placement or some flight area characteristics, like reflecting surfaces or obstacles blocking the signals. An easy way to identify if your system has lower accuracy on some areas of your flying space, is by placing a Crazyflie to different places and checking the positioning data in the Loco Positioning tab in the cfclient.

Another reason could be the radio bandwidth of each Crazyflie. In order to avoid any interference, it should be set to 2Mbit/s (the default one), so make sure that you didn't modify it.

On the 2nd video, what's the expected result? Should all Crazyflies hover at the same height or at different ones?

[Blkat94]

The expected result is just a take off, hovering at the same hight for some seconds and then softly land. Maybe my worst enemies could be the large mirrors surrounding the dance studio's room. I didn't expect that. Next try is to place the system in a room without reflective surface.

Is there an example file to try a swarm of 10 drones with the lps? ( other question... in the python file does i have to activate in somehow the lps system by coding or it just work anyway by it self?)

[ArisMorgens]

All the decks attached to the Crazyflies are auto-detected and should work out of the box.

There are a bunch of swarming examples but the simplest one for synchronized choreographies has to be this one, where all the connected Crazyflies execute the movements specified in run_shared_sequence. The relative=True argument makes all movements being relative to the current position of each drone.

Let me know if you have any questions on swarming scripts.