Modelling and Control of Crazyflie

Discussions and questions about the Crazyflie Nano Quadcopter
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Calvin Chua
Beginner
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Joined: Sun Mar 01, 2020 1:28 am

Modelling and Control of Crazyflie

Post by Calvin Chua » Thu Mar 05, 2020 9:37 am

Hi, I am a new user to crazyflie. Is it possible to code using cflib to control the speed of individual motor instead of using the prebuilt function such as forward() etc. Besides, I am thinking of model the crazyflie and is it possible that could you provide me some system parameters of Crazyflie 2.1 such as moment of inertia please? I found some references from others research but they are slightly different I am worried about the accuracy of the parameters.

Thanks Regards,
Calvin



tobias
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Re: Modelling and Control of Crazyflie

Post by tobias » Thu Mar 05, 2020 10:07 am

First thing there is a paper about the modeling of the crazyflie in the bottom of the "Publications involving Crazyflie 2.X" here. You will find a lot of details there and it is still true for the 2.1.

As for controlling individual speed of the motors this is possible but maybe not the way you want to do it. If you want to run the lowest level, rate controller, on a PC instead the latency becomes a problem. I think the quickest round-trip time currently achieved is around 4ms and then the communication has to be changed a bit to minimize latency. Maybe you can share a bit more what you want to achieve so it will be easier for us to guide you?

Calvin Chua
Beginner
Posts: 10
Joined: Sun Mar 01, 2020 1:28 am

Re: Modelling and Control of Crazyflie

Post by Calvin Chua » Thu Mar 05, 2020 10:29 am

Hi Tobias,

Thanks for your reply. At the moment, I am planning to implement the control of aggresive maneuver using Crazyflie, which propably needs to control the speed of motors independently to achieve the required flying pattern.

tobias
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Location: Sweden

Re: Modelling and Control of Crazyflie

Post by tobias » Thu Mar 05, 2020 2:26 pm

Then I think you want to control the rate (rotation speed) and not the motors directly. Unfortunately this has not yet been implemented in the crazyflie firmware or lib. It should be part of the commander and I suggest you create a issue in the crazyflie-lib-python repo to suggest to add it. If you have the possibility please give it a try yourself. That would be the quickest way to get it done.

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