Motor Control

Firmware/software/electronics/mechanics
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thediscomole
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Joined: Fri Apr 04, 2014 11:02 am

Motor Control

Post by thediscomole » Fri Apr 04, 2014 11:12 am

Hello,

I recently acquired a crazyflie 10DOF and will receive all the parts etc in about a month. Today I was skimming through some dev topics and found that many of you were saying that the most low level access to motor control goes through pitch roll yaw. Is this correct? Am I not able to individually control the 4 motors?

Though the pitch roll yaw control is not a deal breaker for my development plan I would prefer the more crude control type. Since I am in the middle of coursework and exams I haven't had the time to inspect the source. Hence if someone could tell me how difficult it would be to change the existing code to individual motor control that would be great.

EDIT: one more question. I also saw a topic which described low data transmission rates for automation through the crazyradio. If you could give me a rough estimate of how many instructions(like sizeof( 2 ints ) hue per instruction) per sec i can give the Crazyflie through telemetry whilst sending the sensory information to my laptop as it is being recorded that would help me in pre planning greatly.

Thank you for your time
Last edited by thediscomole on Fri Apr 04, 2014 11:26 am, edited 1 time in total.



DerShu
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Posts: 23
Joined: Thu Nov 14, 2013 3:01 pm
Location: Bavaria - Germany

Re: Motor Control

Post by DerShu » Fri Apr 04, 2014 11:23 am

thediscomole wrote:Hello,

I recently acquired a crazyflie 10DOF and will receive all the parts etc in about a month. Today I was skimming through some dev topics and found that many of you were saying that the most low level access to motor control goes through pitch roll yaw. Is this correct? Am I not able to individually control the 4 motors?

Though the pitch roll yaw control is not a deal breaker for my development plan I would prefer the more crude control type. Since I am in the middle of coursework and exams I haven't had the time to inspect the source. Hence if someone could tell me how difficult it would be to change the existing code to individual motor control that would be great.
Marcus explained that a couple of weeks ago at this link.
http://forum.bitcraze.se/viewtopic.php?f=6&t=808

After reading his explanation, it looks very easy to do the code change, BUT extremely difficult to get it work for safe flight.

thediscomole
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Joined: Fri Apr 04, 2014 11:02 am

Re: Motor Control

Post by thediscomole » Fri Apr 04, 2014 11:27 am

wow thnx for the quick reply, if you could help me with my second question you'll be my hero :D

arnaud
Bitcraze
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Joined: Tue Feb 06, 2007 12:36 pm

Re: Motor Control

Post by arnaud » Mon Apr 07, 2014 12:35 pm

Hi,

The current Crazyradio implementation permits to send and receive up to 500~1000 packets per seconds, each packets containing up to 32 bytes (30 bytes if you stick with our log implementation). The radio in itself has been measured by master thesis student (Measurements are in there report: http://www.bitcraze.se/2012/06/camera-a ... er-thesis/) to be able to transmit up to 400KBit/sec with firmware dongle modification (the current hard limitation is in the way the USB protocol is implemented. Though most of the time the bandwidth will be limited by the quality of the radio link).

These number are true only when the radio link is perfect, with no interference and with a free USB bus. There is no way to guarantee latency and/or bandwidth on radio.

I hope this answer your question.

thediscomole
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Joined: Fri Apr 04, 2014 11:02 am

Re: Motor Control

Post by thediscomole » Fri Apr 11, 2014 2:52 pm

Yes thank you very much!

Much appreciated everyone

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