Motors not spinning at low throttle

Posted by Rayleigh on September 26, 2015 at 9:39am

Hi, guys

I am having this problem when building my quadcopter. Three motors don't spin until throttle reaches 16% of full throttle. Only one of them is working fine. But once they are all spinning, it seems they are at the same speed.

The motors I use are Turnigy D2836/8 1100kv. The esc are Turnigy Multistar 30A Slim V2 ESC. I am using a 3s lipo battery and a arduino mega adk to control the motors.

It is very weird and I didn't see similar problems posted. Do you guys know how I can fix it?

Thanks

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Replies

  • LAIC September 29, 2015 at 12:39am

    had the same phenomena.

    do a total erase of the APM to get rid of not firmware matching parameters
    • Rayleigh > LAIC September 29, 2015 at 8:40am

      Thanks for reply. I am not using APM though. But I think re-calibrate the ESC might help. 

  • Wijoyo Utomo September 26, 2015 at 10:42am

    Have you calibrated your ESC? Check the manual of the ESC, there must be instruction how to calibrate the ESC.

    • Rayleigh > Wijoyo Utomo September 26, 2015 at 11:23am

      I followed the link: https://dronesandrovs.wordpress.com/2012/11/24/how-to-control-a-bru... to do the calibration. But I can't find the manual of Turnigy Multistar 30A Slim V2 ESC.

      How to control a brushless motor through a ESC with Arduino
      Electronic speed control (most commonly known as ESC) are nasty beasts: not from the controlling software point of view but for the way they need to…
    • Wijoyo Utomo > Rayleigh September 26, 2015 at 11:29am

      I am not sure if the arduino really emits the correct PWM signal as your transmitter, but if I were you, I would do it from the actual transmitter that I am going to fly the uav with. 

    • Rayleigh > Wijoyo Utomo September 26, 2015 at 1:54pm

      Thank you very much. Well, the PWM signal is generated by the arduino mega adk in my uav, which I think is very similar to the arduino uno. But I think I will use the arduino mega adk to redo the calibration in case something is wrong.

  • Artem September 26, 2015 at 10:24am

     did you  Read WIKI? 

    • Rayleigh > Artem September 26, 2015 at 11:13am

      Thanks for your reply. My project is built on top of the andro-copter project of Romain Baud (http://diydrones.com/profiles/blogs/androcopter-use-you-smartphone-...). So I use a different way to do the calibration as in https://dronesandrovs.wordpress.com/2012/11/24/how-to-control-a-bru.... My esc calibration is done using an arduino uno and a potentiometer. Is this a right way to do the calibration? I mean during the calibration, everything seems to work fine.

    • James Lummel > Rayleigh September 26, 2015 at 5:31pm

      The calibration needs to be done with the transmitter as the PWM signals will likely vary from what the arduino uno and potentiometer is putting out.

      And while calibrating with the arduino uno and potentiometer will make the set points on the ESCs all the same, those set points may be higher or lower than what the transmitter is sending and you would get a problem such as you are experiencing as a result.

      Redo the calibration either thru the flight controller with the transmitter as per the videos on YouTube and the Wiki, or hook the throttle channel from the receiver directly to the ESCs (all together or one at a time) and do the calibration procedure so each ESC is set to the transmitter's set point and not some arbitrary arduino uno and potentiometer set point.

      Remember the purpose of calibrating the ESCs is twofold. First to ensure that all the motors engage simultaneously (which you DID accomplish with the method you used). Secondly, and just as importantly, it's to set the range of the throttle so that the ESCs can respond properly to high and low throttle positions and everything in-between (which can ONLY be done with by using the transmitter to calibrate).

    • Rayleigh > James Lummel September 26, 2015 at 6:07pm

      Wow! That is very detailed. Thanks very much. I think I will redo the calibration. 

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