I have built an Arduino DUE based quadcopter and I am using HC-12 as a transmitter and receiver between my laptop and the quadcopter. What am I doing is just send a speed value from my laptop and apply that value to all the quadcopter motors wirelessly. The problem is my quadcopter is flipping while trying to go up. Watch this video here to get an idea of what I mean. I had tried to make the quadcopter balanced and I got the same problem. By the way, I tried to change the motors and tried many ways to balance it and to make the center of gravity in the center of the quadcopter but I faced the same problem of flipping. I need to make the quadcopter go up normally without control and flipping just by giving the value of the motors speed from the laptop without RC.

Edit: Now I rebuilt it and recalibrated the ESCs after that, I got this result. My quadcopter seems to be hovering from 3 sides and the last one can't hover for the same speed. I tried to increase the speed of that motor and change the motor but I got no difference.

  • $\begingroup$ Are you using any feedback control, something like PID, and if so did you also tune them? $\endgroup$
    – fibonatic
    Oct 29 '18 at 0:58
  • $\begingroup$ you have to realize that the flipping problem has nothing to do with the center of gravity of the quadcopter ..... it has everything to do with the amount of power being fed to the rotors ..... you require a feedback loop that controls the distribution of power to the four rotors $\endgroup$
    – jsotola
    Oct 29 '18 at 1:06
  • $\begingroup$ No, I am not using any controller in this part of my work, not even PID. $\endgroup$ Oct 29 '18 at 22:45
  • $\begingroup$ I have checked the power distribution but everything seems to be normal. $\endgroup$ Oct 29 '18 at 22:48
  • $\begingroup$ Very sorry I changed the link and now it is working @Szczepan $\endgroup$ Oct 30 '18 at 10:28

Quadrocopter is nowhere near to normal RC airplane, where balancing can help a lot with stability. You'll need to utilize at least PID controller to keep your multirotor steady.

I guess you don't have much experience with quadrotors whatsoever, therefore I'd suggest you to use an integrated flight controller, i.e. this one. Mind that, when building such device, you will surely need much more knowledge and experience in electronics and software engineering to get satisfying flight results.

  • $\begingroup$ Thank you for your answer My problem now is that I am working only on the altitude of the quadcopter. I have designed a controller and its response seems to be good but it can't handle the tilting of the quadcopter because its purpose is just for the altitude. I implemented this quadcopter first by using APM 2.6 flight controller and RC FS-I6, I controlled it by the RC and everything was good but in my project, I should design my own controller for this reason I change the controller. My purpose of what am I doing is just to make the quadcopter hover normally and all at the same level. $\endgroup$ Oct 29 '18 at 23:13
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    $\begingroup$ @AwsAbdulSalam you can't only use a controller for altitude, you also need attitude control. $\endgroup$
    – fibonatic
    Oct 30 '18 at 8:27
  • $\begingroup$ @fibonatic but my work purpose now is just to make the quadcopter go up and down without any small tilting in it and without using attitude control $\endgroup$ Oct 30 '18 at 10:34
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    $\begingroup$ @AwsAbdulSalam You can't because any small perturbation, even if the drone is perfectly ballanced, will cause the thrust to also point partially in a horizontal direction and the drone will start accelerating sideways. $\endgroup$
    – fibonatic
    Oct 30 '18 at 10:40
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    $\begingroup$ Yes, you will face the same problem. Please read this article about PID in multicopters, hopefully you'll find that descriptive and helpful. $\endgroup$
    – Szczepan
    Oct 30 '18 at 11:31

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