ABOUT DRONE MOTOR KV

[laoadam]

Hi,

I am a beginner of Drone, and built one followed a project which used : 4 x 1000kV motor / 10x4.5 props / ESC combo.

I used : 4 x 2300kV motor / 8x4.5 props / ESC combo

every thing else same.

But my drone doesn't fly, it tilt, no take off even move the control lever to end.

Need help please.

Thanks

Adam

 

[HighTechPauper]

Those props are pretty big for 2300kv motors, but still it should lift off the ground even if it does not fly well, are you sure you have the motor rotation directions correct and the props are on correctly? Do the motors spin like in the picture below?

 

[laoadam]

Those props are pretty big for 2300kv motors, but still it should lift off the ground even if it does not fly well, are you sure you have the motor rotation directions correct and the props are on correctly? Do the motors spin like in the picture below?

View attachment 4751

Thank you.
Yes, I did check all motors direction and the props mounting.
I guess it is the gyro, the test code that ignored gyro can fly the drone, but the control code which take care of the gyro and to do the balance can't fly even the control rod goes to end.
Best

 

[HighTechPauper]

Interesting, so what flight control software are you running?

 

[laoadam]

Interesting, so what flight control software are you running?

my project is based on the: http://www.brokking.net/ymfc-al_main.html
and I used the code there.
The setup code can fly the drone up, the controller code doesn't.
Best

 

[laoadam]

I measured the ESC pulse during drone motor running, the front L/R = 1200, and rear L/R 740 ? why such big gap?
what's the principle of four motor's control? 4 run at same speed ?
Best

 

[HighTechPauper]

No, the 4 motors will not run at the same speed, each will be controlled by the FC to keep the quad attitude constant in relation to the radio inputs. So that means that depending on center of gravity the motors will need to work at different speeds most of the time to keep the quads attitude, so some will spin slower and some will spin faster. As far as measuring pulses from the ESC's, I would guess that the front motors are being told to spin faster and the rear motors told to spin slower because the quad thinks the front is too low and the rear is too high in relation to what it believes the quads orientation is. This is just a guess based on a PWM signal.

 

[laoadam]

No, the 4 motors will not run at the same speed, each will be controlled by the FC to keep the quad attitude constant in relation to the radio inputs. So that means that depending on center of gravity the motors will need to work at different speeds most of the time to keep the quads attitude, so some will spin slower and some will spin faster. As far as measuring pulses from the ESC's, I would guess that the front motors are being told to spin faster and the rear motors told to spin slower because the quad thinks the front is too low and the rear is too high in relation to what it believes the quads orientation is. This is just a guess based on a PWM signal.

Thanks.
The measurements I post above was done when push the pitch rod only, I mean I just let it go straight up, and the drone is assembled quite balanced and stand on the floor.
I was expect the 4 motors should run same RPM? or it will flip off, in fact it did flip back to front. don't know why?
the following code is for the drone straight up take off (if i'm not wrong), I don't know why?

if (start == 2){ //The motors are started.
if (throttle > 1800) throttle = 1800; //We need some room to keep full control at full throttle.
esc_1 = throttle - pid_output_pitch + pid_output_roll - pid_output_yaw; //Calculate the pulse for esc 1 (front-right - CCW)
esc_2 = throttle + pid_output_pitch + pid_output_roll + pid_output_yaw; //Calculate the pulse for esc 2 (rear-right - CW)
esc_3 = throttle + pid_output_pitch - pid_output_roll - pid_output_yaw; //Calculate the pulse for esc 3 (rear-left - CCW)
esc_4 = throttle - pid_output_pitch - pid_output_roll + pid_output_yaw; //Calculate the pulse for esc 4 (front-left - CW)

Best

 

[HighTechPauper]

I am not sure that the flight control software you are using can compare to very well developed code such as Betaflight, I think that what you are using will be inferior to something like this, and I think the performance will also be inferior. Betaflight has been being developed and perfected for many years through continuous improvement. The lines of code you list seem simplistic but probably will work if the PID values are working optimally. I don't think I would worry about pulse width or pulse position, it is all happening too fast to try and read too much into it, if it is correct the quad will work, if there is a bad input or sensor then it will not work well. Here we mostly stick with well developed hardware and software so our flight experience is pretty good.