increasing frequency of Servo library

Other Hardware Motors, Mechanics, Power and CNC
1

Hello,
I'm using the servo library to control brushless dc motors for a quadcopter. my question is can I increase the frequency of the pwm used by the servo library? I found this line in Servo.cpp #define TAU_MSEC 20 which is the period of the pulse in ms.
I want to decrease this time to 1 or 2ms. has anybody tried this before? I just want to make sure.
another question, is there a limitation in using the servo library over using analog write to control motor speeds? I want the response of my motors to be as fast as possible. I heard about fast pwm but I'm not sure how to use it so thats why I'm using the servo library instead for its simpler.

any feedback will be alot appreciated :slight_smile:

2

I want to decrease this time to 1 or 2ms.

You mean you want to make the frame time the same as the control pulse width?

What frame rate do your ESCs support?

3

yes I just want to increase the frequency, maybe to 300hz or above. its written on my ESC's manual that the control frequency can be 8khz if thats what you mean

4

Have you got a link to this device?
8kHz is not standard R/C territory.

5

This is it:
http://www.emaxmodel.com/views.asp?hw_id=1305

6

The way I read it, 8kHz is the motor PWM frequency, not the control PWM frequency.

7

isn't it the same thing? and do you have any idea whether I can use analogwrite instead? analog write has a frequency of 488 hz

8

ok after some research I think I can understand the difference now between motor pwm and esc refresh rate. I just have no idea whether my ESC will be able to handle higher frequencies. anyway thanks for your help. :slight_smile:

9

A good starting point is "if it works, don't fix it"

If you find some behaviour of your ESCs that might be improved by a higher servo refresh rate let us know.

...R