I've noticed some discussions that mention about the speed in hertz of the ESC and it having something to do with the ability of the quad to control it's attitude. Can someone explain to me about this? I noticed another thread about some custom made ESC's that are faster? How does this work and how does it effect the operation and can the APM benefit?
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The idea is that the faster you can update the speed of the motors, the finer control you have over the attitude of the quad. We don't send a continuous signal to the ESC, but instead vary the motor speed over a curve. It's akin to having high res graphics versus low res. Everything looks smoother with higher speed updates. The caveat is that we have to be sending the correct updates in the first place to get a better result. The assumption here is that you have sensors that are updated at least at the speed that you are sending the ESC updates, and that you have calculated the attitude correctly. And the ESCs are ultimately not going to respond faster than the components they are built with, nor will the motors angular momentums allow them to change speed at a rate faster than they're capable off.
The re-programmed ESCs is needed on some because they have low pass filters that won't take updates faster than a few 10's of hertz versus the hundreds of hertz we are trying to send. The low pass filters help to eliminate high speed pwm jitters. The assumption here is that the Atmel that we are using, with the aid of hardware clock driven PWM signals are capable of sending jitterless signals to the ESC.