Originally Posted by
boonie
Yes, it looks like the servo drives will be implementing localized closed loop control over their respective axes (for their individual steps). Since the axes are not linked I believe they can come out of sync, leading to elliptical error when cutting circles. I'd think that the way to correct this would be to collect all the F/B in the controller and compare the two axes doing the circle to each other and the circle vector... or go really slow, in tiny steps to insure that there is no overshoot/fall-behind... which is how you'd run a stepper motor system. (?)
From the controller's point of view, isn't the only difference between a stepper and servo system using this style of servo drive that the servo drive can notify the controller (through the err/res channel) when the servo misses a "step" (or several...) and is no longer on course, allowing for the controller to kill the program?
----question:
Am I thinking this through correctly?