Jeff:
You said "closed loop back to the driver". What about the software? Does the control program need to know about a difference between commanded and actual position?
Or does the driver handle the error and the program doesn't need to know?
Having asked the question and mulled over possiblilities it occurs to me that the control program not only doesn't know about tool slippage, in most (stepper) cases it doesn't care either. It just spits out commands and assumes that they are obeyed
. It is on the operator to make sure the work piece is not a scrap piece.
Does software designed specifically for servo systems act differently?
robotic regards,
Tom