Position feedback control system for a numerically controlled machine tool

摘要

A feedback position control system and method of extracting feedback phase or position information therefrom. A resolver or similar device such as an inductosyn is connected to each movable member of a machine tool such that the phase of the resolver output signal is indicative of the displacement of each movable member about its respective axis. The stator windings of the resolver are excited with reference and quadrature signals to generate a periodically varying output signal. The zero crossings of the output signal are monitored and the digital count in a reference counter (C.sub.A and C.sub.B) corresponding to the times of zero crossing are stored. The scaled sum of the counts C.sub.A and C.sub. B is determinative of the phase of the output signal relative to the reference signal.