Servo control apparatus

Abstract

A sensor array produces two sinusoidal position signals which vary in phase by 90.degree. in response to rotation of a servo motor shaft. These position signals are inverted and the position signals and their inversions are commutated to produce a velocity signal. A position error signal is generated which indicates the difference between the actual motor shaft position and the command position. A reference signal is voltage divided in accordance with the position error signal to produce a velocity command signal which is compared with the velocity signal to produce a motor drive signal. The position signals and their inversions are half wave rectified, integrated and summed to produce the reference signal as a varying D. C. signal, the magnitude of which corresponds to the amplitude of the position signals and compensates for variations in said amplitude caused by high frequency attenuation in the sensor array and like phenomenon.

Dependencies are inferred from the claim text.