Patent ID: 8510069

Claim:
A feedback apparatus for controlling a servo motor, comprising at least one rotary angle sensor and at least one rotary speed sensor, wherein the rotary angle sensor supplies a rotary angle measured value to a computer, wherein the rotary speed sensor supplies a rotary speed measured value to the computer, wherein in the computer the rotary speed measured value is integrated to form reference rotary angles, wherein the reference rotary angles are compared with the rotary angle measured values calculate rotary angle correction values, wherein the rotary angle measured values are calibrated using the rotary angle correction values, wherein the computer provides actual rotary angle values and/or actual rotary speed values for control purposes, wherein at high rotary speeds, the actual rotary speed values are the calibrated measured rotary angle values, and at low rotary speeds, the actual rotary speed values are the rotary angle measurements interpolated according to the integrated rotary speed measurements, and wherein at high rotary speeds, the actual rotary speed values are the calibrated rotary angle measurements differentiated with respect to time, and at low rotary speeds, the actual rotary speed values are the measured rotary speed values.