Patent ID: 6590358
Filing Date: 2003-07-08
Classification: G05B,H02P

Abstract:
A servo control apparatus of a servo system using a servomotor for controlling positions of feed shafts of a machine tool and a drive, wherein a disturbance having a frequency proportional to a rotation speed of the servomotor is loaded on the servo system containing a driven machine, said servo control apparatus comprising:detection means for detecting a position and the rotation speed of the servomotor, a position control section for generating a speed command based on a difference between a position command and a position feedback signal output by said detection means, a speed control section for generating a current command based on a difference between the speed command and a speed feedback signal, a current control section for controlling an electric current allowed to flow into the servomotor based on the current command, and a periodical disturbance estimater for inputting information of a proportionality constant between the disturbance frequency and the servomotor rotation speed, servomotor position information, and a difference signal between the speed command and the speed feedback signal, estimating magnitudes of a sine-wave component and a cosine-wave component at the frequency of the disturbance in real time during normal servomotor driving, and combining the sine-wave component and the cosine-wave component at the frequency of the disturbance estimated to generate a correction value, wherein the correction value is added to the current command in real time during the normal servomotor driving.