Servo control device reducing deflection of front end point of machine

A servo control device which comprises a position control unit and a speed control unit and which controls the position and speed of a motor to control a front end point of a machine of a machine tool, the control device comprising:

• a position detecting unit configured to detect a position of a driven member which is driven by the motor or the motor;
• a first position error calculating unit configured to calculate a first position error on the basis of a position command to a motor and position feedback from said position detecting unit;
• a torsion estimating unit configured to estimate an amount of torsion of the front end point of the machine;
• a second position error calculating unit configured to add said first position error and estimated amount of torsion to calculate a second position error;
• a coefficient adapting unit configured to determine a coefficient of feedforward control so as to minimize said second position error;
• and
• a higher order feedforward control unit configured to perform the feedforward control by using said determined coefficient and the position command to the motor.