Machine tool and control method therefor

摘要

A machine tool according to an embodiment includes a drive mechanism configured to move a control target; a motor configured to operate the drive mechanism; a first encoder configured to detect a position of the control target; a second encoder configured to detect a position of the motor; a servo control unit configured to control the motor; and a numerical control unit configured to receive or calculate an error between the position of the control target obtained from a detection result of the first encoder and a position of the control target obtained from a detection result of the second encoder from the servo control unit, and to estimate a transmission error of the drive mechanism based on a change amount of the error between before and after inversion of a moving direction of the control target.

主权项

1. A machine tool comprising:
a drive mechanism configured to move a control target; a motor configured to operate the drive mechanism; a first encoder configured to detect a position of the control target; a second encoder configured to detect a position of the motor; a servo control unit configured to control the motor; and a numerical control unit configured to receive or calculate an error between the position of the control target obtained from a detection result of the first encoder and a position of the control target obtained from a detection result of the second encoder from the servo control unit, and to estimate a transmission error of the drive mechanism based on a change amount of the error between before and after inversion of a moving direction of the control target, wherein the numerical control unit is configured to: receive or calculate a first error of the drive mechanism from the servo control unit, the first error being based on the position of the control target obtained from the detection result of the first encoder and the position of the control target obtained from the detection result of the second encoder before the inversion of the moving direction of the control target, receive or calculate a second error of the drive mechanism from the servo control unit, the second error being based on the position of the control target obtained from the detection result of the first encoder and the position of the control target obtained from the detection result of the second encoder after the inversion of the moving direction of the control target, and estimate a difference between the first error and the second error as the transmission error of the drive mechanism, or calculate a difference between the first error and the second error a plurality of times to obtain a plurality of differences and estimate an average value of the differences as the transmission error of the drive mechanism.