| 摘要 |
PURPOSE:To shorten the machining time and improve accuracy by feeding back the difference of outputs of encoders detecting the rotation angle position of the output shaft of a servo motor and the position of a movable member or the difference of these time derivative values for correction control. CONSTITUTION:Whenever a motor 4 is driven, the rotation angle position of its output shaft is detected, and detected pulses are fed to a time difference detecting counter 15. Whenever a cutter feed bar 3 is shifted, the position of the feed bar 3 is detected by a reading head 13 and is fed to a detected pulses time difference detecting counter 15. The rotation angle position of the output shaft of a motor 4 and the deviation until the feed bar 3 is actually shifted are detected by the counter, and the time difference signal detected by the counter 15 is fed to the control circuit 16A of a drive control unit 16, the control signal fed to a PWM circuit 16B from an NC 17 is changed and controlled by the control circuit 16A in response to the deviation, and the drive voltage or current fed to the motor 4 is controlled. Accordingly, the deviation is kept constant, and a machining feed is performed at a speed adequate to the machining load.
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