Position control apparatus

Abstract

A position control apparatus includes a reverse displacement calculation unit configured to calculate a reverse displacement that represents an amount of movement made from a preceding reverse point to a current reverse point by an axis that performs a reversing motion; a reversing-time segmenting number number of consecutive occurrences of reversing motions calculation unit configured to compare the reverse displacement to a predetermined value, and, when the reverse displacement is less than the predetermined value, increase a value of a reversing-time segmenting number of consecutive occurrences of reversing motions, which is a coefficient indicating a number of segments per unit time during a reversing motion, and, when the reverse displacement is greater than or equal to the predetermined value, decrease the value of the reversing-time segmenting number number of consecutive occurrences of reversing motions; and a quadrant inversion compensation unit configured to automatically adjust a quadrant inversion compensation amount according to the reversing-time segmenting number number of consecutive occurrences of reversing motions and perform the quadrant inversion compensation based on the automatically adjusted compensation amount.

What is claimed is: 
     
       1. A position control apparatus that performs quadrant inversion compensation when an axial moving direction of a machine is reversed, comprising:
 a control unit comprising: a reverse displacement calculation unit configured to calculate a reverse displacement that represents an amount of movement made from a preceding reverse point to a current reverse point by an axis that performs a reversing motion;   a reversing-time segmenting number number of consecutive occurrences of reversing motions calculation unit configured to compare the reverse displacement to a predetermined value, and, when the reverse displacement is less than the predetermined value, increase a value of a reversing-time segmenting number of consecutive occurrences of reversing motions, which is a coefficient indicating a number of segments per unit time during a reversing motion, and, when the reverse displacement is greater than or equal to the predetermined value, decrease the value of the reversing-time segmenting number number of consecutive occurrences of reversing motions; and   a quadrant inversion compensation unit configured to automatically adjust a quadrant inversion compensation amount according to the reversing-time segmenting number number of consecutive occurrences of reversing motions, and perform the quadrant inversion compensation based on the automatically adjusted compensation amount.   
 
     
     
       2. A method for performing quadrant inversion compensation in a machine tool for processing a workpiece, the method comprising:
 calculating, by a control unit (MCU), a reverse displacement that represents an amount of movement made from a preceding reverse point to a current reverse point by an axis of the machine tool that performs a reversing motion;   comparing, by the MCU, the reverse displacement to a predetermined value, and, when the reverse displacement is less than the predetermined value, increasing a value of a number of consecutive occurrences of reversing motions, and, when the reverse displacement is greater than or equal to the predetermined value, decreasing the value of the number of consecutive occurrences of reversing motions;   automatically adjusting, by the MCU, a quadrant inversion compensation amount according to the number of consecutive occurrences of reversing motions; and   performing, by the MCU, the quadrant inversion compensation based on the automatically adjusted compensation amount.