Patent ID: 8093856

Claim:
A position control apparatus that is usable in a case where a motor drives a movable portion of a numerically controlled machine to change a relative positional relationship between two control objects provided on the numerically controlled machine, wherein the position control apparatus controls the position of the movable portion based on a position command value of the motor that is input from a host apparatus, the position control apparatus comprising: a machine deflection amount estimation unit that calculates a machine deflection amount estimation value representing a relative displacement amount between the two control objects that may be caused by a deflection of a structural member intervening between the two control objects based on information indicating a posture of the intervening structural member and information indicating a driving acceleration of the movable portion; a machine deflection compensation amount calculation unit that calculates a machine deflection position compensation value based on the machine deflection amount estimation value for compensating at least a positional deviation that may be caused by a deflection of the intervening structural member; and a command value calculation unit that generates a new position command value for the control by adding the machine deflection position compensation value to the position command value.