Control device for machine tool
Provided is a control device for a machine tool that machines a workpiece by vibration-controlling a control shaft, wherein shaking of the machine tool as a whole is reliably suppressed. This control device for a machine tool includes: a vibration condition setting unit that sets a vibration condition including at least one of a frequency parameter comprising a vibration frequency or a vibration frequency multiple, an amplitude parameter comprising a vibration amplitude or a vibration amplitude multiple, and a vibration direction; a vibration upper limit setting unit that sets, in accordance with one or both of the vibration frequency and the vibration direction, an upper limit value of the vibration parameter that is determined by the vibration condition and includes at least one of the vibration frequency, the vibration amplitude, a vibration speed, a vibration acceleration, and a vibration jerk; a vibration condition limiting unit that limits, on the basis of the upper limit value of the vibration parameter, the vibration condition set by the vibration condition setting unit; and a vibration control unit that vibration-controls a control shaft on the basis of the vibration condition limited by the vibration condition limiting unit.
1 . A control device for a machine tool that machines a workpiece while vibrating a tool and the workpiece relative to each other, the device comprising:
a vibration condition setting unit that sets a vibration condition including at least one of a frequency parameter consisting of a vibration frequency or a vibration frequency multiplying factor, an amplitude parameter consisting of a vibration amplitude or a vibration amplitude multiplying factor, or a vibration direction;
a vibration upper limit setting unit that sets an upper limit value of a vibration parameter, which includes at least one of a vibration frequency, a vibration amplitude, a vibration velocity, a vibration acceleration, or a vibration jerk, which are determined by the vibration condition, based on one or both of the vibration frequency and the vibration direction, such that shaking caused in an entirety of the machine tool is suppressed;
a vibration condition restricting unit that restricts the vibration condition set by the vibration condition setting unit, based on the upper limit value of the vibration parameter; and
a vibration control unit that executes vibration control of a control shaft, based on the vibration condition restricted by the vibration condition restricting unit.
2 . The control device for a machine tool according to claim 1 , wherein the vibration upper limit setting unit sets the upper limit value of the vibration parameter to decrease stepwise or continuously as the vibration frequency increases.
3 . The control device for a machine tool according to claim 1 , wherein the vibration upper limit setting unit sets the upper limit value of the vibration parameter to different values when the vibration direction is parallel or non-parallel to the drive direction of each control shaft.
4 . The control device for a machine tool according to claim 1 , wherein the vibration upper limit setting unit sets the upper limit value of the vibration parameter to decrease or increase stepwise or continuously as the tilt of the vibration direction relative to the central axis direction of the workpiece increases.
5 . The control device for a machine tool according to claim 1 , wherein, when the vibration frequency corresponds to a resonance frequency specific to the machine tool, the vibration upper limit setting unit sets the upper limit value of the vibration parameter to a smaller value than in cases of other frequencies.
6 . The control device for a machine tool according to claim 1 , wherein the vibration condition restricting unit restricts the vibration condition set by the vibration condition setting unit so as not to exceed the upper limit value of the vibration parameter.