Motor control device
AssigneeFanuc Corporation
InventorsYuuki Morita, Tadashi Okita
Life of this patent
Estimating the term…
Abstract
A motor control device is a motor control device which controls a spindle motor of a machine tool, the device including: a low-pass filter which averages torque command values or drive current values of the spindle motor and calculates averaged load information of the spindle motor; and a time constant calculation unit which calculates, as a time constant of the low-pass filter, a first time constant based on a cut-off frequency according to the rotation number of the spindle driven by the spindle motor, or a second time constant based on a cut-off frequency according to a value produced by multiplying a of cutting tooth number of a tool by the rotation number of the spindle.
Claims9
A motor control device for controlling a spindle motor which rotationally drives a tool or workpiece in a machine tool, the motor control device comprising:
- a first low-pass filter which averages torque command values or drive current values of the spindle motor and calculates averaged first load information of the spindle motor;
- a time constant calculation unit configured to calculate, as a time constant of the first low-pass filter, a first time constant based on a cut-off frequency according to a rotation number of a spindle driven by the spindle motor, and in a case of the spindle rotationally driving the tool, a second time constant based on a cut-off frequency according to a value produced by multiplying a number of cutting teeth of the tool by the rotation number of the spindle;
- and
- a second low-pass filter which averages the torque command values or drive current values of the spindle motor, and calculates averaged second load information of the spindle motor,
- wherein a time constant of the second low-pass filter is larger than the time constant of the first low-pass filter,
- wherein a fluctuation of the second load information of the spindle motor is smaller than a fluctuation of the first load information of the spindle motor due to the time constant of the first low-pass filter and the time constant of the second low-pass filter, and
- wherein the first load information of the spindle motor is used for controlling machining conditions of the spindle motor so as to suppress a decline in responsiveness of control of the machining conditions.
A motor control device for controlling a spindle motor which rotationally drives a tool or workpiece in a machine tool, the motor control device comprising:
- a first low-pass filter which averages torque command values or drive current values of the spindle motor and calculates averaged first load information of the spindle motor;
- a time constant calculation unit configured to calculate, as a time constant of the first low-pass filter, a first time constant based on a cut-off frequency according to a rotation number of a spindle driven by the spindle motor, and in a case of the spindle rotationally driving the tool, a second time constant based on a cut-off frequency according to a value produced by multiplying a number of cutting teeth of the tool by the rotation number of the spindle;
- and
- a second low-pass filter which averages the torque command values or drive current values of the spindle motor, and calculates averaged second load information of the spindle motor,
- wherein a time constant of the second low-pass filter is larger than the time constant of the first low-pass filter, and
- wherein the time constant calculation unit is configured to switch between setting the first time constant as the time constant of the first low-pass filter, and setting the second time constant as the time constant of the first low-pass filter, so that a magnitude of fluctuation of the first load information becomes smaller.
Dependencies are inferred from the claim text.