Patent attributes
A numerical control apparatus of a machine tool that performs tapping, includes a numerical control, an acceleration learning block, an acceleration/deceleration processing unit that applies an acceleration/deceleration process to the command acceleration and the position command value to calculate a post-acceleration/deceleration position command value, a position control unit that calculates a speed command value based on the post-acceleration/deceleration position command value, a speed/torque control unit that calculates a motor torque command value from the speed command value, and a current control unit that calculates a motor current value of a spindle motor from the motor torque command value. The acceleration learning block outputs, as the command acceleration A, an initial command acceleration A[0] which is smaller than the calculated command acceleration, in accordance with a state quantity of the spindle motor, to the acceleration/deceleration processing unit.
