Numerical controller having function of controlling speed by superimposed control

A numerical controller that has a first axis which is determined to be a reference axis and a second axis which is determined to be a superimposed axis different from the first axis, and performs superimposed control which superimposes a movement amount of the reference axis on a movement amount of the superimposed axis, and thereby controls the movement of the superimposed axis, comprising:

• an acceleration start time control unit which controls an acceleration start time of an axis to be accelerated in a superimposition interval in which the superimposed axis is accelerated and the reference axis thereof is decelerated;
• wherein the acceleration start time control unit comprises:
• an acceleration/deceleration combination determining portion which determines respective combinations of acceleration and deceleration of the reference axis and the superimposed axis;
• an acceleration/deceleration time comparing portion that compares a time period during which the superimposed axis is accelerated, with a time period during which the reference axis is decelerated in a case where the acceleration/deceleration combination determining portion determines that the superimposed axis is accelerated and the reference axis is decelerated;
• a speed limit excess determining portion which determines whether a moving speed of the superimposed axis exceeds a speed limit of the superimposed axis in a case where the acceleration/deceleration time comparing portion determines that the time period for deceleration is longer than the time period for acceleration;
• and
• a speed control portion which excludes the movement amount contributing to the acceleration from the movement amount of the superimposed axis in a case where the speed limit excess determining portion determines that the moving speed of the superimposed axis exceeds the speed limit of the superimposed axis.