Numerical controller having command path compression function

A numerical controller that controls a machine tool composed of a plurality of driving axes including at least two straight-line axes that perform processing on a workpiece attached to a table, the numerical controller comprising:

• a command reading unit configured to read a command path being a sequence of a plurality of command points and a relative feed speed command of the workpiece and a tool;
• a subsequence extraction unit configured to extract a subsequence from the sequence of command points to divide the sequence of command points in a manner such that the same path may be created regardless of whether the command points read are extracted by the command reading unit from a commanded direction or from a direction reverse to the commanded direction;
• a point sequence compression unit configured to create a compressed path approximated by a straight line or a curve of which the distance from each command point in the extracted subsequence is within a preset tolerance in a manner such that the compressed path may be approximated by the same straight line or curve regardless of whether the compressed path is created from the extracted subsequence in a commanded direction or in a direction reverse to the commanded direction;
• an interpolation unit configured to obtain the position of each axis for each interpolation cycle in a manner such that the tool may move at the commanded relative feed speed on the path compressed by the point sequence compression unit;
• and
• a motor driving unit configured to drive a motor of each axis to move to the position of each axis obtained by the interpolation unit.