Machine tool controller

A machine tool controller that relatively moves a workplace or a tool while rotating the workpiece to perform machining of the workpiece, the machine tool controller comprising:

• a servo control unit that generates a positional error based on a difference between a position command for moving the workplace or the tool so that the workpiece is machined in a desired shape and a present position of the workplace or the tool and generates a drive command for a driving unit that moves the workpiece or the tool on the basis of the positional error;
• and
• a displacement meter that measures a machining surface displacement amount of the workpiece for each rotation angle of the workpiece, wherein
• the servo control unit includes:
• a compensation amount calculating unit that calculates a shape error of the workpiece with respect to the desired shape for each rotation angle of the workpiece on the basis of the machining surface displacement amount measured by the displacement meter and obtains a compensation amount of the positional error on the basis of the calculated shape error of the workpiece;
• and
• a first compensation unit that compensates the positional error for each rotation angle of the workpiece on the basis of the compensation amount calculated by the compensation amount calculating unit.