Patent ID: 7433754

Claim:
A numerical controller controlling a machining apparatus having a tool machining a workpiece and servomotors driving a plurality of axes including at least two rotary axes, wherein interpolation processing is performed on a motion path of the tool commanded by a machining program and motion commands are outputted respectively for the plurality of axes based on the interpolation processing, said numerical controller comprising: analyzing means for analyzing commands of the machining program and obtaining data of a length of a circular arc, angles between postures of the tool and tangential directions of the circular arc at a start point and an end point of the circular arc, respectively, and angles between postures of the tool and normal directions of the circular arc on a plane on which the circular arc is placed at the start point and the end point of the circular arc, respectively; interpolating means for obtaining data of an interpolated position of the circular arc and a posture of the tool at the interpolated position of the circular arc at every sampling period based on the data obtained by said analyzing means; position calculating means for obtaining target positions of the plurality of axes based on the data obtained by said interpolating means; and moving means for moving the plurality of axes to the target positions obtained by said position calculating means.