US Patent No. 9,377,772


Patent No. 9,377,772
Issue Date June 28, 2016
Title Numerical Controller Including Corner Multiple Curves Inserting Unit
Inventorship Naoya Koide, Minamitsuru-gun (JP)
Assignee FANUC Corporation, Minamitsuru-gun, Yamanashi (JP)

Claim of US Patent No. 9,377,772

1. A numerical controller configured to control a machine tool for machining a workpiece on a basis of a machining program
composed of a plurality of blocks, the numerical controller comprising: a processor and a memory, the processor configured
to execute:
a corner multiple curves inserting unit which inserts, between consecutive two blocks in the machining program, three cubic
polynomial curves in which a position, a direction and a curvature of each one of the three cubic polynomial curves are continuous
and distances from the two blocks are within a prescribed allowable tolerance, if the consecutive two blocks are linear blocks
and equal to or above a distance d from a vertex of a corner to a starting position of the curves and from the vertex of the
corner to an ending position of the curves,

wherein, the three cubic polynomial curves to be inserted are determined by evaluating the distance d and a magnitude |v|
of first-derivation vectors vs and ve at both ends of the curve, from an angle ? of the corner and an allowable tolerance /at the corner, on a basis of a relationship
among ?, d, and /which are previously evaluated in the three cubic polynomial curves,

wherein a relationship among ?, d, and l are previously evaluated so as to reduce a curvature and a curvature change in the
three cubic polynomial curves, and

wherein if a path of a tool center point on the workpiece is commanded by a machining program in a five-axis machine tool
having three linear axes and two rotational axes for controlling tool directions with respect to the workpiece, three cubic
polynomial curves are inserted into the path of the tool center point.