US Patent No. 9,223,304

NUMERICAL CONTROLLER WITH WORKPIECE SETTING ERROR COMPENSATION UNIT FOR MULTI-AXIS MACHINE TOOL


Patent No. 9,223,304
Issue Date December 29, 2015
Title Numerical Controller With Workpiece Setting Error Compensation Unit For Multi-axis Machine Tool
Inventorship Toshiaki Otsuki, Minamitsuru-gun (JP)
Assignee FANUC Corporation, Minamitsuru-gun, Yamanashi (JP)

Claim of US Patent No. 9,223,304

1. A numerical controller for controlling a multi-axis machine tool having at least three linear axes and three rotating axes
for machining a workpiece attached to a table,
wherein the numerical controller comprises a workpiece setting error compensation unit for compensating a setting error that
arises when the workpiece is set, the workpiece setting error compensation unit including:

a tool position/direction calculation unit for calculating tool position and direction on a workpiece setting coordinate system
on the basis of commanded positions of the three linear axes and three rotating axes, wherein the workpiece setting coordinate
system is the coordinate system on which the workpiece is set;

a compensated tool position/direction calculation unit for calculating compensated tool position and direction on the basis
of the setting error amounts that are set in advance depending on the setting error, such that tool position and direction
on the workpiece setting coordinate system calculated by the tool position/direction calculation unit are maintained on the
workpiece having the setting error, and

a compensated linear/rotating axis position calculation unit for calculating compensated linear axis positions of the three
linear axes and compensated rotating axis positions of the three rotating axes from the compensated tool position and direction
calculated in the compensated tool position/direction calculation unit;

wherein the three linear axes and three rotating axes are driven on the basis of the compensated linear axis positions of
the three linear axes and compensated rotating axis positions of the three rotating axes calculated by the compensated linear/rotating
axis position calculation unit,

wherein the compensated linear/rotating axis position calculation unit determines the compensated rotating axis positions
by calculating multiple solutions for the three rotating axes from the compensated to direction calculated by the compensated
tool position/direction calculation unit and synthesizing the calculated multiple solutions.