
15.ACCURACY COMPENSATION FUNCTION NC FUNCTIONS B-63782EN/01
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15.10 THREE-DIMENSIONAL ERROR COMPENSATION
In ordinary pitch error compensation, compensation is applied to a
specified compensation axis (single axis) using the position
information for that axis. For example, pitch error compensation is
applied to the X-axis using the position information for the X-axis.
Three-dimensional error compensation is a function that adjusts the
current position by calculating compensation data (for three axes) from
the compensation amounts at surrounding compensation points (eight
points) on the basis of the interior division ratio in the compensation
area (rectangular parallelepiped) containing the current position on up
to three compensation axes.
- Calculation of compensation
P1
P2
P3P4
P5 P6
P7P8
x
y
z
P
Fig. 15.10 (a) Compensation Calculation Method
Let three compensation axes be X, Y, and Z (three basic axes) and the
coordinates of the current position be P (Px, Py, Pz). Consider a
compensation space (rectangular parallelepiped) containing P. Let its
vertexes be P1, P2, ..., and P8 and the compensation values for the
individual axes at the individual vertexes be Cnx, Cny, and CNz (where
n is a number between 1 and 8).
Let the interior division ratio on the X-axis at P be Cx. Here, Cx is
standardized in the range of 0 to 1 as follows:
yzxxCxyzxC
zyxxCzyxxC
zyxxCzxyxC
zyxxCzyxxCCx
)1(87
)1(6)1)(1(5
)1()1(4)1(3
)1)(1(2)1)(1)(1(1
−⋅+⋅+
−⋅+−−⋅+
−−⋅+−⋅+
−−⋅+−−−⋅=
The interior division ratios on the Y- and Z-axes are determined in the
same way.