A-78640E
Sheet
Title
Draw
No.
04 Feb.08.’03 Part of (4) is added or modified. Addition of 2.16.5
03 Jul.02.’02 A. Fukumoto Part of (3) is added or modified. T.Endo
02 May.13.’02 A. Fukumoto Addition of Tool Radius control for 5-axis machining etc T.Endo
Ed. Date Design Description
Date Jan.25.’02 Desig. A.Fukumoto Apprv. T.Endo
FANUC Series 16i /18i -TB
Specifications of AI High-Precision Contour Control /
I Nano High-Precision Contour control
26/190
2.14.5 NURBS curve
Using these variables:
parameter, Spline
( ],...,,[ vector Knot
) ( Knot:
Weight
point Control
Rank
1+
:
)
:
:
:
t
knm
w
k
xxx
xxx
m10
iii
i
i
+=
≤
P
The spline basis function N can be expressed with the de Boor-Cox recursive
formula, as indicated below:
)
()
i
ii
i
i
N
t
t
tt
xx
x
x
,
()
,
1
1
1
1
0
=
≤≤
<<
⎧
⎨
⎪
⎩
⎪
+
+
ik
iik
ik i
ik i k
ik i
N
t
t
xN
t
xx
x
t
N
t
xx
,
,,
()
( ) () ( ) ()
=
−
−
+
−
−
−
+−
++−
++
1
1
11
1
The NURBS curve P(t) of interpolation can be expressed as follows:
∑
∑
=
=
=
n
i
iki
n
i
i
iki
w
t
N
w
t
N
t
0
,
0
,
)(
)(
)(
P
P
)(
0
m
t ≤≤
2.14.6 Limitations
• Manual absolute
If manual intervention is attempted in the manual absolute ON, P/S alarm 5118
occurs.
• Cutter compensation
The cutter compensation cannot be simultaneously executed. NURBS
interpolation can only be specified after the cutter compensation has been
canceled.
• Reset
A reset during NURBS interpolation results in the clear state. The modal code of
group 1 enters the state specified in the G01 bit (bit 0 of parameter 3402).