Numerical control apparatus having a fine line differentiation method and spline interpolation function of the curve

摘要

PROBLEM TO BE SOLVED: To prevent a spline curve passing through the point sequence from generating a large error with an original curve at the time of finely segmenting the curve and generating the point sequence by evaluating the error of a cubic spline curve and reconstituting the point sequence by adding a passing point inside a section in the case that the error exceeds an allowable value. ;SOLUTION: The curve is approximated fine segment data by the allowable error ε (S101). Then, the spline curve is generated from the (n) pieces of the passing points P₁, P₂,...P_n-1 (S102). Then, a specified point P_j is initialized (S103) and whether or not the inflection point of the curve is provided inside the section is evaluated in the respective sections of the spline (104). Then, in the case of judging that the inflection point is provided inside the section (S105), the error in the respective sections P_j-P_j+1 of the cubic spline curve is evaluated (S106). Further, whether or not the obtained error d_j exceeds the allowable error ε is evaluated (S107). It is defined that the error is within the allowable value error and (S109) is advanced at the time of d_j≤ε and it is defined that it exceeds the allowable error and (S108) is advanced at the time of d_jε.;COPYRIGHT: (C)1998,JPO