NURBS curve fitting method based on improved second-order oscillation PSO algorithm

Abstract

The invention discloses an NURBS curve fitting method based on an improved second-order oscillation PSO algorithm. The NURBS curve fitting method comprises the steps of obtaining discrete data points to be fitted; performing parameterization processing on the discrete data points; taking an inflection point and a curvature extreme point as selection standards, screening out points which can best reflect the shape and characteristics of the discrete data points from the discrete data points, and recording the points as characteristic points; obtaining a node vector of the NURBS curve; approaching the feature points under a least square method, and performing back calculation to obtain an initial control point; constructing an initial population of the initial control point coordinates and performing population initialization; establishing an effective fitness function; optimizing the position of the initial control point by using an improved second-order oscillation PSO algorithm to obtain an optimized optimal control point; and according to the node vector and the optimized optimal control point, performing fitting to generate an NURBS curve. According to the method, the accuracy and reliability of NURBS curve fitting are improved.

Description

technical field [0001] The invention relates to the fields of reverse engineering and computer-aided design, in particular to a NURBS curve fitting method based on an improved second-order oscillation PSO algorithm. Background technique [0002] In reverse engineering, it is often necessary to rely on a large amount of point cloud data to reconstruct the physical model, but the error generated in the actual measurement process is relatively large, so the operator generally uses interpolation or approximation methods to reduce the error as much as possible, so as to obtain the accuracy higher curve. During the interpolation process, the curve can accurately pass through each discrete data point, so the amount of data will also become large, increasing the burden of data transmission and processing, and the efficiency is not high. In contrast, the approximate fitting method can not only adjust the fitting accuracy, but also compress the amount of data, and is widely used in a...

AI Technical Summary

Problems solved by technology

At present, many advanced CNC companies abroad, such as FANUC, SIEMENS, MITSUBISHI, etc., have mature and standardized NURBS curve fitting, planning and interpolation methods, but these technologies are in a confidential state and are not open to users.

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