Method for registering complex curved surface

Abstract

The invention relates to a method for registering a complex curved surface. A system in the method comprises a curved surface CAD design model, a three-coordinate measuring machine and a registering solver, wherein the curved surface CAD design model comprises geometric information of the curved surface; after the geometric information of the curved surface is extracted, a curved surface NURBS model is constructed; the three-coordinate measuring machine detects a curved surface real object prototype, and acquires measuring point data; and the registering solver registers the measurement data of the curved surface NURBS model and the curved surface real object prototype by adopting a genetic algorithm. Compared with the prior art, the method has the advantages of accurate theory model, high registering stability, good registering accuracy, capability of achieving multidimensional variable registrations, and wide application range.

Description

technical field [0001] The invention relates to the technical field of mechanical design and detection, in particular to a registration method for complex curved surfaces. Background technique [0002] Complex surface registration technology is widely used in shape error detection, multi-view point cloud relocation, reverse engineering, virtual reality and other fields. It is a prerequisite for model evaluation, error analysis, and data stitching. Since the CAD model is designed in the coordinate system of the CAD design software, and the measurement is carried out in the coordinate system of the measuring equipment, the complex surface measurement coordinate system and the design coordinate system (CAD coordinate system) are objectively independent of each other, and the measurement data There is no clear size correspondence with the CAD model, and the complex surface has no obvious reference features, the mathematical model of the complex surface is very complicated, and i...

AI Technical Summary

Problems solved by technology

Since the CAD model is designed in the coordinate system of the CAD design software, and the measurement is carried out in the coordinate system of the measuring equipment, the complex surface measurement coordinate system and the design coordinate system (CAD coordinate system) are objectively independent of each other, and the measurement data There is no clear size correspondence with the CAD model, and the complex surface has no obvious reference features, the mathematical model of the complex surface is very complicated, and it is difficult to find an accurate size correspondence between the measurement reference and the design reference of the complex surface, so the complex surface configuration Accuracy has always been the key and difficult point of the problem

If the two are not unified, it will inevitably affect the calculation results of subsequent error detection and model evaluation.

[0004] The basic principle of the least squares method is to minimize the sum of the residual squares between the two, which has the advantages of simple calculation and easy implementation, but the accuracy of the results calculated by the least squares method is not high enough, often 1.8% greater than the exact result- 30%, so it is not suitable for complex surface registration with high precision requirements

[0005] The iterative closest point method must first find two corresponding subsets between point sets and point sets, and then find the transformation matrix of the two point sets. Its algorithm is simple and its precision is high. One point set in the matching point set is a subset of another point set. Second, the relative initial positions of the two point sets are relatively high. The relative initial positions of the two point sets cannot be too different. When the positions differ greatly, it is easy to fall into a local minimum, and the direction of convergence may be uncertain

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