复杂箱体的数字化测量与逆向设计

发布时间：2018-05-17 21:17

本文选题：数字化测量 + 逆向设计　；参考：《河南科技大学》2017年硕士论文

【摘要】：随着经济社会的快速发展,在制造业领域,人们对产品的外形设计、制造质量及检验精度的要求越来越高,使数字化测量与逆向设计技术在产品的生产中得到了广泛的应用。同时,数字化的测量、设计、制造之间的联系越来越紧密,它们构成了产品制造生产的闭环数字链,满足了现代制造业对系统高度集成的要求。数字化测量与逆向设计技术在保证产品质量与提高生产效率方面起着越来越重要的作用。本文研究了复杂箱体铸件的数字化测量与逆向设计的一些关键的技术:数字化测量的方法、数据处理方法、曲面重构方法与模型精度评价技术。对于数字化测量,分析了复杂箱体的内外形结构特征,采用了基于转站测量的三维激光扫描方式对箱体外表面进行了测量,获取了箱体外表面的点云数据;提出了一种基于石膏模型的箱体内腔的数字化测量方法,完成了对箱体内腔的测量,获取了箱体内腔表面的点云数据;利用了基于特征点匹配的数据融合方法完成了箱体外表面点云与内腔点云的数据融合,获得了完整的复杂箱体内外表面点云数据。在数据处理方面,分析了测量噪声点产生的原因,研究了点云的去噪与精简方法;针对复杂箱体点云数据的去噪提出了基于空间单元格的快速k邻域搜索方法,并获得了较好的噪声去除效果;分析了不同数据类型的精简处理方法,提出了将曲率采样和均匀采样相结合的混合精简方法对复杂箱体的点云数据进行了精简处理;并验证了所提出的数据去噪与精简算法的有效性且获得了良好的处理结果。在曲面重构的过程中,针对复杂箱体的曲面重构,研究了曲线拟合造型与曲面拟合造型,并对曲线、曲面光顺的方法进行了研究分析;根据复杂箱体的内外表面点云数据重构了该箱体的三维CAD模型。通过求取各数据点至重构模型表面的垂直距离而获取了复杂箱体重构模型的精度,得出了箱体重构模型表面的误差分布情况,验证了曲面重构的质量,完成了重构模型精度的评价。通过对复杂箱体铸件的数字化测量与逆向设计的研究,重构了复杂箱体的三维数字化模型并完成了该模型的精度评价,这些工作有利于箱体铸模的优化设计,并为箱体铸件的加工制造提供了有益的参考,具有一定实际应用价值。
[Abstract]:With the rapid development of economy and society, in the field of manufacturing industry, the demand of product shape design, manufacturing quality and inspection precision is more and more high, so digital measurement and reverse design technology has been widely used in the production of products. At the same time, the digital measurement, design and manufacture are more and more closely related. They constitute the closed-loop digital chain of product manufacturing and meet the requirements of the modern manufacturing industry for the high integration of the system. Digital measurement and reverse design technology plays an increasingly important role in ensuring product quality and improving production efficiency. In this paper, some key techniques of digital measurement and reverse design of complex box castings are studied, such as digital measurement method, data processing method, surface reconstruction method and model precision evaluation technology. For the digital measurement, the internal shape and structure characteristics of the complex box are analyzed, and the external surface of the box is measured by using the three-dimensional laser scanning method based on the measurement of the rotating station, and the point cloud data of the outer surface of the box are obtained. In this paper, a digital measurement method of the chamber cavity based on gypsum model is proposed. The measurement of the chamber cavity is completed, and the point cloud data of the chamber surface are obtained. The data fusion method based on feature point matching is used to complete the data fusion between the point cloud of the outer surface of the box and the point cloud of the inner cavity, and the complete point cloud data of the inside and outside surface of the complex box body are obtained. In the aspect of data processing, the causes of measurement noise points are analyzed, and the de-noising and reduction methods of point clouds are studied, and a fast k-neighborhood search method based on spatial cells is proposed for the de-noising of point cloud data of complex boxes. After analyzing the reduction methods of different data types, a hybrid reduction method combining curvature sampling and uniform sampling is proposed to simplify the point cloud data of the complex box. The effectiveness of the proposed algorithm is verified and good results are obtained. In the process of surface reconstruction, the curve fitting modeling and surface fitting modeling are studied, and the fairing methods of curves and surfaces are analyzed. Based on the point cloud data of the inner and outer surfaces of the complex box, the 3D CAD model of the box is reconstructed. The accuracy of complex box reconstruction model is obtained by calculating the vertical distance from each data point to the surface of the reconstructed model. The error distribution on the surface of the reconstruction model is obtained, and the quality of surface reconstruction is verified. The accuracy of the reconstruction model is evaluated. Through the research on the digital measurement and reverse design of the complex box casting, the 3D digitized model of the complex box is reconstructed and the precision evaluation of the model is completed. These works are beneficial to the optimum design of the casting die of the box. It also provides a useful reference for the machining and manufacturing of box castings and has certain practical application value.
【学位授予单位】：河南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP391.7

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