共查询到20条相似文献,搜索用时 156 毫秒
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文章基于CATIA自由曲面反求技术,对车身曲面设计进行了研究。通过对宝马三视图的数据采集和处理、曲面的构建以及曲面分析,进行车身曲面的数字化建模,反求出汽车曲面的三维数字模型。解决了通过三视图实现快速逆向工程实体三维数字建模问题。 相似文献
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重点介绍三坐标测量自由曲面的反求技术。通过对自由曲面数字化过程中数据获取、测量数据处理和曲面重构的研究,得到鼠标外壳的三维模型,极大地提高了设计质量和效率。 相似文献
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逆向工程是产品设计与加工的一种新方法,已经成为企业不可或缺的设计手段.以汽车后大梁力研究对象,介绍了反求设计关键技术以及使用Imageware进行自由曲面反求设计的一般方法.通过点云数据的采集、数据预处理、特征线构建以及三维模型重建和曲面质量分析和编辑等设计过程,介绍了利用Imageware实现汽车后大梁这种复杂曲面的反求设计的整个步骤,详细介绍了利用Imageware进行特征线重构和曲面重构的关键技术,以及通过对特征线和曲面的再次编辑,实现了汽车后大梁的反求设计并满足了企业的设计精度要求.并介绍了反求设计的一般设计流程以及在Imageware中进行反求设计的技巧. 相似文献
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反求工程技术在机械产品设计中的应用 总被引:6,自引:1,他引:6
对机械产品的反求过程进行了系统分析,对反求三维测量、利用反求软件进行曲面重构、及三维造型等反求工程中的关键技术阶段进行了详细的探讨。 相似文献
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基于少量测量数据的复杂曲面重构 总被引:1,自引:0,他引:1
研究了少量测量数据情况下的复杂曲面反求技术,给出亍曲面重构的具体实案.以叶轮为例,介绍了复杂曲面重构中的数据采集、三维造型和误差检测、修正的方法,解决了反求工程中少量点曲面重构的技术难点. 相似文献
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This paper presents an any-degrees-of-freedom (anyDOF) registration method for the characterization of freeform surfaces. The method attempts to fill the research gap regarding traditional surface registration methods which are normally dedicated to solving the global optimization problem with all DOF but they lack flexibility. The proposed anyDOF method is capable of registering surfaces with any specified combination of DOF. This is particularly useful when some of the DOF are known to be unchanged according to the a priori knowledge. The anyDOF surface registration method is regarded as a typical optimization problem of finding the minimum distance from target surface to the reference surface, with constraints of the unwanted DOF. The problem is solved by the Levenberg-Marquardt method. Simulated experiments for a two-dimensional (2D) profile and a three-dimensional (3D) surface were undertaken, together with three measurement experiments including a fluid-jet polished surface, a bonnet polished surface and a diamond machined freeform surface. Experimental results show that the anyDOF registration method is highly flexible in the characterization of freeform surfaces. 相似文献
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数据同化方法是气象、海洋进行数值预报的主要方法,四维数据同化的提出提高了其预报的准确性。四维数据同化的实质就是由大量观测值去确定出这些观测值所决定的曲面,而曲面重构也是依据测量所获得的大规模数据点重构实物的曲面模型。因此,本文提出了将数据同化方法应用于曲面重构的设想,文中分别介绍了如何用迭代寻优法进行网格优化和变分伴随同化法进行曲面重构。试验结果表明:优化后的三角网格更趋于正三角形,同化后的曲面逼近精度明显提高,达到了提高重构曲面与实物一致性的目的。 相似文献
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Chenggang Li Sanjeev Bedi Stephen Mann 《The International Journal of Advanced Manufacturing Technology》2006,29(11-12):1115-1124
In this paper, machining a ruled surface with a conical tool is discussed. The main goal of our method (the spatial tangent points shift method) is to minimize the error between the given surface and the machined surface. A three-step-optimization is applied. In each step, the cutting tool is tangential to two guiding rails. The guiding rails can be located anywhere within the ruled surface. The first step is to initialize the tool position and find the point with the biggest deviation; the second step tries to minimize the surface error by moving the guiding rails towards the point with the largest deviation along the ruling line, which reduces the surface error to nearly half of its original value; the third step is to shift the tool position along the feed direction to further reduce the error between the given surface and the machined surface. We test the effect of various tool parameters on our method, and we compare our method to other methods of milling with a conical tool. Finally, we used our method to machine a test part and the accuracy of the assessment was verified experimentally. 相似文献
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逆向工程软件的曲面反求中,曲率较大的地方往往难以得到较好的曲面反求效果,针对该问题提出了一种基于曲率变化的分块曲面构建拼接方法。该方法根据曲率显示的点的颜色特征进行点云数据的分割,分别获得单片光滑曲面,然后将单片曲面拼接起来以实现完整的自由曲面造型。在曲面拼接过程中,调整两片曲面相邻两列控制点,使其三点共线,以达到拼接处一阶连续。最后通过一个典型的实例证明该方法构造的曲面与原始点云的最大误差为由点阵直接拟合生成的曲面误差的1/3,为由点一线一面构造的整块曲面误差的1/5。 相似文献
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一种基于能量法的自由曲面展开算法 总被引:4,自引:0,他引:4
提出了一种基于能量法的自由曲面展开算法,适用于任意复杂自由曲面的展开.根据建立的曲面能量模型,采用映射法进行曲面的Delaunay三角网格划分,并计算空间网格三角形点的变形能,然后进行变形能的释放,得到自由曲面展开后的二维平面.能量法不拘于问题的形式,可以用来求解一般的问题,该算法具有一定的通用性,适用于CAD/CAM中的曲面展开问题. 相似文献
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Donggo Jang Kwangsoo Kim Jaehun Jeong 《The International Journal of Advanced Manufacturing Technology》1999,15(3):210-216
A method is proposed for Gregory surface approximation to 3D array data points. Surface approximation is the process of constructing
a compact representation to model an object surface based on a fairly large number of measured 3D data points. Based on an
adaptive subdivision technique, the proposed method begins with a rough initialisation of the surface and progressively refines
it in successive steps in the regions where the data is poorly approximated. The method has been implemented using piecewise
bicubic Gregory patches with G 1 continuity. An advantage of this approach is that the refinement is essentially local, reducing
the computational requirements that permit the processing of a large number of data points This method, combined with the
inverse offsetting method, can be used to obtain an offset surface without self-interference. The offset surface can be used
to generate gouging-free CL tool paths for machining compound surfaces on milling machines. 相似文献