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基于NURBS非回转对称光学曲面金刚石车削轨迹的研究
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摘要
高精度非回转对称(NRS)光学曲面元件的特殊优越性使其在现代光学系统中有着无法替代的重要用途。随着需求量与日俱增,传统的研磨、抛光等机械加工方法已无法满足其对加工质量与数量的要求。因此,开发新的复杂型面光学曲面超精密成形加工方法,实现高效率、更经济的生产以满足其对精密度、数量和种类的要求成为我国光学制造领域迫切需要解决的难题。
     本课题采用快速刀具伺服车削NRS曲面,创新的提出了基于NURBS曲面分解的方法研究刀具轨迹的形成机理。
     1.研究NURBS曲面的数学模型和表达形式,分析其中各参数的数学与几何意义;介绍其它NRS光学曲面的基本方程与形貌,为刀具轨迹的生成算法提供理论基础。
     2.研究快速刀具伺服车削成型的运动数学模型,将机床的直角坐标系形式转化为极坐标函数表达形式,进而将NURBS曲面与机床、刀具的复合运动相联系,建立了NURBS空间与柱面坐标空间的转化模型。在推导刀位坐标向量变换的基础上,模拟仿真了车削加工NRS曲面的螺旋线刀具轨迹计算方法,并进一步研究刀位坐标在柱面坐标系中时域空间的转换关系,对其基本原理与计算公式进行分析与推导。
     3.对NURBS曲面进行分解,即分解为回转对称与非回转对称NURBS曲面两部分。将数值运算与实际加工成型模型相联系,分别建立了基于直线型和回转型快速刀具伺服机构的车削轨迹算法。包括对在分解中方程参数形式的变换,以及两类车削复合运动刀尖姿态不同的函数关系等问题进行探讨。
     4.在MATLAB和Maple的环境下进行NURBS曲面对球面的拟合,并对拟合精度进行谐波分析。
     5.在VERICUT软件环境下,对计算所得NRS曲面所得的回转对称部分加工轨迹进行了数控仿真。对其进行了数控车削实验,以验证NURBS曲面分解与拟合方法的合理性与正确性。
With modern science and technology to develop, more and more areas of cutting-edge optical components for the growing demand and have an accuracy of nano-scale processing of the target.At the same time, to improve the image quality, reduce processing costs, improve manufacturing efficiency, non-rotary symmetric optical surface of the diamond turning method has become the focus of attention in today's world. In order to improve the optical component manufacturing precision and accuracy to meet the needs of people living in the 21st century higher production needs, in recent years, the global manufacturing industry are actively exploring and developing new, precision, small components of the manufacturing process and methods, of which domestic outside researchers began to more and more concerned about the non-rotating surface of the turning symmetry. This is a concept of the traditional shape of the de-sac turning abandoned, will be hard to imagine the past applied to the machining process to meet the actual needs of production, and its shape is close to the concept of a major innovation in the manufacturing sector. However, non-rotation symmetrical surface technology at the same time, the turning is a knowledge-intensive technology, it is of modern mathematics, physics and other basic science and technology with today's digital manufacturing technology mechanical product of the combination. It broke the tradition of turning many of the technical concept of turning the course of the past to solve the existing problems, abandoned its fixed tool the concept of exercise using the tool servo drive has greatly enhanced the quality of turning parts, as well as the expansion of the turning types of processing components and the continuous improvement of application performance so that more and more widely. It can be said that the non-rotation symmetrical surface-precision turning technology is considered today a major breakthrough in the manufacturing sector, on behalf of the 21st century machinery development.
     However, the non-rotary symmetric shape of optical surfaces turning many problems still exist. The traditional ultra-precision 2-axis rotary lathe can only satisfy the symmetry of the surface form, and who want access to parts the surface of a size, shape accuracy and surface roughness of the non-rotation symmetrical form of free-form surfaces, which is very difficult to meet the turning requirements. Therefore, the complexity of surface shape of precision components on the need for rapid tool and machine tool servo motor complex to be completed together. In the CNC,the tool path generation algorithm has become the focus of the study and one of the difficulties.
     This issue from the perspective of applied research to the world of optical surfaces used in processing the fast tool servo based on a non-rotary symmetric optical surface of the NURBS surface object for the study, carried out by decomposition of the surface approach to generate tool trajectory for the target of non-rotation-symmetric optical surface diamond turning technology trajectory. In view of the current way of forming such a turning in the rapid development of the world, ahead of China's machinery manufacturing industry, as well as in theory, could make a significant contribution in the spline curve, surface model and the rational model in the precision turning process of solving the calculation to improve the trajectory the efficiency of planning to expand the type of CNC machining in the processing of research and reality can better promote the national defense, aerospace, medical and industrial fields, such as guidance, the process of research and has great application value. At present, though foreign scholars in this direction has been an in-depth research, and the 20th century, accompanied by the rapid development of optical manufacturing industry, in particular the optical surface has been formed on the calculation and analysis, manufacturing, testing assessment system, but For free-form NURBS forming the turning, there are still many problems calling for urgent solutions to study such a complex analysis of surface needs to be further in-depth, understanding, planning.
     In this paper, the study of non-rotation-symmetric optical surface means there is no axis of symmetry of the optical surface. NURBS surface for today's world in the production of a wide range of application of life of a surface, but because of the complexity of its mathematical expression and the response is different from the conventional meaning of the mathematical equation, which in the mathematical processing, computer programming, processing, production control with to a lot of trouble, many problems have emerged at the same time. To this end, the core issue in the research paper before the NURBS surface of each parameter described in detail, starting from the NURBS curve, and gradually are given a variety of surface expression of the form of equations in order to facilitate the following specific issues in the study and in the computer software in an intuitive mapping of its geometry, that the necessary papers. In addition, other forms of non-rotation symmetrical surface, such as: off-axis surface, Zernike surfaces, such as ring surface model of the mathematics and geometry, papers have also been briefed for the surface to decompose and the trajectory planning to provide a mathematical basis.
     Non-rotating Symmetric diamond turning of optical surfaces is a fast tool servo machine together with the formation of complex achieved through the establishment of spindle rotation and the displacement function of the tool to achieve a specific processing model. This paper introduces a fast tool servo design concept of the basic structure, as shown in Figure 1. As chart, similar to the slow machine tool servo platform rail, conventional rotary surface of the turning trajectory symmetry; fast tool servo surface to achieve non-slewing the turning symmetry. Paper analyzes the rapid movement of the servo tool, made from such a molding process and the shape of turning conventional features, that is, the tool itself can feed two servo movement. Pointed out that the processing of movement should be reflected in the work itself for the spiral form of the traditional surface for turning the form of concentric circles that are different. At the same time in the rotating spindle, the tool back and forth movement at all times, including a straight line back and forth and back and forth two types of rotary and high frequency is a relative axis movement.
     Based on the NURBS surface is characterized by the vector space, the need to establish processes and tool spindle displacement angle between the function of these two requirements, thesis about the use of cylindrical coordinate system to create a vector space associated with the processing space of thinking, and space coordinates of the basic principles of the conversion process and algorithm are analyzed and deduced. The establishment of a NURBS surface space and machine space cylindrical coordinates of the correspondence between points. On the basis of further processing of the relevant parameters required for an analysis function is derived, the parameters of the transformation locus knife mechanism, the vector method of solving problems in depth. For the next rotation will be curved into symmetric and asymmetric non-rotating two parts to provide the ideological basis and the specific parameters, so that we can track in-depth study of the generation algorithm turning.
     In the CNC machining processes and numerical analysis on the basis of the paper presents the design decomposition of NURBS surface program will be divided into surface: symmetric NURBS surface part of Rotary and non-rotating part of symmetric NURBS surface and the mathematical model through the establishment of two parts inter-relationship. Respectively by solving the extremal surface rotationally symmetric surface structure of the geometric equation of Fourier-based methods and surface integral equation can be divided into two parts to complete the mathematical methods suitable for different processing systems, respectively, the surface decomposition of the work surface.
     Decomposition in the surface on the basis of further research papers NURBS curve curvature of the plane problem, the formula gives the curves of curvature. Further to a point on the curve radius of the value of linking with the coordinates. Tool path planning for the establishment of equations of motion, position coordinates corresponding to the groundwork done. Derived, respectively, based on the linear fast tool servo and rotary-based fast tool servo trajectory of the two types of turning the process of algorithm. Based on the linear fast tool servo applications the solution of differential, the slope of the ways to build on the geometric relationship between the equation, content and meaning easier to understand, but the drawback is that the complex equation, to be used in rotation, respectively, symmetric and non-rotary symmetric equation. Based on the rotary fast tool servo for solving the main manifestation of the specific points of the polar coordinate value, before the papers based on the curvature and the coordinates given by the relationship between the specific points set up one-step equations of motion, the continuous iterative process.
     Paper based on the decomposition of surface applied mathematics MATLAB and Maple software platform, a NURBS surface fitting studies, aimed at reducing the surface morphology of the amplitude asymmetry, and strive to achieve the smallest amplitude asymmetry requirements. Least square method, the Newton interpolation surfaces, NURBS surfaces by scanning process to establish fitting curve, the NURBS surface expression analysis of a large number of data points, control points, given the accuracy of fitting, to be used on surfaces together. For more effective and intuitive assessment of the merits of precision, paper used the principle of harmonic analysis. By fitting the discrete points used to construct the harmonic Fourier integral, after more than right, by solving the amplitude, phase and cycle to analyze the accuracy of the volume difference, and is given from the surface fitting to the harmonic wave analysis of the flow diagram, as shown in Figure 2.
     Since this issue is still in the early exploratory stage, the majority of laboratory equipment is also not perfect, but the lack of the experiment is not perfect, so papers in the surface decomposition, tool path computing, data fitting and the basis of harmonic analysis, only
     After fitting a rotation symmetrical curved surface analysis, simulation and experimental work, that the future of non-rotary symmetric Turning to provide a reference. Analysis through the study opposite, the processing of data points to establish the feasibility of trajectory, the application of VERICUT software platform, a rotary-symmetric NURBS surface machining simulation study to verify the equation before the derivation of the principle of turning the course of the track as well as surface fitting surface morphology of the processability. NC subsequent experiment, as shown in Figure 3, the true realization of the NC machine tool in the tool trajectory curve. And in the turning process by setting the parameters of CNC machine tools turning strongly increased the surface quality of parts. Improve the initial preparatory work for this project. At present, non-rotary symmetric NURBS-based surface diamond turning optical track technology, there are still many problems, as well as its less than full-depth study. The subject of a series of studies of this process not only for expanded research in the field of ideas and also provided the basis for in-depth study is in line with the needs of practical application. In this paper, the direction of the research for the practical application of the initial phase, due to surface decomposition method and tool path generation algorithm and uniqueness of the optimal can not verify, so in future research studies are extremely broad space, and gradually complement, strengthen, simplify and improve in order to improve our country in the field of optical manufacturing technology.
引文
[1] Heinrich, M.D., Wildsmith, C. Need for Precision Engineering in Astigmatic Contact Lenses. Proc. of the ASPE Winter Tropical Meeting on Freeform Optics, Chapel Hill, NC,Feb. 2004, pp. 18-22.
    [2] Bradley, N. D. Computer Numeric Control Generation of Toric Surfaces Proc. of the SPIE, et al., 1994,Vol. 2127, pp. 136-148.
    [3] Jones, R. A. Fabrication of Small Nonsymmetrical Aspheric Surfaces. Applied Optics,1979, Vol. 18, Issue 8, pp. 1244-1246.
    [4]袁哲俊,王先逵.精密和超精密加工技术[M].北京:机械工业出版社,1999.
    [5]王太勇,张志强,王涛,许爱芬,胡世广,赵丽.复杂参数曲面高精度刀具轨迹规划算法[J].机械工程学报,2007,43(12):109-113.
    [6]姚哲,冯景春,王宇晗.面向五轴加工的双NURBS曲线插补算法[J].上海交通大学学报,2008,42(2):235-238.
    [7] Wanna, N. G. Design of Reflective Optical Systems. Master's Degree Thesis, North Carolina State University, Raleigh, Adviser: Thomas A. Dow. 2006.
    [8] Kenneth Garrard,Thomas Bruegge,Jeff Hoffman,Thomas Dow,Alex Sohn. Design tools for freeform optics. Proc.of the SPIE,Vol.5874,pp.95-105.
    [9] Buescher, N. P. Live-Axis Turning. Master's Degree Thesis, North Carolina State University, Raleigh, Adviser: Thomas A. Dow. 2005.
    [10] Winsor, R.S. Optical Design of an Infrared Multi-Object Spectrometer Utilizing a Free-Form Optical Surface. Proc. of the ASPE Winter Tropical Meeting on Freeform Optics, Chapel Hill, NC, 2004, Feb. pp. 79-83.
    [11] Kobayashi, M. Second-Harmonic-Generation Microscope with A Microlens Array Scanner. Optics Letters, et al., 2002,Vol. 27, Issue 15, pp. 1324-1326.
    [12] Wang, X. K., Wu, D., Yuan, Z.J. Experimental Research on the Linear Motor Micro-Feed Device with High Frequency Response, Long Travel and High Accuracy. Annals of the CIRP, 1991,Vol. 40, No. 1, pp. 379-382.
    [13] Ruckman, J. L., Fess, E. M., Pollicove, H. M. Deterministic Processes for Manufacturing Conformal (Freeform) Optical Surfaces. Proc. of the SPIE, Vol. 4375, 2001, pp. 108-113.
    [14] F.Z.Fang,H.Wu,Y.C.Liu. Modelling and experimental investigation on nanometric cutting of monocrystalline silicon. INTERNATIONAL JOURNAL OF MACHINE TOOLS & MANUFACTURE[J], 2005,45:1681-1686.
    [15]王洪祥,孙涛,董申,李旦.超精密车削表面微观形貌的几何建模与仿真研究[J].中国机械工程,2002,13(13):1131-1134.
    [16]李刚,刘华明,王新龙. CAD/CAM中曲面求交技术的研究[J].高技术通讯,2000,6:57-58.
    [17]徐立国,赵继,徐卫. NURBS曲面无退刀双螺旋线轨迹规划法.中国机械工程[J]. 2006,17(18):1924-1927.
    [18] Ludwick, S. J. A Rotary Fast Tool Servo for Diamond Turning of Asymmetric Optics. Ph.D. Dissertation, Massachusetts Institute of Technology, June 1999, Adviser:David L. Trumper.
    [19] Yi, Y. and Li, L. Design and fabrication of a Microlens Array by Use of a Slow Tool Servo. Optics Letters, 2005,Vol. 30, Issue 13, pp. 1707-1709.
    [20] Montesanti, R. High Bandwidth Rotary Fast Tool Servos and A Hybrid Rotary /Linear Electro-Magnetic Actuator. PhD dissertation, Massachusetts Institute of Technology, Adviser: David L. Trumper.2005.
    [21]吉贝?德芒热,让皮尔?晡热.曲线与曲面的数学[M].北京:商务印书馆,2000.
    [22] Lu, X. Electromagnetically-Driven Ultra-Fast Tool Servos for Diamond Turning. Ph.D. Dissertation, Massachusetts Institute of Technology, Sept. 2005, Adviser: David L.Trumper.
    [23] Bingham, R. G. A Novel Automated Process for Aspheric Surfaces. Proc. Of the SPIE, 2000,Vol. 4093, Oct. pp. 445-450.
    [24] W.Ma,J.-P.Kruth. NURBS Curve and Surface Fitting for Reverse Engineering. Advanced Manufacturing Technology[J]. 1998,14:918-927.
    [25]吴大任.微分几何讲义[M].北京:人民教育出版社,1982.
    [26]鞠大鹏,张金萍.三次均匀有理B样条曲线轮廓数控加工刀位轨迹计算[J].辽宁师专学报, 2005, 7(1):86-88.
    [27]董云风.基于NURBS曲面的逼近及数控加工技术的研究.华北电力大学硕士学位论文[D]. 2006.
    [28]姜兴序.金属切削机床与刀具[M].湖北:华中理工大学出版社,1989.
    [29]徐国良.自由曲面数控加工刀具轨迹的规划与计算[J].中国科技信息,2005,13:122-124.
    [30]辛企明,孙雨南,谢敬辉.近代光学制造技术[M].北京:国防工业出版社,1997.
    [31] Chao-Chang A.Chen,Chien-Ming Chen,Jr-Rung Chen. Toolpath generation for diamond shaping of aspheric lens array. Journal of Materials Processing Technology[J], 2002,19:637-641.
    [32] RALF MAYER. How to Make Polymer Optics for High Volume and High Precision Applications. PLASTIC OPTICS[J], 2007,4(12):46-51.
    [33]吴丹,孙京海,王先逵.非轴对称车削成型方法探讨.清华大学学报(自然科学版)[J],2006,46(11):1832-1835.
    [34]张元良,刘欣,方加宝,陈懋圻.非轴对称光学表面超精密加工若干关键技术[J].大连理工大学学报. 1999,39(6):766-770.
    [35] Lei Piegl,Wayne Tiller. The NURBS Book[M]. Mercedesdruck,Berlin,1996.
    [36] ZWXu,F Z Fang,Y Q Fu,S J Zhang,T Han and J M Li. Fabrication of micro/nano-structures using focused ion beam implantation and XeF2 gas-assistedetching. JOURNAL OF MICROMECHANICS AND MICROENGINEERING[J], 2009,19:1-9.
    [37] Ying Liang Ma,W.T.Hewitt. Point inversion and projection for NURBS curve and surface:Control polygon approach. Computer Aided Geometric Design[J], 2003,20:79-99.
    [38] Tomhe, Y. Machining of Freeform Optical Surfaces By Slow Slide. Proceedings of the ASPE 18th Annual Meeting.2003.
    [39] Patterson, S.R., and Magrab, E.B. The Design and Testing of A Fast Tool Servo for Diamond Turning. Precision Engineering, 1985,Vol. 7, No. 3, pp. 123.
    [40] Woronko A., and Altintas, Y. A Piezo Tool Actuator for Precision Turning of Hardened Shafts. Annals of the CIRP, 2002,Vol. 51, No. 1, pp. 303-306.
    [41] Roblee, J. W. Live-Axis Turning for the Fabrication of Non-Rotationally Symmetric Optics. NASA STTR 2003 Solicitation, Proposal Number: 03-II T4.01-9768.
    [42] Plummer, W. T. Free-form Optical Components in Some Early Commercial Products. Proc. of the ASPE Winter Tropical Meeting on Freeform Optics, Chapel Hill, NC,Feb. 2004, pp. 68-71.
    [43]刘广超,周学才.空间椭圆弧轨迹规划的实现方法.机器人技术与应用[J]. 2002,3:32-35.
    [44]韩成顺.大型光学非球面超精密加工新方法及其几何模型的研究.哈尔滨工业大学博士学位论文[D]. 2005.
    [45] Weck, M. H. A New Hybrid Concept for A Long Stroke Fast Tool Servo System. Proc. of the 10th Annual Meeting of the ASPE. 1995.
    [46] Falter, K. J. and Youden, D. H. The Characterization and Testing of A Long Stroke Fast Tool Servo. Proc. of the 8th International Precision Engineering Seminar, 1995, pp. 225-228.
    [47] F Z Fang,X D Zhang,and X T Hu.Cylindrical coordinate machining of optical freeform surfaces. OPTICS EXPRESS[J], 2008,12(5):7323-7329.
    [48] X D Zhang,F Z Fang,H B Wang,G S Wang,G S Wei and X T Hu.Ultra-precision machining of sinusoidal surfaces using the cylindrical coordinate method. JOURNAL OF MICROMECHANICS AND MICROENGINEERING[J], 2009,19:1-7.
    [49] F.Z.Fang, V.C. Venkatesh. Diamond Cutting of Silicon with Nanometric Finish. Annalsof the ClRP[J], 2008,47(1):45-49.
    [50]阿尔达玛茨基.光学零件的金刚石加工[M].北京:机械工业出版社,1987.
    [51]庞滔,郭大春,庞楠.超精密加工技术[M].北京:国防工业出版社,2000.
    [52]田守信,马仁勇,郭宝金.高精度及特种光学零件制造与检测[M].湖北:华中理工大学出版社,1991.
    [53]俞武嘉,傅建中,陈子辰.五轴加工刀具路径生成的有效加工域规划方法[J].机械工程学报,2007,43(7):179-183.
    [54] Falter, P. and Dow, T. A. Diamond-Turning Apparatus for Fabrication of Non-rotationally Symmetric Surface Generation. Proc. of the International Congress for Ultra-precision Technology, Aachen, 1988, pp. 187-201.
    [55] I.Durazo-Cardenas,P.Shore, X.Luo,T.Jacklin,S.A.Impey,A.Cox. 3D characterisation of tool wear whilst diamond turning silicon. ScienceDirect[J]. 2007,262:340-349.
    [56] Wei Tai and Rudolf Schwarte. Design of an aspherical lens to generate a homogenous irradiance for three-dimensional sensors with a light-emitting-diode source. APPLIED OPTICS[J]. 2000,39(12):5801-5805.
    [57] Allen Y.Yi,Chunning Huang,Fritz Klocke,Christian Brecher,Guido Pongs,Markus Winterschladen,Axel Demmer,Sven Lange,Thomas Bergs,Michael Merz,and Frank Niehaus. Development of a compression molding process for three-dimensional tailored free-form glass optics. APPLIED OPTICS[J]. 2006,1(9):6511-6518.
    [58] Yin Zhongwei,Jiang Shouwei. Iso-phote based adaptive surface fitting to digitized points and its applications in region-based tool path generation,slicing and surface triangulation. COMPUTERS IN INDUSTRY[J]. 2004,55:15-28.
    [59] Christian Brecher,Markus Winterschladen,Sven Lange,Michael Merz Fraunhofer. Rapid manufacture of high precision optical freeform surfaces. Optics Manufacture[J]. 2006,80-81.
    [60] Rakuff, S. Development of a Precision Long-Range Fast Tool Servo System for Diamond Turning. Ph.D. Dissertation, University of North Carolina at Charlotte, Adviser:James F. Cuttino. 2004.
    [61] X.Zhiming,C.Jincheng and F.Zhengjin. Performance Evalauation of a Real-Time Interpolation Algorithm for NURBS Curves. Advanced Manufacturing Technology[J]. 2002,20:270-276.
    [62] F.Z.Fang,H.Wub,W.Zhouc,X.T.Hu. A study on mechanism of nano-cutting single crystal silicon. Journal of Materials Processing Technology[J], 2007,184:407-410.
    [63] F.Z.Fang,V.C.Venkatesh2 and G.X.Zhang. Diamond Turning of Soft Semiconductors to Obtain Nanometric Mirror Surfaces. The International Journal of AdavancedManufacturing Technology[J], 2002,19:637-641.
    [64] F.Z.Fang,V.C.Venkatesh2 and G.X.Zhang. Diamond Turning of Soft Semiconductors to Obtain Nanometric Mirror Surfaces. The International Journal of Adavanced Manufacturing Technology[J], 2002,19:637-641.
    [65] F Z Fang,H Wu,X D Liu,Y C Liu and STNg. Tool geometry study in micromachining. JOURNAL OF MICROMECHANICS AND MICROENGINEERING[J], 2003,13:726-731.
    [66]韩成顺,张龙江,董申,唐余勇.大型光学非球面零件超精密切削新方法[J].哈尔滨工业大学学报,2007,39(7):1062-1065.
    [67]陈怀琛,吴大正,高西全. MATLAB及在电子信息课程中的应用[M].北京:电子工业出版社,2005.
    [68]陈蔚芳,王宏涛.机床数控技术及应用[M].北京:科学出版社,2005.
    [69]苏金明,王永利. MATLAB7.0实用指南[M].北京:电子工业出版社,2004.
    [70]蒲俊,吉家锋. Matlab工程数学解题指导[M].上海:浦东电子出版社,2001.
    [71]毛红兵,马继红.基于MATLAB的系统分析与设计—信号处理[M].西安:西安电子科技大学出版社,1998.
    [72]陈怀琛.数字信号处理—MATLAB释义与实现[M].北京:电子工业出版社,2004.
    [73]近藤次郎,高桥磐郎,小柳芳雄.微分方程傅立叶分析[M].沈阳:辽宁人民出版社,1981.
    [74]阿塔贝可夫.谐波分析和运算子方法[M].北京:国防工业出版社,1964.
    [75] Walter Gander.用Maple和MATLAB解决科学计算问题(第三版)[M].北京:高等教育出版社,1999.
    [76]马春庭,高萍,吴开腾,徐立新.掌握和精通Maple[M].北京:高等教育出版社,2000.
    [77]毛英泰.误差理论与精度分析[M].北京:国防工业出版社,1982.
    [78]丁振良.误差理论与数据处理[M].哈尔滨:哈尔滨工业大学出版社,2002.
    [79]施法中.计算机辅助几何设计与非均匀有理B样条[M].北京:高等教育出版社,2002.

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