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谢超 《西安文理学院学报》2015,(1):76-79
将非圆曲线采用等距的方法进行分割,建立数学模型,对每一段等距分割产生的误差进行计算,推导出实际产生最大误差公式,设定实际产生最大误差值为变量参数,根据变量参数的大小减少或增加等距分割的步距,使数控编程产生的误差满足技术要求的最大误差,应用实例验证该方法的有效性. 相似文献
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第二型广义曲线积分和广义格林公式是文献[1]中第二型曲线积分和格林公式的推广。本文主要研究了第二型广义曲线积分定义、性质和计算方法以及闭围区域上被积函数为有瑕点的二重积分与围成该区域的边界曲线上的曲线积分之间的关系,并给出了相关结论。 相似文献
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利用-元函数的广义积分思想,对有界函数的第二类曲线积分予以推广.给出了被积函数是无界函数的第二类广义曲线积分,并讨论了有关的性质、敛散性的判定及相应的计算方法. 相似文献
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吴炳进 《黎明职业大学学报》2011,(3):22-24
以鼓风机扭叶转子的端面曲线方程为基础,采用截面铣削法,首先求出扭叶转子螺旋曲面方程,再由扭叶转子螺旋曲面的法向等距面推导出球头铣刀中心在x—y平面上的轨迹曲线,并实例验证所求轨迹的可行性。 相似文献
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提出三焦点广义椭圆的概念,给出三焦点广义椭圆的画法及其轨迹方程,建立三焦点广义椭圆的重心M到三焦点广义椭圆轨迹曲线上动点p的距离d的数学模型,研究三焦点广义椭圆构件对力与速度的传动特性及其在工业上的应用。 相似文献
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广义积分中值定理是数学分析中的一个重要定理,对微分中值定理、曲线和曲面积分中值定理等的认识有很大帮助.本文根据广义积分中的广义积分和积分中值定理的定义和相关性质,扩展到广义积分中值定理中,重点在单调区间上的广义积分中值定理、带有参数的广义积分中值定理、广义Riemann积分中的推广这三方面进行探讨. 相似文献
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INTRODUCTION Offset curves/surfaces, also called parallel curves/surfaces, are defined as the locus of the points which are at constant distance along the normal from the generator curves/surfaces. As for a planar gen- erator curve Γ:C(t)=(x(t),y(t)), the parametric speed and its norm σ(t) are defined respectively as (Farouki, 1992) C ′( t ) =( x ′( t ), y ′(t )),σ (t ) = x ′ 2 (t ) y ′2(t ). (1) Subsequently the offset curve of the generator curve, which is at constant distanc… 相似文献
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The problem of parametric speed approximation of a rational curve is raised in this paper. Offset curves are widely used in
various applications. As for the reason that in most cases the offset curves do not preserve the same polynomial or rational
polynomial representations, it arouses difficulty in applications. Thus approximation methods have been introduced to solve
this problem. In this paper, it has been pointed out that the crux of offset curve approximation lies in the approximation
of parametric speed. Based on the Jacobi polynomial approximation theory with endpoints interpolation, an algebraic rational
approximation algorithm of offset curve, which preserves the direction of normal, is presented.
Project supported by the National Basic Research Program (973) of China (No. 2002CB312101) and the National Natural Science
Foundation of China (Nos. 60373033 and 60333010) 相似文献
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INTRODUCTIONTheOSSI(OffsetSurface/SurfaceIntersection)problemisasub-problemofgeneralSSI.AlthoughtheOSSIproblemcanberesolvedbyapplyinggeneralSSIalgorithm,itiscomputationallyexpensiveandexhaustive.Inrecentdecades,effortshavebeenfocusedoncomputingSSIexactly,efficiently,androbustlyinageneralsetting(Abdel-MalekandYeh,1997;Changetal.,1994;BurkeandSabharwal,1996;Mullenheim,1991).Thesetechniquescanbeclassifiedmainlyintofivecategories:algebraic,latticeevaluation,marching(tracing)method,… 相似文献
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Said-Ball曲线的细分算法 总被引：1，自引：0，他引：1
设实数c（0〈c〈1）将广义Said-Ball曲线r（u），0≤u≤1分为两段r[0，c]（u）=r[cu]和r[c，1]（M）=r（c＋（1-c）u），0≤u≤1.利用对偶泛函，给出用显式表示的Said-Ball曲线的细分算法（细分矩阵）。所给出的显示细分矩阵有利于曲线的生成与合并方面的研究。 相似文献
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Conventional methods for solving intersections between two offset parametric surfaces often include iteratively using computationally
expensive SSI (surface/surface intersections) algorithm. In addition, these methods ignore the relations between the intersection
curves of parametric surfaces with different offset distances. The algorithm presented in this paper, makes full use of the
topological relations between different intersection loops and calculates intersection loops with the help of previously calculated
intersection loops. It first pre-processes two parametric surfaces to obtain the characteristic points, called topology transition
points (TTPs), which can help in the subsequent finding of the topologies of the intersection curves. Then these points are
categorized into several distinct groups, and we can determine the calculation strategy for searching initial points by analyzing
the properties of these TTPs on the surfaces. Hence, all intersection curves can be marched from initial points by the tracing
algorithm. The proposed algorithm could calculate intersection curves robustly and effectively, and has been tested to be
capable of overcoming the degenerate conditions such as loop and singularities leaking that occur frequently in conventional
algorithms.
Project supported by the National Research Foundation for the Doctoral Program (No. 2000033554) of Higher Education of China
and the Natural Science Foundation of Zhejiang Province, China (No. 6001107) 相似文献
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构造了与给定多边形相切的分段三次、五次和六次可调广义Ball曲线,所构造的曲线分别是C1,C2和C3连续,而且对切线多边形是保形的.曲线的所有控制点由切线多边形的顶点直接计算产生.给出了在保持公共连接点处相应连续的条件下内控制点的活动范围.曲线可以在一定范围内做局部修改.计算实例表明文中方法是灵活、方便、有效的. 相似文献
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LI Jun HAO Peng-wei 《浙江大学学报(A卷英文版)》2006,7(7):1168-1177
INTRODUCTION Homogeneous matrices are matrices used to represent geometric transformations for homogene- ous coordinates. Because they provide uniform rep- resentation for various transformations, they are widely used in the computer graphics community. As a homogeneous matrix corresponds to a geometric transformation, a curve on the set of homogeneous matrices can be taken as a piece of motion. Thus interpolation between those matrices is of high in- terest in many applications such as c… 相似文献
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In order to fair and optimize rational cubic B-spline curves used frequently in engineering, and to improve design system function, some formulae on the degree and the knot vector, of the product of three B-spline functions, are presented; then Marsden’s identity is generalized, and by using discrete B-sline theory, the product of three B-spline functions is converted into a linear combination of B-splines. Consequently, a monotone curvature variation (MCV) discriminant for uniform planar rational cubic B-spline curves can be converted into a higher degree B-spline function. Applying the property of positive unit resolution of B-spline, an MCV sufficient condition for the curve segments is obtained. Theoretical reasoning and instance operation showed that the result is simple and applicable in curve design, especially in curve fair processing. 相似文献
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基于Origin的光学实验计算机仿真 总被引：1，自引：0，他引：1
以多缝衍射实验为例,介绍利用Origin实现光学实验计算机仿真的方法。此新方法实现过程简易,可以得到细致逼真的仿真图样和任意方向的光强分布曲线,适合推广到多个光学实验的计算机仿真中,为光学的理论分析与实验教学提供方便。 相似文献