共查询到17条相似文献,搜索用时 185 毫秒
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一种四次有理插值样条及其逼近性质 总被引:3,自引:0,他引:3
1引言有理样条函数是多项式样条函数的一种自然推广,但由于有理样条空间的复杂性,所以有关它的研究成果不象多项式样条那样完美,许多问题还值得进一步的研究.近几十年来,有理插值样条,特别是有理三次有理插值样条,由于它们在曲线曲面设计中的应用,已有许多学者进行了深入研究,取得了一系列的成果(见[1]-[7]).但四次有理插值样条由于其构造所花费的计算量太大以及在使用上很不方便而让人们忽视了其重要的应用价值,因此很少有人研究他们.实际上,在某些情况下四次有理插值样条有其独特的应用效果,如文[8]建立的一种具有局部插值性质的分母为二次的四次有理样条,即一个剖分 相似文献
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几种有理插值函数的逼近性质 总被引:6,自引:1,他引:5
1 引 言在曲线和曲面设计中,样条插值是有用的和强有力的工具.不少作者已经研究了很多种类型的样条插值[1,2,3,4].近些年来,有理插值样条,特别是三次有理插值样条,以及它们在外型控制中的应用,已有了不少工作[5,6,7].有理插值样条的表达式中有某些参数,正是由于这些参数,有理插值样条在外型控制中充分显示了它的灵活性;但也正是由于这些参数,使它的逼近性质的研究增加了困难.因此,关于有理插值样条的逼近性质的研究很少见诸文献.本文在第二节首先叙述几种典型的有理插值样条,其中包括分母为一次、二次的三次有理插值样条和仅基于函数值… 相似文献
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1 引言和辅助引理 关于样条插值的渐近展开,目前已有许多工作,这些工作主要限于周期样条插值和基样条(cardinal spline)插值情形,它们不仅给出了插值误差的渐近展开,而且获得了逐项渐近展开。对于实际中应用最多的有限区间上的样条插值的渐近展开问题,由于受端点条件的影响,呈现十分复杂的局面。目前的工作只是获得了渐近展开结果,并未获得逐项渐近展开,且主要针对二、三次这类低次样条插值情形,考虑高次样条有良好的逼近性质,特别是其中四、五次样条插值在实际应用中被广泛采用,本文致力于研究四次样条插值问题,获得了其误差 相似文献
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基于样条插值的模糊控制算法 总被引:1,自引:0,他引:1
利用三次样条插值函数,直接由控制输入输出数据对建立了控制输入与控制输出之间的映射关系,得到了一元三次样条插值控制算法和二元双三次样条插值控制算法,并将二者分别用于单输入单输出系统和双输入单输出系统的仿真控制.仿真结果表明,上述方法是可行的,并且基于三次样条函数的模糊插值控制,具有响应快,无超调,稳态误差极小等很好的控制效果.其设计简单,不需要过多规则,对稀疏规则库条件下的控制器设计尤为适用. 相似文献
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Qinghua Sun Fangxun Bao Jianxun Pan Qi Duan 《Mathematical Methods in the Applied Sciences》2013,36(10):1301-1309
A weighted blending interpolator, a kind of smooth rational spline based only on function values, is constructed using a rational cubic spline and a polynomial spline. In order to meet the needs of practical design, a new control method is employed to control the shape of curves. The advantage of the method is that it can be applied to modify the local shape of an interpolating curve by selecting suitable parameters and weight coefficients simply. Also, when the weight coefficient is in [0,1], the error estimation formula of this interpolator is obtained. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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In order to relieve the deficiency of the usual cubic Hermite spline curves, the quartic Hermite spline curves with shape parameters is further studied in this work. The interpolation error and estimator of the quartic Hermite spline curves are given. And the characteristics of the quartic Hermite spline curves are discussed. The quartic Hermite spline curves not only have the same interpolation and conti-nuity properties of the usual cubic Hermite spline curves, but also can achieve local or global shape adjustment and C2 continuity by the shape parameters when the interpolation conditions are fixed. 相似文献
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Qi Duan Botang Li K. Djidjeli W. G. Price E. H. Twizell 《Journal of Applied Mathematics and Computing》1999,6(3):537-547
Controlling the convexity and the strain energy of the interpolating curve can be carried out by controlling the second-order derivative of the interpolating function. In [1], the rational cubic spline with linear denominator has been used to constrain the convexity and the strain energy of the interpolating curves, but it does not work in some case. This paper deals with the weighted rational cubic spline with linear denominator for this kind of constraint, the sufficient and necessary condition for controlling the convexity and strain energy of the interpolating curves are derived, and a numerical example is given. 相似文献
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Wei-Xian HuangGuo-Jin Wang 《Applied mathematics and computation》2011,217(9):4644-4653
This paper presents a new weighted bivariate blending rational spline interpolation based on function values. This spline interpolation has the following advantages: firstly, it can modify the shape of the interpolating surface by changing the parameters under the condition that the values of the interpolating nodes are fixed; secondly, the interpolating function is C1-continuous for any positive parameters; thirdly, the interpolating function has a simple and explicit mathematical representation; fourthly, the interpolating function only depends on the values of the function being interpolated, so the computation is simple. In addition, this paper discusses some properties of the interpolating function, such as the bases of the interpolating function, the matrix representation, the bounded property, the error between the interpolating function and the function being interpolated. 相似文献
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In this paper we construct developable surface patches which are bounded by two
rational or NURBS curves, though the resulting patch is not a rational or NURBS surface
in general. This is accomplished by reparameterizing one of the boundary curves. The
reparameterization function is the solution of an algebraic equation. For the relevant case
of cubic or cubic spline curves, this equation is quartic at most, quadratic if the curves are
Bézier or splines and lie on parallel planes, and hence it may be solved either by standard
analytical or numerical methods. 相似文献