Forward displacement analysis of a redundant parallel manipulator by approximation algorithms     

ZHAO Yong-jie  QIU Ke 《重庆大学学报(英文版)》2010,9(1):12-20

This paper presents the forward displacement analysis of an 8-PSS （prismatic-spherical-spherical） redundant parallel manipulator whose moving platform is linked to the base platform by eight kinemtic chains consisting of a PSS joint and a strut with fixed length. A general approximation algorithm is used to solve the problem. To avoid the extraction of root in the approximation process, the forward displacement analysis of the 8-PSS redundant parallel manipulator is transformed into another equivalent problem on the assumption that the strut is extensible while the slider is fixed. The problem is solved by a modified approximation algorithm which predicates that the manipulator will move along a pose vector to reduce the difference between the desired configuration and an instantaneous one, and the best movement should be with minimum norm and least quadratic sum. The characteristic of this modified algorithm is that its convergence domain is larger than that of the general approximation algorithm. Simulation results show that the modelified algorithm is general and can be used for the forward displacement analysis of the redundant parallel manipulator actuated by a revolute joint.  相似文献   

粗糙模糊集的截集性质及其应用     

于海  黄盛 《洛阳师范学院学报》2010,29(5):21-23

本文研究了粗糙模糊集的截集性质,粗糙模糊集的上、下近似算子具有保截集性质.在此基础上给出了粗糙模糊集的分解定理,证明了模糊上、下近似算子是其限制在经典集合上算子的典范扩张.最后,利用截集性质简化了模糊集的粗糙度和精度的计算,并给出一个应用实例.  相似文献   

矩阵方程AXB＋CYD=E的中心对称解的递推算法     

王伟  刘莉 《宁夏师范学院学报》2010,31(3):5-9,35

讨论了矩阵方程AXB＋CYD=E中心对称解的迭代算法,该算法能够判断矩阵方程是否有中心对称解,在有解的条件下,能得到它的中心对称解,而且在选取特殊的初始矩阵时,该算法能够求出矩阵方程的极小范数中心对称解,以及对给定的矩阵进行最佳逼近的中心对称解．  相似文献   

Comparison of numerical and analytical solutions for fly casting dynamics     

Caroline?Gatti-Bono  N.?C.?PerkinsEmail author 《Sports Engineering》2003,6(3):165-175

This paper presents an approximate analytical model of the dynamics of a tapered fly line during a standard overhead cast. During casting, the line forms a nonlinear propagating wave that is frequently referred to as a ‘loop’ by fly casters. The geometry of the loop is described by three distinct parts: a straight bottom segment (attached to a stationary fly rod), a semi-circular segment that is propagating (i.e. the loop), and a straight top segment that is also propagating, (i.e. the traveling line). A fly (particle) is attached at the end of the traveling line. A work-energy balance yields the velocity of the fly as a function of the length of the traveling line. For a uniform fly line (level line), a closed-form solution is found, while for a tapered fly line, the solution is obtained by quadrature. A critical loop diameter arises in the analysis, and it determines whether the final velocity of the fly is greater or lesser than the initial velocity of the traveling line. The analytical solutions are critically compared against numerical solutions of a general model for fly line dynamics that relaxes many of the assumptions employed in the analytical model. The agreement between the two solutions remains close during the loop propagation phase, provided a significant amount of fly line remains in the traveling line. However, as the traveling line vanishes and the loop ‘turns over’, the two solutions diverge abruptly due to the many simplifying assumptions employed in the analytical model.  相似文献   

修正的q-Stancu—Beta算子的加权统计逼近性质     

蔡清波 《泉州师范学院学报》2014,(2):55-59

基于q-整数的定义,引入了一类修正的q-Stancu—Beta算子,由算子的各阶矩量、中心矩量及加权光滑模结合统计逼近的概念,得到了算子的加权统计收敛定理,并研究了算子的局部逼近性质,得到了算子的局部逼近定理．  相似文献   

严格凸Banach空间中最佳逼近元的存在与唯一性     

金茂明  孙胜利 《商丘师范学院学报》2000,16(4):51-52

在严格凸Ｂａｎａｃｈ空间中,引入保持严格凸性的范数,得到了严格凸Ｂａｎａｃｈ空间积空间的严格凸性,证明了单空间和积空间中关于无穷维紧凸子集最佳逼近元的存在与唯一性定理,改进和推广了某些已有结果。  相似文献   

L~ψ空间中的Jackson定理   总被引：2，自引：0，他引：2  

伍火熊 《湘南学院学报》2000,(4)

研究了Lψ空间中的函数用多项式逼近的问题 ,证明了Jackson定理 .  相似文献   

关于Cauchy中值定理中值的渐近性与收敛速度     

唐荣荣 《湖州师范学院学报》2000,22(6):7-12

对Ｃａｕｃｈｙ中值定理的中值的渐近性给出了一些结果,并建立了收敛速度。  相似文献   

q-Durrmeyer-Stancu算子的统计逼近性质     

任美英 《南平师专学报》2014,(5)

本文引进一类q-Durrmeyer-Stancu算子,并研究该算子列的一些统计逼近性质。得到算子列的统计逼近定理,同时借助连续模和Lipschitz函数类给出算子列统计收敛速度的估计。  相似文献   

美式有分红看涨篮子期权解析近似定价模型     

唐耀宗 《内江师范学院学报》2014,(10):19-22

针对有分红美式篮子看涨期权,使用格点法与蒙特卡罗模拟法定价时,会产生＂维数灾难＂.对此,将期权的收益项进行适当改写,然后利用几何平均与算术平均之间的关系,将标的资产组合从算术平均转化为几何平均;然后在单标的资产美式期权解析近似定价模型的基础上,提出了一种解析近似方法为美式分红篮子看涨期权进行定价（Analytical Approximation Method,简称AAM）.此方法解决了＂维数灾难＂问题.最后,通过数值结果验证了该方法的有效性。  相似文献