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911.
Generalized Stewart-Gough platforms and their direct kinematics 总被引:5,自引:0,他引:5
In this paper, we introduce the generalized Stewart-Gough platform (GSP) consisting of two rigid bodies connected with six distance and/or angular constraints between six pairs of points, lines, and/or planes in the base and the moving platform, respectively. We prove that there exist 3850 possible forms of GSPs. We give the upper bounds for the number of solutions of the direct kinematics for all the GSPs. We also obtain closed-form solutions and the best upper bounds of real solutions of the direct kinematics for a class of 1120 GSPs. 相似文献
912.
913.
Synthesis, Structure and Characterization of Y-Al-Cr Red Pigment 相似文献
914.
Hongbin Zhang Chunguang Li Xiaofeng Liao 《IEEE transactions on systems, man, and cybernetics. Part B, Cybernetics》2006,36(3):685-698
This paper presents a novel approach to stability analysis of a fuzzy large-scale system in which the system is composed of a number of Takagi-Sugeno (T-S) fuzzy subsystems with interconnections. The stability analysis is based on Lyapunov functions that are continuous and piecewise quadratic. It is shown that the stability of the fuzzy large-scale systems can be established if a piecewise Lyapunov function can be constructed, and, moreover, the function can be obtained by solving a set of linear matrix inequalities (LMIs) that are numerically feasible. It is also demonstrated via a numerical example that the stability result based on the piecewise quadratic Lyapunov functions is less conservative than that based on the common quadratic Lyapunov functions. The H/sub /spl infin// controllers can also be designed by solving a set of LMIs based on these powerful piecewise quadratic Lyapunov functions. 相似文献
915.
The reliability of general vague fault-tree analysis on weapon systems fault diagnosis 总被引:2,自引:0,他引:2
J.-R. Chang K.-H. Chang S.-H. Liao C.-H. Cheng 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2006,10(7):531-542
An algorithm of vague fault-tree analysis is proposed in this paper to calculate fault interval of system components from
integrating expert's knowledge and experience in terms of providing the possibility of failure of bottom events. We also modify
Tanaka et al's definition and extend the new usage on vague fault-tree analysis in terms of finding most important basic system
component for managerial decision-making. In numerical verification, the fault of automatic gun is presented as a numerical
example. For advanced experiment, a fault tree for the reactor protective system is adopted as simulation example and we compare
the results with other methods. This paper also develops vague fault tree decision support systems (VFTDSS) to generate fault-tree,
fault-tree nodes, then directly compute the vague fault-tree interval, traditional reliability, and vague reliability interval. 相似文献
916.
Sliding simulation for adhesion problems in micro gear trains based on an atomistic simplified model
The objective of this research work is to provide a systematic method to perform molecular dynamics simulation or evaluation for adhesion of micro/nano gear train during sliding friction in MEMS. In this paper, molecular dynamics simulations of adhesion problems in micro gear train are proposed. The perfect MEMS gear train model is very complicated by considering the computing time. A simplified model to simulate surface sliding between metals by molecular dynamics (MD) is proposed because the surface property is a dominant factor for the performance of gear systems. Based on analysis of sliding friction and the transmitting characteristics of micro gear train, a model is established by utilizing the Morse potential function. The Verlet algorithm is employed to solve atom trajectories. The simulation results show that adhesion tends to occur between two micro gears after certain cycles and such adhesion accounts for the friction force and the temperature increase. The simulation results are in consistence with the experimental results in the literature. The model is meaningful to prolong the lifetime of micro gear train by selecting proper parameters. 相似文献
917.
印鉴分割是正确识别真假印鉴的关键问题,本文给出了一种新的印鉴图像分割算法。该算法基于样本章(印鉴)和待验章(印鉴)在具有相同的笔划宽度时,分割效果最佳,最利于真假印鉴的识别。选定一定范围的灰度值作为可能的阈值,从中选 出使待验章和样本章的笔划宽度相差最小的阈值作为最佳阈值。对位于待验章和样本章的交集中的边缘点分别在待验章和样本章中求水平和垂直方向上的笔划宽度,并且仅取宽度差最小的一个方向上的宽度差,很好地避免了印泥的浓淡、盖印时用力的深浅、印泥污染、笔划断裂和分裂带来的干扰。实验和实践证明,该方法分割效果好,并具有很好的稳定性,在识别真假印鉴的实践中得到了很好的应用。 相似文献
918.
通过在opnet6.0下进行计算机仿真实验及数据分析,研究Diffserv网络中AF业务类间和AF业务类里分别在欠载,过载情况下带宽分配的公平性问题,发现AF类间有较好的公平性,而在AF类里,受RTT,TCP连接数目,非响应流等因素的影响,并没有较好的带宽分配公平性。 相似文献
919.
面向空间数据库引擎的扩充数据模型及其操纵语言GSQL 总被引:9,自引:3,他引:9
面向空间数据库引擎的扩充数据模型将点、线、面等几何数据类型作为系统的基本数据类型,其操纵语言GSQL在标准SQL语言基础上支持几何数据和属性数据的定义、检索、存储和管理。关系数据库元数据表提供了对象—关系模型转换接口。 相似文献
920.
遗传算法中,分别以在、离线性能表征算法的进行性能和收敛性能[1],两者是一对矛盾体.在算法进行的早期,人们希望算法有较好的在线性能,以便能快速地搜索到最优点的附近.否则便会出现算法过早收敛的情况,谓之“早熟”.在群体演化的后期,很可能会出现下列情况:个体适应度之间的差值比群体最小适应度相差若干个数量级,此时群体演化的速度会非常慢,甚至很多代也不会达到最优点. 遗传算法的作用原理用模式理论能得到很好的解释.根据模式理论,群体中第j个个体通常以概率pj=fj/∑fj的概率被选择复制.若包含于群体中的某模式H在当前代中有M(H,T)个代表个体,则在下一代中此模式的代表个体的期望值将为 相似文献