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Interconverting Models of Gray Matrix and Geographic Coordinates Based on Space Analytic Geometry 被引量:1
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作者 Ni Zhan Liang Lin Ling Lou 《Applied Mathematics》 2013年第1期46-51,共6页
With the progress and development of science, the synchronous satellite as the high-tech product is taken something more and more seriously by all countries. Converting gray value matrix into geographic coordinates be... With the progress and development of science, the synchronous satellite as the high-tech product is taken something more and more seriously by all countries. Converting gray value matrix into geographic coordinates becomes more and more important. This paper establishes the models for interconverting row and column of gray value matrix which detected by the infrared detectors on synchronous satellites and geographic coordinates based on the related theorems and properties of space analytic geometry. We draw satellite cloud image with the data of gray matrix in MATLAB, convert coastline’s latitude and longitude coordinates into row and column coordinates of a gray matrix according via these models when the sub-satellite point’s row and column coordinates and geographic coordinates are given, then add coast-lines to the original satellite cloud image with the transformation data. We find that coast-lines completely match with the bump characteristics of satellite cloud image, and that verify the correctness of the models. 展开更多
关键词 Space ANALYTIC Geometry Satellite Cloud Image GEOGRAPHIC coordinates GRAY Value matrix COASTLINE
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Coordinatively unsaturated sites in zeolite matrix: Construction and catalysis 被引量:6
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作者 Weijie Li Lanan Sun +3 位作者 Linjun Xie Xin Deng Naijia Guan Landong Li 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第9期1255-1281,共27页
Zeolites with ordered porous structure of molecular size are widely employed as commercial adsorbents and catalysts.On the other hand,the zeolite matrix is regarded as an ideal scaffold for hosting coordinatively unsa... Zeolites with ordered porous structure of molecular size are widely employed as commercial adsorbents and catalysts.On the other hand,the zeolite matrix is regarded as an ideal scaffold for hosting coordinatively unsaturated sites.Remarkable achievements have been made dealing with the construction,characterization and catalytic applications of coordinatively unsaturated sites in zeolite matrix.Herein,a literature overview of recent progresses on this important topic is presented from the specific view of coordination chemistry.Different strategies to construction coordinatively unsaturated sites in zeolite matrix,in zeolite framework or extraframework positions,are first introduced and their characteristics are compared.Then,spectroscopic techniques to determine the existing states of cation sites and their transformations in zeolite matrix are discussed.In the last section,the catalytic applications of coordinatively unsaturated sites in zeolite matrix for various important chemical transformations are summarized. 展开更多
关键词 coordinatively unsaturated sites Zeolite matrix CONSTRUCTION Characterization CATALYSIS
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Geometric Deviation Modeling by Kinematic Matrix Based on Lagrangian Coordinate 被引量:1
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作者 LIU Weidong HU Yueming +1 位作者 LIU Yu DAI Wanyi 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2015年第5期1056-1066,共11页
Typical representation of dimension and geometric accuracy is limited to the self-representation of dimension and geometric deviation based on geometry variation thinking, yet the interactivity affection of geometric ... Typical representation of dimension and geometric accuracy is limited to the self-representation of dimension and geometric deviation based on geometry variation thinking, yet the interactivity affection of geometric variation and gesture variation of multi-rigid body is not included. In this paper, a kinematic matrix model based on Lagrangian coordinate is introduced, with the purpose of unified model for geometric variation and gesture variation and their interactive and integrated analysis. Kinematic model with joint, local base and movable base is built. The ideal feature of functional geometry is treated as the base body; the fitting feature of functional geometry is treated as the adjacent movable body; the local base of the kinematic model is fixed onto the ideal geometry, and the movable base of the kinematic model is fixed onto the fitting geometry. Furthermore, the geometric deviation is treated as relative location or rotation variation between the movable base and the local base, and it's expressed by the Lagrangian coordinate. Moreover, kinematic matrix based on Lagrangian coordinate for different types of geometry tolerance zones is constructed, and total freedom for each kinematic model is discussed. Finally, the Lagrangian coordinate library, kinematic matrix library for geometric deviation modeling is illustrated, and an example of block and piston fits is introduced. Dimension and geometric tolerances of the shaft and hole fitting feature are constructed by kinematic matrix and Lagrangian coordinate, and the results indicate that the proposed kinematic matrix is capable and robust in dimension and geometric tolerances modeling. 展开更多
关键词 geometry deviation geometry deviation representation kinematic matrix Lagrangian coordinate virtual joint
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Expression of strain tensor in orthogonal curvilinear coordinates
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作者 Xuyan Liu Yingfeng Ji Quanqiang Liang 《Geodesy and Geodynamics》 2010年第1期48-56,共9页
Based on an analysis of connotation and extension of the concept of the orthogonal curvilinear coordinates, we have deduced a platform of strain tensor expression of Cartesian coordinates, which turns out to be a func... Based on an analysis of connotation and extension of the concept of the orthogonal curvilinear coordinates, we have deduced a platform of strain tensor expression of Cartesian coordinates, which turns out to be a function of Lame coefficient and unit vector. By using transform matrix between Cartesian coordinates and orthogonal eurvilinear coordinates, we have deduced a mathematical expression for correcting displacement vector differential in orthogonal curvilinear coordinates, and given a general expression of strain tensor in orthogonal curvilinear coordinates. 展开更多
关键词 Orthogonal Curvilinear coordinates OCC Cartesian coordinates strain tensor transformation matrix universal expression
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基于耦合协调的绿色雨水基础设施供需分析
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作者 陈亦淳 《城市建筑》 2025年第2期125-128,共4页
本研究提出了一个定量框架,通过耦合协调模拟模型来确定绿色雨水基础设施(GSI)的优先领域,并检验广东、香港地区和澳门大湾区的复杂供需匹配关系。利用网络参考图绘制邻近矩阵进行分析,通过聚类多个乡镇来解释供求关系的评估聚类图。其... 本研究提出了一个定量框架,通过耦合协调模拟模型来确定绿色雨水基础设施(GSI)的优先领域,并检验广东、香港地区和澳门大湾区的复杂供需匹配关系。利用网络参考图绘制邻近矩阵进行分析,通过聚类多个乡镇来解释供求关系的评估聚类图。其中,90%的乡镇处于耦合协调不平衡状态。同时,根据聚类分析可以为同一种需求类型提一种供供给方式,为规划者在不同环境不同功能中提供GSI的战略性规划。 展开更多
关键词 绿色雨水基础设施 供需 耦合协调模型 邻近矩阵分析 城镇
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Three Types of Spatial Function Zoning in Key Ecological Function Areas Based on Ecological and Economic Coordinated Development: A Case Study of Tacheng Basin, China 被引量:3
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作者 WANG Guiling YANG Degang +2 位作者 XIA Fuqiang ZHONG Ruisen XIONG Chuanhe 《Chinese Geographical Science》 SCIE CSCD 2019年第4期689-699,共11页
Three types of spatial function zoning is an effective measure for regional environmental protection and orderly development.For ecological and economic coordinated development, spatial function zones should be divide... Three types of spatial function zoning is an effective measure for regional environmental protection and orderly development.For ecological and economic coordinated development, spatial function zones should be divided scientifically to clear its direction of development and protection. Therefore, based on ecological constraints, a beneficial discussion would be about the key ecological function areas adopting the concept of ecological protection restriction and supporting socioeconomic development for spatial function zoning. In this paper, the researchers, taking Tacheng Basin, Xinjiang of China as an example, choose township as basic research unit and set up an evaluation index system from three aspects, namely, ecological protection suitability, agricultural production suitability, and urban development suitability, which are analyzed by using spatial analysis functions and exclusive matrix method. The results showed that: 1) This paper formed a set of multilevel evaluation index systems for three types of spatial function zoning of the key ecological function areas based on a novel perspective by scientifically dividing Tacheng Basin into ecological space, agricultural space, and urban space,which realized the integration and scientific orientation for spatial function at the township scale. 2) Under the guidance of three types of spatial pattern, the functional orientation and suggestions of development and protection was clearly defined for ecological protection zones,ecological economic zones, agricultural production zones, and urban development zones. 3) A new idea of space governance is provided to promote the coordinated and sustainable development between ecology and economy, which can break the traditional mode of thinking about regional economic development, and offers a scientific basis and reference for macro decision-making. 展开更多
关键词 KEY ecological FUNCTION areas township scale SPATIAL FUNCTION ZONING mutual EXCLUSION matrix method coordination of ECOLOGY and development Tacheng Basin China
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Correlation of coordinate transformation parameters 被引量:1
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作者 Du Lan Zhang Hanwei +1 位作者 Zhou Qingyong Wang Ruopu 《Geodesy and Geodynamics》 2012年第1期34-38,共5页
Coordinate transformation parameters between two spatial Cartesian coordinate systems can be solved from the positions of non-colinear corresponding points. Based on the characteristics of translation, rotation and zo... Coordinate transformation parameters between two spatial Cartesian coordinate systems can be solved from the positions of non-colinear corresponding points. Based on the characteristics of translation, rotation and zoom components of the transformation, the complete solution is divided into three steps. Firstly, positional vectors are regulated with respect to the centroid of sets of points in order to separate the translation compo- nents. Secondly, the scale coefficient and rotation matrix are derived from the regulated positions independent- ly and correlations among transformation model parameters are analyzed. It is indicated that this method is applicable to other sets of non-position data to separate the respective attributions for transformation parameters. 展开更多
关键词 coordinate transformation model Bursa model orthnormal matrix singular value decomposition (SVD) CORRELATION
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Adaptive neural network control for coordinated motion of a dual-arm space robot system with uncertain parameters 被引量:1
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作者 郭益深 陈力 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2008年第9期1131-1140,共10页
Control of coordinated motion between the base attitude and the arm joints of a free-floating dual-arm space robot with uncertain parameters is discussed. By combining the relation of system linear momentum conversati... Control of coordinated motion between the base attitude and the arm joints of a free-floating dual-arm space robot with uncertain parameters is discussed. By combining the relation of system linear momentum conversation with the Lagrangian approach, the dynamic equation of a robot is established. Based on the above results, the free-floating dual-arm space robot system is modeled with RBF neural networks, the GL matrix and its product operator. With all uncertain inertial system parameters, an adaptive RBF neural network control scheme is developed for coordinated motion between the base attitude and the arm joints. The proposed scheme does not need linear parameterization of the dynamic equation of the system and any accurate prior-knowledge of the actual inertial parameters. Also it does not need to train the neural network offline so that it would present real-time and online applications. A planar free-floating dual-arm space robot is simulated to show feasibility of the proposed scheme. 展开更多
关键词 flee-floating dual-arm space robot RBF neural network GL matrix andits product operator coordinated motion adaptive control
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Disturbance observer based finite-time coordinated attitude tracking control for spacecraft on SO(3) 被引量:1
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作者 SHI Zhen XIE Yaen +3 位作者 DENG Chengchen ZHAO Kun HE Yushan HAO Yong 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2020年第6期1274-1285,共12页
To solve the problem of attitude synchronization control for spacecraft formation flying(SFF)suffering from external disturbances under a directed communication topology,a sliding mode disturbance observer(SMDO)based ... To solve the problem of attitude synchronization control for spacecraft formation flying(SFF)suffering from external disturbances under a directed communication topology,a sliding mode disturbance observer(SMDO)based on the finite-time control strategy is developed to observe the time-varying external disturbance via estimating the upper bound of its first derivative.Meanwhile,the rotation matrix is employed to describe the attitude of SFF for the purpose of the avoidance of singularity and unwinding phenomenon.As for the attitude synchronization and the tracking control architecture,a sliding mode surface(SMS)is given such that the control objective can be achieved.The effectiveness and the validity of the proposed method are elaborated via theoretical analysis and numerical simulations. 展开更多
关键词 coordinated attitude control disturbance observer rotation matrix attitude synchronization control
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Research and Design of Coordinated Control Strategy for Smart Electromechanical Actuator System 被引量:1
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作者 HAO Zhenyang ZHANG Qiyao +2 位作者 CHEN Huajie CAO Xin MIAO Wei 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2022年第5期507-520,共14页
In order to improve the frequency response and anti-interference characteristics of the smart electromechanical actuator(EMA)system,and aiming at the force fighting problem when multiple actuators work synchronously,a... In order to improve the frequency response and anti-interference characteristics of the smart electromechanical actuator(EMA)system,and aiming at the force fighting problem when multiple actuators work synchronously,a multi input multi output(MIMO)position difference cross coupling control coordinated strategy based on double‑closed-loop load feedforward control is proposed and designed.In this strategy,the singular value method of return difference matrix is used to design the parameter range that meets the requirements of system stability margin,and the sensitivity function and the H_(∞)norm theory are used to design and determine the optimal solution in the obtained parameter stability region,so that the multi actuator system has excellent synchronization,stability and anti-interference.At the same time,the mathematical model of the integrated smart EMA system is established.According to the requirements of point-to-point control,the controller of double-loop control and load feedforward compensation is determined and designed to improve the frequency response and anti-interference ability of single actuator.Finally,the 270 V high-voltage smart EMA system experimental platform is built,and the frequency response,load feedforward compensation and coordinated control experiments are carried out to verify the correctness of the position difference cross coupling control strategy and the rationality of the parameter design,so that the system can reach the servo control indexes of bandwidth 6 Hz,the maximum output force 20000 N and the synchronization error≤0.1 mm,which effectively solves the problem of force fighting. 展开更多
关键词 smart electromechanical actuator(EMA) force fighting coordinated control strategy cross coupling control singular value method of return difference matrix sensitivity H∞norm control
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Investigations of the electron paramagnetic resonance parameters and the tetragonal local structure for (VCl_6)^(4-) coordination complex in MCl:V^(2+) (M=Na,K,Rb) systems
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作者 祁林 邝小渝 +2 位作者 柴瑞鹏 段美玲 张彩霞 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第4期1586-1593,共8页
By simulating the electron paramagnetic resonance (EPR) and optical spectra on the basis of the 120 × 120 complete energy matrix, this paper determines the local lattice structure parameters R1 and R2 for MCl... By simulating the electron paramagnetic resonance (EPR) and optical spectra on the basis of the 120 × 120 complete energy matrix, this paper determines the local lattice structure parameters R1 and R2 for MCl:V2+ (M=Na, K, Rb) systems at 77K, 195 K and RT (room temperature 295 K or 302 K), respectively. The theoretical results indicate that there exists a compressed distortion in MCl:V2+ systems. Meanwhile, it finds that the structure parameters R1, R2 and |△R|( = R1 - R2) increase with the rising temperature. Subsequently, from the analysis it concludes that the relation of EPR parameter D vs. △R is approximately linear. Finally, the effects of orbital reduction factor k on the g factors for the three systems have been discussed. 展开更多
关键词 complete energy matrix EPR parameters (VCl6)4- coordination complex local structure
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Light pen whole space coordinate measuring system based on a tracking turntable
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作者 WANG Sen LIU Shugui MAO Qing 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2021年第4期379-389,共11页
Light pen coordinate measuring system(LPCMS)is a kind of portable coordinate measuring technique based on vision metrology.In classical LPCMS,the measuring range is limited to the camera’s field of view.To overcome t... Light pen coordinate measuring system(LPCMS)is a kind of portable coordinate measuring technique based on vision metrology.In classical LPCMS,the measuring range is limited to the camera’s field of view.To overcome this defect,a new LPCMS is designed in this paper to fulfil whole space coordinate measurement.The camera is installed on a turntable instead of a tripod,so that the camera can rotate to track the movement of the light pen.The new system can be applied to large scale onsite measurement,and therefore it notably extends the application of LPCMS.To guarantee the accuracy of the new system,a method to calibrate the parameters of the tracking turntable is also proposed.Fixing the light pen at a stationary position,and changing the azimuth angles of the turntable’s two shafts,so that the camera can capture the images of the light pen from different view angles.According to the invariant spatial relationship between the camera and the pedestal of the tracking turntable,a system of nonlinear equations can be established to solve the parameters of the turntable.Experimental results show that the whole space coordinate measuring accuracy of the new system can reach 0.25 mm within 10 m.It can be concluded that the newly designed system can significantly expand the measuring range of LPCMS without losing too much accuracy. 展开更多
关键词 light pen whole space coordinate measuring system tracking turntable vision metrology parameter calibration homogeneous coordinate transformation matrix
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The Use of the Matrix Method for the Study of Human Motion:Theory and Applications
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作者 Jesse A.Fisk Savio L-Y.Woo 《生物医学工程学杂志》 EI CAS CSCD 2003年第3期375-383,共9页
Kinematics has been successfully used to describe body motion without reference to the kinetics (or forces causing the motion). In this article, both the theory and applications of the matrix method are provided to de... Kinematics has been successfully used to describe body motion without reference to the kinetics (or forces causing the motion). In this article, both the theory and applications of the matrix method are provided to describe complex human motion. After the definition of a Cartesian coordinate frame is introduced, the description of transformations between multiple coordinate frames is given; the decomposition of a transformation matrix into anatomical joint motion parameters (e.g. Euler angles) is then explained. The advantages of the matrix method are illustrated by three examples related to biomechanical studies. The first describes a reaching and grasping task in which matrix transformations are applied to position the hand with respect to an object during grasping. The second example demonstrates the utility of the matrix method in revealing the coupling motion of the wrist between flexion-extension and radial-ulnar deviation. The last example highlights the indispensable use of the matrix method for the study of knee biomechanics, including the description of knee joint kinematics during functional activities and determination of in-situ ligament forces using robotic technology, which has advanced our understanding of the functions of the cruciate ligaments to knee joint kinematics. It is hoped that the theoretical development and biomechanical application examples will help the readers apply the matrix method to research problems related to human motion. 展开更多
关键词 人类运动 矩阵 运动学 生物医学
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The Coordinate-Free Prediction in Finite Populations with Correlated Observations
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作者 Silvia N. Elian 《Open Journal of Statistics》 2017年第2期182-193,共12页
In this paper, we got the best linear unbiased predictor of any linear function of the elements of a finite population under coordinate-free models. The optimal predictor of these quantities was obtained in an earlier... In this paper, we got the best linear unbiased predictor of any linear function of the elements of a finite population under coordinate-free models. The optimal predictor of these quantities was obtained in an earlier work considering models with a known diagonal covariance matrix. We extended this result assuming any known covariance matrix. It is shown that in the particular case of the coordinatized models, this general predictor coincides with the optimal predictor of the total population under a regression super population model with correlated observations. 展开更多
关键词 coordinate-Free Models Best Linear UNBIASED PREDICTOR COVARIANCE matrix ORTHOGONAL PROJECTION
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Design of Tracking Controller for Coordinated Boiler-turbine Control System Based on Fuzzy Lyapunov Functions
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作者 LIU Shanjian SHEN Jiong +2 位作者 LIU Xichui LI Yiguo WU Jie 《中国电机工程学报》 EI CSCD 北大核心 2013年第11期I0014-I0014,共1页
关键词 LYAPUNOV 发电锅炉 汽轮机 控制器设计 控制系统 非线性系统 PID控制 跟踪
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加权区间值犹豫模糊集的群决策方法
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作者 朱国成 张娟 赵瑞华 《喀什大学学报》 2024年第3期1-11,共11页
为了在区间值犹豫模糊集(IVHFS)中体现出决策专家的重要性,把所有评审专家的综合权重注入IVHFS中,进而定义了加权区间值犹豫模糊集(WIVHFS).将WIVHFS用三维点坐标(由区间值隶属度的中位数、区间值隶属度的清晰度以及评审专家综合权重构... 为了在区间值犹豫模糊集(IVHFS)中体现出决策专家的重要性,把所有评审专家的综合权重注入IVHFS中,进而定义了加权区间值犹豫模糊集(WIVHFS).将WIVHFS用三维点坐标(由区间值隶属度的中位数、区间值隶属度的清晰度以及评审专家综合权重构成)进行刻画,在此基础上给出了加权区间值犹豫模糊元(WIVHFE)的相关运算;基于WIVHFE的相关运算采用熵值法计算测评准则客观权重,利用0-1优先关系矩阵来获取任意2个备选方案的总测评准则权重优势值与总测评准则权重劣势值,并依据二者之间的大小排序方案.最后,通过一个具体案例说明了文中理论与方法的可行性. 展开更多
关键词 加权区间值犹豫模糊集 加权区间值犹豫模糊元 群决策方法 三维点坐标 0-1优先关系矩阵
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基于奇异值分解张拉整体结构找形方法 被引量:1
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作者 罗阿妮 曹紫莺 刘贺平 《哈尔滨工程大学学报》 EI CAS CSCD 北大核心 2024年第5期957-963,共7页
张拉整体结构是由一组不连续的受压单元包含于连续受拉单元组成的稳定自平衡结构,为了寻找自平衡状态下的构型,引入奇异值分解的方法,将寻找张拉整体结构的自平衡构型问题转化为最小奇异值的判定。通过广义节点坐标和构件之间的连接关... 张拉整体结构是由一组不连续的受压单元包含于连续受拉单元组成的稳定自平衡结构,为了寻找自平衡状态下的构型,引入奇异值分解的方法,将寻找张拉整体结构的自平衡构型问题转化为最小奇异值的判定。通过广义节点坐标和构件之间的连接关系建立结构的数学模型;引入力密度的概念,对张拉整体结构进行受力分析,列写包含平衡矩阵的平衡方程;对平衡矩阵进行奇异值分解,利用分解获得的最小奇异值判断平衡方程是否有解,对张拉整体结构是否存在自平衡构型进行初步判定,再依据获得的力密度的均匀性(同组构件力密度大小相等)和正负属性(杆的力密度小于0,索的力密度大于0)对结构自平衡状态进一步判断;通过实例分析对该找形方法的可行性进行了验证,结果表明:该方法可以找到张拉整体结构自平衡构型。本文为寻找自平衡张拉整体结构提供了一种思路。 展开更多
关键词 张拉整体结构 找形方法 节点坐标 连接矩阵 平衡矩阵 平衡方程 奇异值分解 力密度
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泰勒级数准则的船体分段测量数据配准解析解
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作者 杨贵强 王炬成 李瑞 《哈尔滨工程大学学报》 EI CAS CSCD 北大核心 2024年第11期2094-2099,共6页
为提高船体分段测量数据与CAD模型间的配准定位效率,本文给出了一个基于泰勒级数准则的点集配准解析解,直接求解配准变换参数。通过分析最小二乘解析解的求解特点,考虑到配准变换参数的齐次表示问题,引入特征因子构建新的齐次变换矩阵,... 为提高船体分段测量数据与CAD模型间的配准定位效率,本文给出了一个基于泰勒级数准则的点集配准解析解,直接求解配准变换参数。通过分析最小二乘解析解的求解特点,考虑到配准变换参数的齐次表示问题,引入特征因子构建新的齐次变换矩阵,建立配准齐次表示模型。利用泰勒级数展开齐次变换矩阵的最近正交矩阵,得到齐次变换矩阵的无限次估计解。在此基础上,根据配准齐次表示模型的最大化,计算旋转矩阵的近似解析最优解。以理论模型和甲板分段实测数据为例子验证。本文算法的有效性及实用性,为船体分段快速测量分析提供算法依据。 展开更多
关键词 船体分段 精度控制 齐次坐标 泰勒级数 点集配准 解析解 最小二乘 特征因子 最近正交矩阵
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Improved Variable Forgetting Factor Proportionate RLS Algorithm with Sparse Penalty and Fast Implementation Using DCD Iterations
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作者 Han Zhen Zhang Fengrui +2 位作者 Zhang Yu Han Yanfeng Jiang Peng 《China Communications》 SCIE CSCD 2024年第10期16-27,共12页
The proportionate recursive least squares(PRLS)algorithm has shown faster convergence and better performance than both proportionate updating(PU)mechanism based least mean squares(LMS)algorithms and RLS algorithms wit... The proportionate recursive least squares(PRLS)algorithm has shown faster convergence and better performance than both proportionate updating(PU)mechanism based least mean squares(LMS)algorithms and RLS algorithms with a sparse regularization term.In this paper,we propose a variable forgetting factor(VFF)PRLS algorithm with a sparse penalty,e.g.,l_(1)-norm,for sparse identification.To reduce the computation complexity of the proposed algorithm,a fast implementation method based on dichotomous coordinate descent(DCD)algorithm is also derived.Simulation results indicate superior performance of the proposed algorithm. 展开更多
关键词 dichotomous coordinate descent proportionate matrix RLS sparse systems variable forgetting factor
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Systematic Elastostatic Stiffness Model of Over-Constrained Parallel Manipulators Without Additional Constraint Equations
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作者 Chao Yang Wenyong Yu +2 位作者 Wei Ye Qiaohong Chen Fengli Huang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2024年第4期258-276,共19页
The establishment of an elastostatic stiffness model for over constrained parallel manipulators(PMs),particularly those with over constrained subclosed loops,poses a challenge while ensuring numerical stability.This s... The establishment of an elastostatic stiffness model for over constrained parallel manipulators(PMs),particularly those with over constrained subclosed loops,poses a challenge while ensuring numerical stability.This study addresses this issue by proposing a systematic elastostatic stiffness model based on matrix structural analysis(MSA)and independent displacement coordinates(IDCs)extraction techniques.To begin,the closed-loop PM is transformed into an open-loop PM by eliminating constraints.A subassembly element is then introduced,which considers the flexibility of both rods and joints.This approach helps circumvent the numerical instability typically encountered with traditional constraint equations.The IDCs and analytical constraint equations of nodes constrained by various joints are summarized in the appendix,utilizing multipoint constraint theory and singularity analysis,all unified within a single coordinate frame.Subsequently,the open-loop mechanism is efficiently closed by referencing the constraint equations presented in the appendix,alongside its elastostatic model.The proposed method proves to be both modeling and computationally efficient due to the comprehensive summary of the constraint equations in the Appendix,eliminating the need for additional equations.An example utilizing an over constrained subclosed loops demonstrate the application of the proposed method.In conclusion,the model proposed in this study enriches the theory of elastostatic stiffness modeling of PMs and provides an effective solution for stiffness modeling challenges they present. 展开更多
关键词 Parallel manipulator Elastostatic stiffness model matrix structural analysis Subassembly element Independent displacement coordinates
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