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Oscillation frequency of simplified arterial tubes

Hui AN, Fan HE, Lingxia XING, Xiaoyang LI

《机械工程前沿（英文）》 2009年 第4卷 第3期   页码 300-304 doi: 10.1007/s11465-009-0038-5

摘要： To construct the spatial kinetic equation of an arterial tube and obtain its radial natural frequency, a linear-elastic and small deformation condition is assumed. The theoretical analysis is first presented and the finite element method is then used to numerically simulate the spatial kinematics. The results show that the first-order frequency is 15.8 Hz and the obtained exact analytical solutions agree well with numerical solutions, which proves that the theoretical analysis and numerical simulation are both correct.

关键词： spatial kinematics     natural frequency     finite element method    

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A comprehensive analysis of a 3-P (Pa) S spatial parallel manipulator

Yuzhe LIU,Liping WANG,Jun WU,Jinsong WANG

《机械工程前沿（英文）》 2015年 第10卷 第1期   页码 7-19 doi: 10.1007/s11465-015-0324-3

摘要：

In this paper, a novel 3-degree of freedom (3-DOF) spatial parallel kinematic machine (PKM) is analyzed. The manipulator owns three main motions (two rotations and one translation) and three concomitant motions (one rotation and two translations). At first, the structure of this spatial PKM is simplified according to the characteristic of each limb. Secondly, the kinematics model of this spatial PKM is set up. In addition, the relationship between the main motions and concomitant motions is studied. The workspaces respectively based on the outputs and inputs are derived and analyzed. Furthermore, the velocity model is put forward. Two indexes based on the velocity model are employed to investigate the performance of this spatial PKM. At last, the output error model can be obtained and simulated. The comprehensive kinematics analysis in this paper is greatly useful for the future applications of this spatial PKM.

关键词： parallel mechanism     concomitant motions     kinematics     workspaces     error model    

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Inverse Kinematics Analysis of General 6R Serial Robot Mechanism Based on Groebner Base

WANG Yan, HANG Lu-bin, YANG Ting-li

《机械工程前沿（英文）》 2006年 第1卷 第1期   页码 115-124 doi: 10.1007/s11465-005-0022-7

摘要：

This study presents a solution for the inverse kinematics problem in serial 6R manipulator. Using only seven equations composed of Duffy s four kinematical equations containing three angles and three corresponding angles identical equations instead of the traditional 14 equations, the authors reduced the inverse kinematics problem in the general 6R manipulator to a univariate polynomial with a minimum degree based on the Groebner Base method. From that, they concluded that the maximum number of the solutions is 16, generally. Also, the mathematics mechanization method can be extended to solve other mechanism problems involving nonlinear equations symbolically.

关键词： identical     manipulator     univariate polynomial     mechanism     traditional    

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Ahybrid biogeography-based optimization method for the inverse kinematics problem of an 8-DOF redundant

Zi-wu REN,Zhen-hua WANG,Li-ning SUN

《信息与电子工程前沿（英文）》 2015年 第16卷 第7期   页码 607-616 doi: 10.1631/FITEE.14a0335

摘要： The redundant humanoid manipulator has characteristics of multiple degrees of freedom and complex joint structure, and it is not easy to obtain its inverse kinematics solution. The inverse kinematics problem of a humanoid manipulator can be formulated as an equivalent minimization problem, and thus it can be solved using some numerical optimization methods. Biogeography-based optimization (BBO) is a new biogeography inspired optimization algorithm, and it can be adopted to solve the inverse kinematics problem of a humanoid manipulator. The standard BBO algorithm that uses traditional migration and mutation operators suffers from slow convergence and prematurity. A hybrid biogeography-based optimization (HBBO) algorithm, which is based on BBO and differential evolution (DE), is presented. In this hybrid algorithm, new habitats in the ecosystem are produced through a hybrid migration operator, that is, the BBO migration strategy and DE/best/1/bin differential strategy, to alleviate slow convergence at the later evolution stage of the algorithm. In addition, a Gaussian mutation operator is adopted to enhance the exploration ability and improve the diversity of the population. Based on these, an 8-DOF (degree of freedom) redundant humanoid manipulator is employed as an example. The end-effector error (position and orientation) and the ‘away limitation level’ value of the 8-DOF humanoid manipulator constitute the fitness function of HBBO. The proposed HBBO algorithm has been used to solve the inverse kinematics problem of the 8-DOF redundant humanoid manipulator. Numerical simulation results demonstrate the effectiveness of this method.

关键词： Inverse kinematics problem     8-DOF humanoid manipulator     Biogeography-based optimization (BBO)     Differential evolution (DE)    

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Analysis of the kinematic characteristics of a high-speed parallel robot with Schönflies motion: Mobility, kinematics

Fugui XIE,Xin-Jun LIU

《机械工程前沿（英文）》 2016年 第11卷 第2期   页码 135-143 doi: 10.1007/s11465-016-0389-7

摘要：

This study introduces a high-speed parallel robot with Schönflies motion. This robot exhibits a promising prospect in realizing high-speed pick-and-place manipulation for packaging production lines. The robot has four identical limbs and a single platform. Its compact structure and single-platform concept provides this robot with good dynamic response potential. A line graph method based on Grassmann line geometry is used to investigate the mobility characteristics of the proposed robot. A generalized Blanding rule is also introduced into this procedure to realize mutual conversion between the line graphs for motions and constraints. Subsequently, the inverse kinematics is derived, and the singularity issue of the robot is investigated using both qualitative and quantitative approaches. Input and output transmission singularity indices are defined based on the reciprocal product in screw theory and the virtual coefficient by considering motion/force transmission performance. Thereafter, the singular loci of the proposed robot with specific geometric parameters are derived. The mobility analysis, inverse kinematics modeling, and singularity analysis conducted in this study are helpful in developing the robot.

关键词： parallel robot     mobility     inverse kinematics     singularity     transmission performance    

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General closed-form inverse kinematics for arbitrary three-joint subproblems based on the product of

《机械工程前沿（英文）》 2022年 第17卷 第2期 doi: 10.1007/s11465-022-0681-7

摘要： The inverse kinematics problems of robots are usually decomposed into several Paden–Kahan subproblems based on the product of exponential model. However, the simple combination of subproblems cannot solve all the inverse kinematics problems, and there is no common approach to solve arbitrary three-joint subproblems in an arbitrary postural relationship. The novel algebraic geometric (NAG) methods that obtain the general closed-form inverse kinematics for all types of three-joint subproblems are presented in this paper. The geometric and algebraic constraints are used as the conditions precedent to solve the inverse kinematics of three-joint subproblems. The NAG methods can be applied in the inverse kinematics of three-joint subproblems in an arbitrary postural relationship. The inverse kinematics simulations of all three-joint subproblems are implemented, and simulation results indicating that the inverse solutions are consistent with the given joint angles validate the general closed-form inverse kinematics. Huaque III minimally invasive surgical robot is used as the experimental platform for the simulation, and a master–slave tracking experiment is conducted to verify the NAG methods. The simulation result shows the inverse solutions and six sets given joint angles are consistent. Additionally, the mean and maximum of the master–slave tracking experiment for the closed-form solution are 0.1486 and 0.4777 mm, respectively, while the mean and maximum of the master–slave tracking experiment for the compensation method are 0.3188 and 0.6394 mm, respectively. The experiments results demonstrate that the closed-form solution is superior to the compensation method. The results verify the proposed general closed-form inverse kinematics based on the NAG methods.

关键词： inverse kinematics     Paden–Kahan subproblems     three-joint subproblems     product of exponential     closed-form solution    

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Fast forward kinematics algorithm for real-time and high-precision control of the 3-RPS parallel mechanism

Yue WANG, Jingjun YU, Xu PEI

《机械工程前沿（英文）》 2018年 第13卷 第3期   页码 368-375 doi: 10.1007/s11465-018-0519-5

摘要：

A new forward kinematics algorithm for the mechanism of 3-RPS (R: Revolute; P: Prismatic; S: Spherical) parallel manipulators is proposed in this study. This algorithm is primarily based on the special geometric conditions of the 3-RPS parallel mechanism, and it eliminates the errors produced by parasitic motions to improve and ensure accuracy. Specifically, the errors can be less than 10-6 . In this method, only the group of solutions that is consistent with the actual situation of the platform is obtained rapidly. This algorithm substantially improves calculation efficiency because the selected initial values are reasonable, and all the formulas in the calculation are analytical. This novel forward kinematics algorithm is well suited for real-time and high-precision control of the 3-RPS parallel mechanism.

关键词： 3-RPS parallel mechanism     forward kinematics     numerical algorithm     parasitic motion    

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Generation of closed-form inverse kinematics for reconfigurable robots

ZHAO Jie, WANG Weizhong, GAO Yongsheng, CAI Hegao

《机械工程前沿（英文）》 2008年 第3卷 第1期   页码 91-96 doi: 10.1007/s11465-008-0013-6

摘要： For reconfigurable robots, the automatic generation of inverse kinematics is a key problem, because such robots may assume various configurations. In this paper, the screw and product-of-exponentials (POE) formula are used to model the kinematics of reconfigurable robots. The POE formula can be converted to canonical subproblems through decomposition and adjoint transformation. Three classes and 28 types of subproblems containing geometric or algebraic solutions are identified and solved, which can be reused in different configurations. A generalized, decomposable, and reusable approach for close-form inverse kinematics of reconfigurable robots is developed based on POE and subproblems. The effectiveness of this method is shown in an example.

关键词： different     effectiveness     generation     reconfigurable     algebraic    

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Soil spatial variability impact on the behavior of a reinforced earth wall

Adam HAMROUNI, Daniel DIAS, Badreddine SBARTAI

《结构与土木工程前沿（英文）》 2020年 第14卷 第2期   页码 518-531 doi: 10.1007/s11709-020-0611-x

摘要： This article presents the soil spatial variability effect on the performance of a reinforced earth wall. The serviceability limit state is considered in the analysis. Both cases of isotropic and anisotropic non-normal random fields are implemented for the soil properties. The Karhunen-Loève expansion method is used for the discretization of the random field. Numerical finite difference models are considered as deterministic models. The Monte Carlo simulation technique is used to obtain the deformation response variability of the reinforced soil retaining wall. The influences of the spatial variability response of the geotechnical system in terms of horizontal facing displacement is presented and discussed. The results obtained show that the spatial variability has an important influence on the facing horizontal displacement as well as on the failure probability.

关键词： reinforced earth wall     geosynthetic     random field     spatial variability     Monte Carlo simulation    

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Industrial eco-efficiency and its spatial-temporal differentiation in China

Wei YANG, Fengjun JIN, Chengjin WANG, Chen LV

《环境科学与工程前沿（英文）》 2012年 第6卷 第4期   页码 559-568 doi: 10.1007/s11783-012-0400-4

摘要： The aim of this paper is to study the spatial-temporal differentiation of industrial eco-efficiency in China. Using methods based on the data envelopment analysis (DEA) model and exploratory spatial data analysis (ESDA) and data from 1985, 1995, 2005, and 2008 of 30 provinces in China, the spatial-temporal pattern changes in industrial eco-efficiency are discussed. The results show that: first, the patterns of industrial eco-efficiency are dominated by clustering of relatively low efficiency provinces; second, spatial relationships between the industrial eco-efficiencies of different provinces changed slightly throughout the period and the provinces persistently exhibit spatial concentration of relatively low industrial eco-efficiency; finally, there is an obvious trend in the polarization of industrial eco-efficiency, i.e., the higher level spatial units are concentrated in eastern China, and the lower level spatial units are mainly in western and central China.

关键词： industrial eco-efficiency     data envelopment analysis (DEA) model     exploratory spatial data analysis (ESDA)    

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Border-search and jump reduction method for size optimization of spatial truss structures

Babak DIZANGIAN, Mohammad Reza GHASEMI

《结构与土木工程前沿（英文）》 2019年 第13卷 第1期   页码 123-134 doi: 10.1007/s11709-018-0478-2

摘要： This paper proposes a sensitivity-based border-search and jump reduction method for optimum design of spatial trusses. It is considered as a two-phase optimization approach, where at the first phase, the first local optimum is found by few analyses, after the whole searching space is limited employing an efficient random strategy, and the second phase involves finding a sequence of local optimum points using the variables sensitivity with respect to corresponding values of constraints violation. To reach the global solution at phase two, a sequence of two sensitivity-based operators of border-search operator and jump operator are introduced until convergence is occurred. Sensitivity analysis is performed using numerical finite difference method. To do structural analysis, a link between open source software of OpenSees and MATLAB was developed. Spatial truss problems were attempted for optimization in order to show the fastness and efficiency of proposed technique. Results were compared with those reported in the literature. It shows that the proposed method is competitive with the other optimization methods with a significant reduction in number of analyses carried.

关键词： optimum design     sensitivity analysis     reduction method     spatial trusses     OpenSees    

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Abundance, spatial distribution, and physical characteristics of microplastics in stormwater detention

《环境科学与工程前沿（英文）》 2023年 第17卷 第10期 doi: 10.1007/s11783-023-1724-y

摘要： Despite extensive research on microplastics (MP) in marine environments, little is known about MP abundance and transport in terrestrial systems. There is, therefore, still little understanding of the main mechanisms driving the substantial transport of MP across different environmental compartments. Storm events can transport MP beyond boundaries, such as from the land to groundwater or the ocean, as has already been discovered for organic carbon transport. Urban stormwater detention ponds are suitable environments to study the impact of stormwater on the environmental fate and transport of MP. Herein, we investigate the longitudinal and vertical distribution of MP within two detention ponds with different physical characteristics. Soil samples were collected at various locations and from multiple depths (surface and subsurface layers) for measuring MP concentrations using fluorescence microscopy. Our findings show that MP are retained more near the inlet of the ponds, and MP of larger sizes were found more abundantly near inlets than outlets. We also found that MP mass and sizes decrease from surface soil to subsurface soil. In the pond, where vegetation (grass root network) was more considerable, MP were found more evenly distributed along the depth. In terms of shape, the fragments were the most abundant MP shape.

关键词： Microplastic     Environmental transport     Soil pollution     Stormwater     Detention ponds    

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Inverse kinematics analysis and numerical control experiment for PRS-XY style hybrid machining tool

JIA Dongyong, ZHANG Jianmin, SUN Hongchang, NIU Zhigang

《机械工程前沿（英文）》 2007年 第2卷 第2期   页码 235-238 doi: 10.1007/s11465-007-0041-7

摘要： This paper analyzed the inverse kinematics for the new Parallel rotate slider- axes (PRS-) style hybrid machining tool and educed the five axes linkage inverse kinematics transform formula on the basis of the coordinates of the and virtual axes. The program for the PRS-XY style hybrid machining tool in accordance with the program manner for the common numerical control (NC) machine tool was made. The results of the experiments prove that the inverse kinematics transform formula is correct.

关键词： numerical     accordance     transform formula     virtual     slider-    

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Spatial prediction of soil contamination based on machine learning: a review

《环境科学与工程前沿（英文）》 2023年 第17卷 第8期 doi: 10.1007/s11783-023-1693-1

摘要：

● A review of machine learning (ML) for spatial prediction of soil contamination.

关键词： Soil contamination     Machine learning     Prediction     Spatial distribution    

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Optimization of spatial structure designs of control rod using Monte Carlo code RMC

《能源前沿（英文）》 2021年 第15卷 第4期   页码 974-983 doi: 10.1007/s11708-021-0769-5

摘要： Control rod is the most important approach to control reactivity in reactors, which is currently a cluster of pins filled with boron carbide (B4C). In this case, neutrons are captured in the outer region, and thus the inner absorber is inefficient. Moreover, the lifetime of the control rod is challenged due to the high reactivity worth loss resulted from the excessive degradation of B4C in the high flux area. In this work, some control rod designs are proposed with optimized spatial structures including the spatially mixed rod, radially moderated rod, and composite control rod with small-sized pins. The control rod worth and effective absorption cross section of these designs are computed using the Monte Carlo code RMC. A long-time depletion calculation is conducted to evaluate their burnup stability. For the spatially mixed rod, rare-earth absorbers are combined with B4C in spatial structure. Compared with the homogenous B4C rod, mixed designs ensure more sufficient reactivity worth in the lifetime of the reactor. The minimum reactivity loss at the end of the cycle is only 1.8% from the dysprosium titanate rod, while the loss for pure B4C rod is nearly 12%. For the radially moderated design, a doubled neutronic efficiency is achieved when the volume ratio of moderator equals approximately 0.3, while excessive moderating may lead to the failure of control rods. The control rod with small-sized pins processes an enhanced safety performance and saves the investment in absorbers. The rod worth can be further enhanced by introducing small moderator pins, and the reactivity loss caused by the reduction of absorbers is sustainable.

关键词： control rod     optimized spatial structure     neutronic performance     burnup stability    

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标题 作者 时间 类型 操作

Oscillation frequency of simplified arterial tubes

Hui AN, Fan HE, Lingxia XING, Xiaoyang LI

期刊论文

A comprehensive analysis of a 3-P (Pa) S spatial parallel manipulator

Yuzhe LIU,Liping WANG,Jun WU,Jinsong WANG

期刊论文

Inverse Kinematics Analysis of General 6R Serial Robot Mechanism Based on Groebner Base

WANG Yan, HANG Lu-bin, YANG Ting-li

期刊论文

Ahybrid biogeography-based optimization method for the inverse kinematics problem of an 8-DOF redundant

Zi-wu REN,Zhen-hua WANG,Li-ning SUN

期刊论文

Analysis of the kinematic characteristics of a high-speed parallel robot with Schönflies motion: Mobility, kinematics

Fugui XIE,Xin-Jun LIU

期刊论文

General closed-form inverse kinematics for arbitrary three-joint subproblems based on the product of

期刊论文

Fast forward kinematics algorithm for real-time and high-precision control of the 3-RPS parallel mechanism

Yue WANG, Jingjun YU, Xu PEI

期刊论文

Generation of closed-form inverse kinematics for reconfigurable robots

ZHAO Jie, WANG Weizhong, GAO Yongsheng, CAI Hegao

期刊论文

Soil spatial variability impact on the behavior of a reinforced earth wall

Adam HAMROUNI, Daniel DIAS, Badreddine SBARTAI

期刊论文

Industrial eco-efficiency and its spatial-temporal differentiation in China

Wei YANG, Fengjun JIN, Chengjin WANG, Chen LV

期刊论文

Border-search and jump reduction method for size optimization of spatial truss structures

Babak DIZANGIAN, Mohammad Reza GHASEMI

期刊论文

Abundance, spatial distribution, and physical characteristics of microplastics in stormwater detention

期刊论文

Inverse kinematics analysis and numerical control experiment for PRS-XY style hybrid machining tool

JIA Dongyong, ZHANG Jianmin, SUN Hongchang, NIU Zhigang

期刊论文

Spatial prediction of soil contamination based on machine learning: a review

期刊论文

Optimization of spatial structure designs of control rod using Monte Carlo code RMC

期刊论文