资源类型

期刊论文 173

会议视频 6

年份

2023 11

2022 23

2021 16

2020 10

2019 8

2018 6

2017 10

2016 10

2015 10

2014 9

2013 12

2012 3

2011 4

2010 7

2009 5

2008 6

2007 12

2006 5

2005 2

2003 1

展开 ︾

关键词

海上风电 3

能源 3

误差补偿 3

2021全球十大工程成就 2

COVID-19 2

SARS-CoV-2 2

信息技术 2

有限元分析 2

神经网络 2

误差分析 2

ACE2 1

ANSYS 1

BP算法 1

CO2 1

FE-SEA混合法 1

H2S 1

HIV感染孕产妇 1

HY-2卫星 1

LED灯具;加速老化测试;中位寿命;滑动平均误差 1

展开 ︾

检索范围:

排序: 展示方式:

Planet position errors in planetary transmission: Effect on load sharing and transmission error

Miguel IGLESIAS, Alfonso FERNáNDEZ, Ana DE-JUAN, Ramón SANCIBRIáN, Pablo GARCíA

《机械工程前沿(英文)》 2013年 第8卷 第1期   页码 80-87 doi: 10.1007/s11465-013-0362-7

摘要:

In this paper an advanced model of spur gear transmissions developed by the authors is used to study the influence of carrier planet pin hole position errors on the behaviour of the transmission. The model, initially conceived for external gear modeling, has been extended with internal meshing features, and thus increasing its capabilities to include planetary transmission modeling. The new features are presented, along with the summary of the model general approach. The parameters and characteristics of the planetary transmission used in the paper are introduced. The influence of carrier planet pin hole position errors on the planet load sharing is studied, and several static cases are given as examples in order to show the ability of the model. Tangential and radial planet pin hole position errors are considered independently, and the effect of the load level is also taken into account. It is also given attention to the effect on the transmission error of the transmission. Two different configurations for the planetary transmission are used, attending to the fixed or floating condition of the sun, and the differences in terms of load sharing ratio are shown.

关键词: gear     planetary     epicyclic     transmission     load sharing     transmission error    

Mesh relationship modeling and dynamic characteristic analysis of external spur gears with gear wear

《机械工程前沿(英文)》 2022年 第17卷 第1期   页码 9-9 doi: 10.1007/s11465-021-0665-z

摘要: Gear wear is one of the most common gear failures, which changes the mesh relationship of normal gear. A new mesh relationship caused by gear wear affects meshing excitations, such as mesh stiffness and transmission error, and further increases vibration and noise level. This paper aims to establish the model of mesh relationship and reveal the vibration characteristics of external spur gears with gear wear. A geometric model for a new mesh relationship with gear wear is proposed, which is utilized to evaluate the influence of gear wear on mesh stiffness and unloaded static transmission error (USTE). Based on the mesh stiffness and USTE considering gear wear, a gear dynamic model is established, and the vibration characteristics of gear wear are numerically studied. Comparison with the experimental results verifies the proposed dynamic model based on the new mesh relationship. The numerical and experimental results indicate that gear wear does not change the structure of the spectrum, but it alters the amplitude of the meshing frequencies and their sidebands. Several condition indicators, such as root-mean-square, kurtosis, and first-order meshing frequency amplitude, can be regarded as important bases for judging gear wear state.

关键词: gear wear     mesh relationship     mesh stiffness     transmission error     vibration characteristics    

Chord error constraint based integrated control strategy for contour error compensation

Tie ZHANG, Caicheng WU, Yanbiao ZOU

《机械工程前沿(英文)》 2020年 第15卷 第4期   页码 645-658 doi: 10.1007/s11465-020-0601-7

摘要: As the traditional cross-coupling control method cannot meet the requirements for tracking accuracy and contour control accuracy in large curvature positions, an integrated control strategy of cross-coupling contour error compensation based on chord error constraint, which consists of a cross-coupling controller and an improved position error compensator, is proposed. To reduce the contour error, a PI-type cross-coupling controller is designed, with its stability being analyzed by using the contour error transfer function. Moreover, a feed rate regulator based on the chord error constraint is proposed, which performs speed planning with the maximum feed rate allowed by the large curvature position as the constraint condition, so as to meet the requirements of large curvature positions for the chord error. Besides, an improved position error compensation method is further presented by combining the feed rate regulator with the position error compensator, which improves the tracking accuracy via the advance compensation of tracking error. The biaxial experimental results of non-uniform rational B-splines curves indicate that the proposed integrated control strategy can significantly improve the tracking and contour control accuracy in biaxial contour following tasks.

关键词: cross-coupling controller     contour error     tracking error     position error compensator     feed rate regulator    

Kinematic error separation on five-axis NC machine tool based on telescoping double ball bar

Min WANG, Jianzhong HU, Tao ZAN

《机械工程前沿(英文)》 2010年 第5卷 第4期   页码 431-437 doi: 10.1007/s11465-010-0110-1

摘要: The theory and algorithm of the homogeneous transformation matrix (HTM) method are applied in establishing the kinematic error model of five-axis machining tool with two-axis turntable. Based on this model, a new method for the kinematic error separation in five-axis numerical control (NC) machining tool is proposed. In this study, three types of simultaneous three-axis control motions are designed for each rotary axis to identify the deviations. In the measurement, two translational axes and one rotary axis are simultaneously controlled to keep a constant distance between the tool and the worktable. Telescoping double ball bar is used to measure the relative distance between the spindle and the worktable in the motion of NC machining tool. Finally, the value measured by telescoping double ball bar is substituted into the model to obtain kinematic error of NC machining tool. Comparison has confirmed that the proposed method is high precision and can be applied to effectively and conveniently measure the five-axis machining tool.

关键词: error modeling     error separation     telescoping double ball bar     five-axis numerical control (NC) machining tool    

Robust ensemble of metamodels based on the hybrid error measure

《机械工程前沿(英文)》 2021年 第16卷 第3期   页码 623-634 doi: 10.1007/s11465-021-0641-7

摘要: Metamodels have been widely used as an alternative for expensive physical experiments or complex, time-consuming computational simulations to provide a fast but accurate analysis. However, challenge remains in the prior determination of the most suitable metamodel for a particular case because of the lack of information about the actual behavior of a system. In addition, existing studies on metamodels have largely restricted on solving deterministic problems (e.g., data from finite element models), whereas some real-life engineering problems (e.g., data from physical experiment) are stochastic problems with noisy data. In this work, a robust ensemble of metamodels (EMs) is proposed by combining three regression stand-alone metamodels in a weighted sum form. The weight factor is adaptively determined according to the hybrid error metric, which combines global and local error measures to improve the accuracy of the EMs. Furthermore, three typical individual metamodels that can filter noise are selected to construct the EMs to extend their application in practical engineering problems. Three well-known benchmark problems with different levels of noise and three engineering problems are used to verify the effectiveness of the proposed EMs. Results show that the proposed EMs have higher accuracy and robustness than the individual metamodels and other typical EMs in major cases.

关键词: metamodel     ensemble of metamodels     hybrid error measure     stochastic problem    

具有新概念的运动误差及形状误差的分离法——虚位数据法

洪迈生,李自军,苏恒,叶飞帆

《中国工程科学》 2002年 第4卷 第10期   页码 48-51

摘要:

提出了一种基于信号重建的虚位数据法,用此方法,可以按需要任意选择只分离形状误差或只分离运动误差,或者任意安排分离这两类误差的先后顺序,而不必变更传统的形状误差检测-分离系统,方式灵活,使用方便。

关键词: 虚位数据     信号重建     形状误差     运动误差     误差分离技术    

Choosing configurations of transmission line tower grounding by back flashover probability value

Dmitry KUKLIN

《能源前沿(英文)》 2016年 第10卷 第2期   页码 213-226 doi: 10.1007/s11708-016-0398-6

摘要: There is a considerable number of works devoted to electrical characteristics of grounding. These characteristics are important in general. However, in application to grounding of transmission line towers they are not enough to determine what grounding construction is preferable in some particular case, because these characteristics are calculated or measured apart from the grounded object, and only limited number of current (or voltage) source waveforms is used. This paper indicates reasons in favor of the fact that to choose the optimum design of grounding, the calculation model should include the tower as it is. The probability of back flashover, which provides both qualitative and quantitative estimate of the grounding structure efficiency, can be taken as the criterion for the grounding design. The insulation flashover probability is calculated on the basis of engineering method, which evaluates breakdown strength of insulation for nonstandard waveshapes, and probability data on lightning currents. Different approaches are examined for identifying the back flashover probability, as not only amplitudes but also other parameters can be taken into account. Finite-difference time-domain method is used for calculations of transients. It is found that lightning current waveform can greatly influence calculated back flashover probability value.

关键词: grounding     transmission line tower     back flashover probability     FDTD method    

Dependence of error sensitivity of frequency on bias voltage in force-balanced micro accelerometer

Lili CHEN, Wu ZHOU

《机械工程前沿(英文)》 2013年 第8卷 第2期   页码 146-149 doi: 10.1007/s11465-013-0260-z

摘要:

To predict more precisely the frequency of force-balanced micro accelerometer with different bias voltages, the effects of bias voltages on error sensitivity of frequency is studied. The resonance frequency of accelerometer under closed loop control is derived according to its operation principle, and its error sensitivity is derived and analyzed under over etching structure according to the characteristics of Deep Reaction Ion Etching (DRIE). Based on the theoretical results, micro accelerometer is fabricated and tested to study the influences of AC bias voltage and DC bias voltage on sensitivity, respectively. Experimental results indicate that the relative errors between test data and theory data are less than 7%, and the fluctuating value of error sensitivity under the range of voltage adjustment is less than 0.01 μm . It is concluded that the error sensitivity with designed parameters of structure, circuit and process error can be used to predict the frequency of accelerometer with no need to consider the influence of bias voltage.

关键词: Micro-Electro-Mechanical Systems (MEMS)     micro accelerometer     force-balanced micro accelerometer     frequency     error sensitivity    

A frequency error estimation for isogeometric analysis of Kirchhoff–Love cylindrical shells

《结构与土木工程前沿(英文)》 doi: 10.1007/s11709-023-0006-x

摘要: A frequency error estimation is presented for the isogeometric free vibration analysis of Kirchhoff–Love cylindrical shells using both quadratic and cubic basis functions. By analyzing the discrete isogeometric equations with the aid of harmonic wave assumption, the frequency error measures are rationally derived for the quadratic and cubic formulations for Kirchhoff–Love cylindrical shells. In particular, the governing relationship of the continuum frequency for Kirchhoff–Love cylindrical shells is naturally embedded into the frequency error measures without the need of explicit frequency expressions, which usually are not trivial for the shell problems. In accordance with these theoretical findings, the 2nd and 4th orders of frequency accuracy are attained for the isogeometric schemes using quadratic and cubic basis functions, respectively. Numerical results not only thoroughly verify the theoretical convergence rates of frequency solutions, but also manifest an excellent magnitude match between numerical and theoretical frequency errors for the isogeometric free vibration analysis of Kirchhoff–Love cylindrical shells.

关键词: isogeometric analysis     Kirchhoff–Love cylindrical shell     free vibration     frequency error     convergence    

Error measurement and assemble error correction of a 3D-step-gauge

MAO Xinyong, LI Bin, SHI Hanmin, LIU Hongqi, LI Xi, LI Peigen

《机械工程前沿(英文)》 2007年 第2卷 第4期   页码 388-393 doi: 10.1007/s11465-007-0067-x

摘要: A new artifact called 3D-step-gauge consisting of a pyramid array and a compound, is proposed to calculate geometrical errors for machine tools. Only one point on each profile of the pyramid in the array is probed, and its center coordinate can be calculated. Then, the intervals of the pyramids can be transfered a length standard to measure errors. Considering the differences in the structural parameters and the location of the pyramids, a volumetric error measurement method of discrete points is presented. Furthermore, the location errors between the calibration state and the measurement state are studied and their influences on the accuracy of the position measurement are investigated on an actual machine tool. The 3D-step-gauge was tested on an actual machine tool and the measurement result shows quick assembly, convenient measurement, and high accuracy.

关键词: volumetric     pyramid     assembly     accuracy     calibration    

Error analysis and optimization of a 3-degree of freedom translational Parallel Kinematic Machine

null

《机械工程前沿(英文)》 2014年 第9卷 第2期   页码 120-129 doi: 10.1007/s11465-014-0300-3

摘要:

In this paper, error modeling and analysis of a typical 3-degree of freedom translational Parallel Kinematic Machine is presented. This mechanism provides translational motion along the Cartesian X-, Y- and Z- axes. It consists of three limbs each having an arm and forearm with prismatic-revolute-revolute-revolute joints. The moving or tool platform maintains same orientation in the entire workspace due to its joint arrangement. From inverse kinematics, the joint angles for a given position of tool platform necessary for the error modeling and analysis are obtained. Error modeling is done based on the differentiation of the inverse kinematic equations. Variation of pose errors along XY and Z directions for a set of dimensions of the parallel kinematic machine is presented. A non-dimensional performance index, namely, global error transformation index is used to study the influence of dimensions and its corresponding global maximum pose error is reported. An attempt is made to find the optimal dimensions of the Parallel Kinematic Machine using Genetic Algorithms in MATLAB. The methodology presented and the results obtained are useful for predicting the performance capability of the Parallel Kinematic Machine under study.

关键词: translational Parallel Kinematic Machine     error modeling     global error transformation index    

Recent transmission of Mycobacterium tuberculosis in China: the implication of molecular epidemiology

null

《医学前沿(英文)》 2018年 第12卷 第1期   页码 76-83 doi: 10.1007/s11684-017-0609-5

摘要:

Tuberculosis (TB) has remained an ongoing concern in China. The national scale-up of the Directly Observed Treatment, Short Course (DOTS) program has accelerated the fight against TB in China. Nevertheless, many challenges still remain, including the spread of drug-resistant strains, high disease burden in rural areas, and enormous rural-to-urban migrations. Whether incident active TB represents recent transmission or endogenous reactivation has helped to prioritize the strategies for TB control. Evidence from molecular epidemiology studies has delineated the recent transmission of ( ) strains in many settings. However, the transmission patterns of TB in most areas of China are still not clear. Studies carried out to date could not capture the real burden of recent transmission of the disease in China because of the retrospective study design, incomplete sampling, and use of low-resolution genotyping methods. We reviewed the implementations of molecular epidemiology of TB in China, the estimated disease burden due to recent transmission of strains, the primary transmission of drug-resistant TB, and the evaluation of a feasible genotyping method of strains in circulation.

关键词: tuberculosis     recent transmission     molecular epidemiology     China    

Antibiotic resistome mostly relates to bacterial taxonomy along a suburban transmission chain

《环境科学与工程前沿(英文)》 2022年 第16卷 第3期 doi: 10.1007/s11783-021-1466-7

摘要:

• The α-diversities of resistome were lower in manure and compost than in soils.

关键词: Antibiotic resistance genes     Resistome     Bacterial taxonomy     Transmission chain    

Identification of thermal error in a feed system based on multi-class LS-SVM

Chao JIN, Bo WU, Youmin HU, Yao CHENG

《机械工程前沿(英文)》 2012年 第7卷 第1期   页码 47-54 doi: 10.1007/s11465-012-0307-6

摘要:

Research of thermal characteristics has been a key issue in the development of high-speed feed system. The thermal positioning error of a ball-screw is one of the most important objects to consider for high-accuracy and high-speed machine tools. The research work undertaken herein ultimately aims at the development of a comprehensive thermal error identification model with high accuracy and robust. Using multi-class least squares support vector machines (LS-SVM), the thermal positioning error of the feed system is identified with the variance and mean square value of the temperatures of supporting bearings and screw-nut as feature vector. A series of experiments were carried out on a self-made quasi high-speed feed system experimental bench HUST-FS-001 to verify the identification capacity of the presented method. The results show that the recommended model can be used to predict the thermal error of a feed system with good accuracy, which is better than the ordinary BP and RBF neural network. The work described in this paper lays a solid foundation of thermal error prediction and compensation in a feed system.

关键词: least squares support vector machine (LS-SVM)     feed system     thermal error     precision machining    

测量与信息技术

张国雄

《中国工程科学》 2000年 第2卷 第3期   页码 62-66

摘要:

测量是获取信息的重要手段。科学研究、生产、高科技发展都离不开测量。测量技术发展的重要特点是它与信息技术的融合,这是提高测量精度、在线和动态测量、复杂参数和复杂环境下测量、智能测量的需要。这一融合贯穿始终,它包括信号调制与解调、采样与重构、信号融合、数据压缩、滤波、信号变换、时间序列分析、谱分析、数据拟合与建模、模式识别、神经网络、仿真与虚拟、误差分离、误差补偿、冗余技术、决策与智能技术等,它们互相支持。文章通过三坐标测量机误差补偿、圆度和轴系误差测量,以及大型工程的柔性坐标测量系统,介绍其在提高测量精度、优化、自标定、丢失信息自恢复、系统重组等方面的作用及其关键技术。

关键词: 测量     信息技术     误差补偿     建模     冗余技术     误差分离    

标题 作者 时间 类型 操作

Planet position errors in planetary transmission: Effect on load sharing and transmission error

Miguel IGLESIAS, Alfonso FERNáNDEZ, Ana DE-JUAN, Ramón SANCIBRIáN, Pablo GARCíA

期刊论文

Mesh relationship modeling and dynamic characteristic analysis of external spur gears with gear wear

期刊论文

Chord error constraint based integrated control strategy for contour error compensation

Tie ZHANG, Caicheng WU, Yanbiao ZOU

期刊论文

Kinematic error separation on five-axis NC machine tool based on telescoping double ball bar

Min WANG, Jianzhong HU, Tao ZAN

期刊论文

Robust ensemble of metamodels based on the hybrid error measure

期刊论文

具有新概念的运动误差及形状误差的分离法——虚位数据法

洪迈生,李自军,苏恒,叶飞帆

期刊论文

Choosing configurations of transmission line tower grounding by back flashover probability value

Dmitry KUKLIN

期刊论文

Dependence of error sensitivity of frequency on bias voltage in force-balanced micro accelerometer

Lili CHEN, Wu ZHOU

期刊论文

A frequency error estimation for isogeometric analysis of Kirchhoff–Love cylindrical shells

期刊论文

Error measurement and assemble error correction of a 3D-step-gauge

MAO Xinyong, LI Bin, SHI Hanmin, LIU Hongqi, LI Xi, LI Peigen

期刊论文

Error analysis and optimization of a 3-degree of freedom translational Parallel Kinematic Machine

null

期刊论文

Recent transmission of Mycobacterium tuberculosis in China: the implication of molecular epidemiology

null

期刊论文

Antibiotic resistome mostly relates to bacterial taxonomy along a suburban transmission chain

期刊论文

Identification of thermal error in a feed system based on multi-class LS-SVM

Chao JIN, Bo WU, Youmin HU, Yao CHENG

期刊论文

测量与信息技术

张国雄

期刊论文