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误差分析 3

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神经网络 2

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

三维形貌测量 1

不确定时延 1

中间钢塔 1

二维正交方阵码(2D-OOSC) 1

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光线跟踪;三角Bézier曲面;射线与曲面的交点;求根;混合裁剪 1

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Error compensation for tool-tip trace during cutting of laminated paper for rapid prototyping

Yucheng DING, Changhe LI, Dichen LI, Guoxin YU

《机械工程前沿(英文)》 2009年 第4卷 第2期   页码 111-119 doi: 10.1007/s11465-009-0020-2

摘要: Laminated object manufacturing (LOM) is one of the commercialized rapid prototyping (RP) processes, where a focused laser is usually used to cut the cross-section contours of a 3 D part and the grid hatchings of the part-exterior region on a sheet paper stack-wise. Using a laser beam as a cutter can be costly, and the thermal burning of a sheet paper along a laser scanning path can also cause an environment-polluting smoke. This paper presents a paper laminating RP system using a knife as the paper cutter instead of a laser beam. The knife holder is mounted through a radial bearing on the - positioning mechanism in such a way that the knife tip is eccentric to the bearing axis by a small distance (so-called offset). Therefore, the knife tip, which engages into the sheet paper during cutting, tends to follow the path of the -driven bearing axis by the error that depends on the path tangential and the eccentricity of the knife tip. A tractrix model is applied to describe the kinetic motion of the knife tip and a method is formulated to compensate for the tracing error of the eccentric knife tip by modifying the original cross-section contours of the part for each layer based on the tractrix equation. A study has also been performed regarding the effect of the knife tip geometry on the cutting notch of the sheet paper and on the roughness of the finished part.

关键词: rapid prototyping     laminated object manufacturing     knife-cutting     tracing error    

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    

Sensory innervation of the anterior eye segment in rats: a retrograde tracing study

Haixia LIU MD , Zhiwang LI MD , Min YANG MD , Xiang TIAN MS , Chaoying LI PhD , Lei PEI PhD ,

《医学前沿(英文)》 2009年 第3卷 第3期   页码 352-356 doi: 10.1007/s11684-009-0065-y

摘要: This study aimed to investigate the sensory innervation of the anterior eye segment in rats by retrograde tracing with 1,1-dioleyl-3,3,3,3-tetrameth-ylindocarbocyanine, 4-chlorobenesulfonate (FAST Dil) injected into the anterior chamber. In our study, the sensory innervation of distinct elements of the anterior segment of the rat’s eye, i.e. the cornea, ciliary body, iris, and trabecular meshwork, were studied by retrograde tracing using FAST Dil as a tracer. FAST Dil was injected into the anterior chambers of the rat’s eyes. The animals were sacrificed at different time points, i.e., 2, 3, 4, and 5 days after the injection. FAST Dil localization in trigeminal ganglions was studied with a fluorescent microscope. Two days after FAST Dil injection into the anterior chambers, the cornea, the ciliary body, the iris, and the trabecular meshwork were heavily labeled. Neurons in the ipsilateral trigeminal ganglion were also consistently labeled. The number of labeled cells increased over time until 4 days after FAST Dil injection. FAST Dil-labeled neurons could be divided into two parts. Most of the Dil-labeled neurons were concentrated in a sharp, longitudinal, spindle-like stripe, located in the dorso-medial side of the trigeminal ganglion, approximately two thirds of the dorsal portion. The other part of Dil-labeled neurons scattered laterally to the stripe, but just in one third of the dorsal region. Thus, with our preliminary results, we conclude that the primary afferent sensory neurons innervating the rat’s anterior eye segments aggregate in the dorso-medial part of the ipsilateral trigeminal ganglion. It is feasible to identify them using retrograde tracing with FAST Dil anterior chamber injection.

关键词: trigeminal ganglion     retrograde tracing    

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    

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    

Heat Integration retrofit analysis—an oil refinery case study by Retrofit Tracing Grid Diagram

Andreja NEMET, Jiří Jaromír KLEMEŠ, Petar Sabev VARBANOV, Valter MANTELLI

《化学科学与工程前沿(英文)》 2015年 第9卷 第2期   页码 163-182 doi: 10.1007/s11705-015-1520-8

摘要: Heat Integration has been established over the last decades as a proven chemical engineering methodology. Two design implementations are often used in the industry: grassroots and retrofit. Although various methods have been developed for retrofit, it still needs more development to ensure simultaneously thermodynamic feasibility and economic viability. In this paper, a novel graphical approach has been developed to facilitate the understanding of the current situation and scope of improvement. The Retrofit Tracing Grid Diagram presents all streams and heat exchangers in temperature scale and the heat exchangers are clearly separated from each other, enabling clear visualisation of the current state. The tool incorporates the previously developed Cross-Pinch Analysis as well as path approach for retrofit. Additionally, the non-vertical heat transfer can be evaluated. The application of the developed tool has been validated on an oil refinery case study. The applicability of the tool is evident as it can reveal additional options for modification that none of the previous methods considered.

关键词: Heat Integration     retrofit     Pinch Analysis     thermodynamic approach     oil refinery    

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    

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    

Tracing the impact of stack configuration on interface resistances in reverse electrodialysis by in situ

《环境科学与工程前沿(英文)》 2022年 第16卷 第4期 doi: 10.1007/s11783-021-1480-9

摘要:

• RED performance and stack resistance were studied by EIS and LSV.

关键词: Reverse electrodialysis     Electrochemical impedance spectroscopy     Concentration polarization     Spacer shadow effect    

Theoretical prediction and validation of global horizontal solar irradiance for a tropical climate in India

Sivasankari SUNDARAM,Jakka SARAT CHANDRA BABU

《能源前沿(英文)》 2015年 第9卷 第3期   页码 311-321 doi: 10.1007/s11708-015-0369-3

摘要: This paper aims to propose monthly models responsible for the theoretical evaluation of the global horizontal irradiance of a tropical region in India which is Sivagangai situated in Tamilnadu. The actual measured global horizontal irradiance hails from a 5 MW solar power plant station located at Sivagangai in Tamilnadu. The data were monitored from May 2011 to April 2013. The theoretical assessment was conducted differently by employing a programming platform called Microsoft Visual Basic 2010 Express. A graphical user interface was created using Visual Basic 2010 Express, which provided the evaluation of empirical parameters for model formulation such as daily sunshine duration ( ), maximum possible sunshine hour duration ( ), extra terrestrial horizontal global irradiance ( ) and extra terrestrial direct normal irradiance ( ). The proposed regression models were validated by the significance of statistical indicators such as mean bias error, root mean square error and mean percentage error from the predicted and the actual values for the region considered. Comparison was made between the proposed monthly models and the existing normalized models for global horizontal irradiance evaluation.

关键词: global horizontal irradiance (GHI)     mean bias error     root mean square error     mean percentage error     coefficient of regression     Visual Basic 2010 Express    

标题 作者 时间 类型 操作

Error compensation for tool-tip trace during cutting of laminated paper for rapid prototyping

Yucheng DING, Changhe LI, Dichen LI, Guoxin YU

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

Sensory innervation of the anterior eye segment in rats: a retrograde tracing study

Haixia LIU MD , Zhiwang LI MD , Min YANG MD , Xiang TIAN MS , Chaoying LI PhD , Lei PEI PhD ,

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

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

Lili CHEN, Wu ZHOU

期刊论文

Heat Integration retrofit analysis—an oil refinery case study by Retrofit Tracing Grid Diagram

Andreja NEMET, Jiří Jaromír KLEMEŠ, Petar Sabev VARBANOV, Valter MANTELLI

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

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

Tracing the impact of stack configuration on interface resistances in reverse electrodialysis by in situ

期刊论文

Theoretical prediction and validation of global horizontal solar irradiance for a tropical climate in India

Sivasankari SUNDARAM,Jakka SARAT CHANDRA BABU

期刊论文