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Task-space position/attitude tracking control of FAST fine tuning system

QI Lin, ZHANG Hui, DUAN Guanghong

《机械工程前沿（英文）》 2008年第3卷第4期页码 392-399 doi: 10.1007/s11465-008-0056-8

摘要： This paper addresses the task-space position/attitude tracking control of a suspended parallel robot, which is being developed in the framework of a five-hundred meter aperture spherical radio telescope (FAST) project. Based on the quaternion algebra, a novel model-independent task-space PD controller that ensures end-effector position and attitude tracking is presented. The simulation and experimental results show that the new controller has better control effects than the traditional joint-space controller.

关键词： telescope five-hundred end-effector controller simulation

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Drive system design and error analysis of the 6 degrees of freedom segment erector of shield tunneling machine

Hu SHI, Guofang GONG, Huayong YANG

《机械工程前沿（英文）》 2011年第6卷第3期页码 369-376 doi: 10.1007/s11465-011-0223-1

摘要：

Focusing on a segment erector of a shield-tunneling machine developed with 6 degrees of freedom (DOF) and controlled by electro-hydraulic proportional systems, the kinematics of the segment erection process is presented. The perturbation method in the error analysis is introduced to establish the position and attitude error model, considering a number of factors such as the hydraulic drive, control accuracy, and tolerance in manufacturing and assembly. Dynamic simulations are carried out to obtain the controlling precision of electrohydraulic drive systems. Formulas for calculating the position and attitude error of the grip hand of the segment erector are derived. The calculation results verify the practicality and effectiveness of the error analysis, providing a foundation for practical designing, manufacturing, and assembling of the segment of the erecting mechanism.

关键词： shield tunneling machine segment erector kinematics position and attitude precision

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Air-bearing position optimization based on dynamic characteristics of ultra-precision linear stages

CHEN Xuedong, LI Zhixin

《机械工程前沿（英文）》 2008年第3卷第4期页码 400-407 doi: 10.1007/s11465-008-0060-z

摘要： Air-bearings are installed between the stator and the mover of ultra-precision linear stages to suppress vibration and mechanical contact. Spring-damping elements are used to emulate the complex interaction of the finite element model (FEM) developed in this paper and the system dynamic behaviors are analyzed. Through the experimental modal test, the validity and reliability of the model are proven. However, the dynamic characteristics including mode frequency, mode shape, and response amplitude are obviously changed with the position of air-bearings. The combined optimization method is used to optimize the air-bearings position. The best and worst positions are obtained using the dynamic characteristic analysis. The method can be generalized to the connection position of different components in manufacture elements and to implement the system dynamic characteristics optimization when the connection position can be changed.

关键词： manufacture different interaction air-bearings response amplitude

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Electrorheological damper for the ultra-precision air bearing stage

ZHU Yu, JIA Songtao, CHEN Yaying, LI Guang

《机械工程前沿（英文）》 2008年第3卷第2期页码 158-163 doi: 10.1007/s11465-008-0031-4

摘要： This paper illustrates how the electrorheological damper substantially improves the performance of the ultra-precision air bearing stage. Smart materials such as electrorheological fluids have attracted many researchers’ attention because of their resistance changeable performance in different electric fields. Meanwhile, the ultra-precision air bearing stage driven by the linear-motor is characterized by zero mechanical damping and poor anti-disturbance. To solve this problem and consider the characteristics of electrorheological fluids, an electrorheological damper is proposed in this paper. The electrorheological damper’s characteristics in high electric fields are obtained based on the Eyring constitutive model, which smoothly transits from the pre-yield to post-yield region. To enhance the performance of the electrorheological damper, which takes effect only when the stage is going to decelerate or position, the on-off and sliding mode control methods design and optimize the controller. The results prove that by using the advanced sliding mode control method, the characteristics of the ultra-precision air bearing stage can be effectively improved through the introduction of the electrorheological damper.

关键词： post-yield linear-motor advanced sliding pre-yield position

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Precision control system of two-DOF stage with linear ultrasonic motor

ZHANG Hanlei, SHI Yunlai, ZHAO Chunsheng

《机械工程前沿（英文）》 2008年第3卷第4期页码 421-425 doi: 10.1007/s11465-008-0063-9

摘要： Using an appropriate control method, linear ultrasonic motors can be used in applications requiring high position accuracy. In this paper, a closed loop PI control system is designed to achieve high position accuracy during the control of a two-DOF stage driven by linear ultrasonic motors. Two ultrasonic motors are mounted on the stage to generate motion in two orthogonal directions. The PI control algorithm is used to increase the stability and accuracy of position control. The -axis mover covers 30 mm forward and backward in less than 0.3 s settling time and the -axis mover in less than 0.4 s. Experimental results denote that the control strategy proposed in this paper appears to have high efficiency, quick response, and high accuracy.

关键词： settling position accuracy PI control control algorithm orthogonal

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Experimental and CFD analysis of nozzle position of subsonic ejector

Xilai ZHANG, Shiping JIN, Suyi HUANG, Guoqing TIAN

《能源前沿（英文）》 2009年第3卷第2期页码 167-174 doi: 10.1007/s11708-009-0001-5

摘要： The influence of nozzle position on the performance of an ejector was analyzed qualitatively with free jet flow model. Experimental investigations and computational fluid dynamics (CFD) analysis of the nozzle position of the subsonic ejector were also conducted. The results show that there is an optimum nozzle position for the ejector. The ejecting coefficient reaches its maximum when the nozzle is positioned at the optimum and decreases when deviating. Moreover, the nozzle position of an ejector is not a fixed value, but is influenced greatly by the flow parameters. Considering the complexity of the ejector, CFD is reckoned as a useful tool in the design of ejectors.

关键词： ejector nozzle position ejecting coefficient CFD

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Robust energy-efficient train speed profile optimization in a scenario-based position–time–speed network

《工程管理前沿（英文）》 2021年第8卷第4期页码 595-614 doi: 10.1007/s42524-021-0173-1

摘要： Train speed profile optimization is an efficient approach to reducing energy consumption in urban rail transit systems. Different from most existing studies that assume deterministic parameters as model inputs, this paper proposes a robust energy-efficient train speed profile optimization approach by considering the uncertainty of train modeling parameters. Specifically, we first construct a scenario-based position–time–speed (PTS) network by considering resistance parameters as discrete scenario-based random variables. Then, a percentile reliability model is proposed to generate a robust train speed profile, by which the scenario-based energy consumption is less than the model objective value at

α

confidence level. To solve the model efficiently, we present several algorithms to eliminate the infeasible nodes and arcs in the PTS network and propose a model reformulation strategy to transform the original model into an equivalent linear programming model. Lastly, on the basis of our field test data collected in Beijing metro Yizhuang line, a series of experiments are conducted to verify the effectiveness of the model and analyze the influences of parameter uncertainties on the generated train speed profile.

关键词： robust train speed profile percentile reliability model scenario-based position–time–speed network mixed-integer programming

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优化光学亚像素定位精度极限——揭示小PSF的像素相位效应 Article

战海洋, 邢飞, 宝竞宇, 孙婷, 陈真真, 尤政, 袁利

《工程（英文）》 2023年第27卷第8期页码 140-149 doi: 10.1016/j.eng.2023.03.009

摘要：

Subpixel localization techniques for estimating the positions of point-like images captured by pixelated image sensors have been widely used in diverse optical measurement fields. With unavoidable imaging noise, there is a precision limit when estimating the target positions on image sensors, which depends on the detected photon count, noise, point spread function (PSF) radius, and PSF’s intra-pixel position. Previous studies have clearly reported the effects of the first three parameters on the precision limit but have neglected the intra-pixel position information. Here, we develop a localization precision limit analysis framework for revealing the effect of the intra-pixel position of small PSFs. To accurately estimate the precision limit in practical applications, we provide effective PSF (ePSF) modeling approaches and apply the Cramér-Rao lower bound. Based on the characteristics of small PSFs, we first derive simplified equations for finding the best precision limit and the best intra-pixel region for an arbitrary small PSF; we then verify these equations on real PSFs. Next, we use the typical Gaussian PSF to perform a further analysis and find that the final optimum of the precision limit is achieved at the pixel boundaries when the Gaussian radius is as small as possible, indicating that the optimum is ultimately limited by light diffraction. Finally, we apply the maximum likelihood method. Its combination with ePSF modeling allows us to successfully reach the precision limit in experiments, making the above theoretical analysis effective. This work provides a new perspective on combining image sensor position control with PSF engineering to make full use of information theory, thereby paving the way for thoroughly understanding and achieving the final optimum of the precision limit in optical localization.

关键词： Optical measurement Subpixel localization Precision limit optimization Small point spread functions Centroiding Star sensors

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Strategic position and development prospects of nuclear energy in China

SHEN Wenquan

《能源前沿（英文）》 2007年第1卷第2期页码 125-128 doi: 10.1007/s11708-007-0015-9

摘要： By analyzing the challenges of China s energy supply, an excellent perspective of nuclear power development in the country has been described. Taking into account the near-, mid-, and long-term development requirements, a comprehensive, coordinated and sustainable nuclear power program is proposed. Thus, our national nuclear industry can not only catch up with the world s advanced level in proper time, but also possess enough stamina for sustainability.

关键词： development excellent perspective long-term development comprehensive national

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Do not let precision medicine be kidnapped

null

《医学前沿（英文）》 2015年第9卷第4期页码 512-513 doi: 10.1007/s11684-015-0425-8

摘要：

Obama’s precision medicine initiative made the medical community boil over after the initiative’s release. Precision medicine has been advocated by the majority of scientists and doctors. However, some experts have questioned this concept. This article does not oppose precision medicine. However, the incentive of vigorously promoting precision medicine at present is a concern.

关键词： precision medicine personalized medicine genomics

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Review on the progress of ultra-precision machining technologies

Julong YUAN, Binghai LYU, Wei HANG, Qianfa DENG

《机械工程前沿（英文）》 2017年第12卷第2期页码 158-180 doi: 10.1007/s11465-017-0455-9

摘要：

Ultra-precision machining technologies are the essential methods, to obtain the highest form accuracy and surface quality. As more research findings are published, such technologies now involve complicated systems engineering and been widely used in the production of components in various aerospace, national defense, optics, mechanics, electronics, and other high-tech applications. The conception, applications and history of ultra-precision machining are introduced in this article, and the developments of ultra-precision machining technologies, especially ultra-precision grinding, ultra-precision cutting and polishing are also reviewed. The current state and problems of this field in China are analyzed. Finally, the development trends of this field and the coping strategies employed in China to keep up with the trends are discussed.

关键词： ultra-precision grinding ultra-precision cutting ultra-precision polishing research status in China development tendency

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Trajectory planning and base attitude restoration of dual-arm free-floating space robot by enhanced bidirectional

Zongwu XIE1 , Xiaoyu ZHAO1 , Zainan JIANG1 , Haitao YANG2 , Chongyang LI1

《机械工程前沿（英文）》 2022年第17卷第1期 doi: 10.1007/s11465-021-0658-y

摘要： When free-floating space robots perform space tasks, the satellite base attitude is disturbed by the dynamic coupling. The disturbance of the base orientation may affect the communication between the space robot and the control center on earth. In this paper, the enhanced bidirectional approach is proposed to plan the manipulator trajectory and eliminate the final base attitude variation. A novel acceleration level state equation for the nonholonomic problem is proposed, and a new intermediate variable-based Lyapunov function is derived and solved for smooth joint trajectory and restorable base trajectories. In the method, the state equation is first proposed for dual-arm robots with and without end constraints, and the system stability is analyzed to obtain the system input. The input modification further increases the system stability and simplifies the calculation complexity. Simulations are carried out in the end, and the proposed method is validated in minimizing final base attitude change and trajectory smoothness. Moreover, the minute internal force during the coordinated operation and the considerable computing efficiency increases the feasibility of the method during space tasks.

关键词： free-floating space robot dual arm coordinated operation base attitude restoration bidirectional approach

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Self-generation of machining precision and its realization in lapping of super precision solid balls

ZHANG Bopeng

《机械工程前沿（英文）》 2008年第3卷第3期页码 348-353 doi: 10.1007/s11465-008-0065-7

摘要： This paper presents the principle of self-generation of machining precision by explaining its basic concept and five necessary conditions for forming a system with self-organization capability. A self-generation system is a kind of system with self-organization capability. The self-generation of machining precision for solid balls with super precision is emphatically explained. From the viewpoint of self-organization, there are three types of systems including system 1 with the self-regulation capability, 2 with the self-determination capability of goals, and 3 with the self-organization capability. Although they are all closed loop control systems, they have different constructions and functions. Necessary conditions for achieving self-generation of machining precision are given. Establishment of the system for machining solid balls with super precision is discussed. Self-generation of machining precision for solid balls with super precision on the basis of the capability of self-removal of errors is presented. Self-generation includes the ability of self-removal of errors for solid balls, convergence of self-removal of errors, self-generation of precision, and self-generating system for the given.

关键词： self-generation necessary self-regulation capability viewpoint Necessary

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Human pangenome: far-reaching implications in precision medicine

《医学前沿（英文）》 doi: 10.1007/s11684-023-1039-1

摘要： Human pangenome: far-reaching implications in precision medicine

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燃油喷雾形态主动控制的可能性 Review

Masataka Arai

《工程（英文）》 2019年第5卷第3期页码 519-534 doi: 10.1016/j.eng.2019.04.010

摘要：

内燃机（ICE）对于汽车是有吸引力的动力源，具有良好的可储存性、可运输性，同时需要供应高能量密度的液体燃料。具有高性能和低环境危害的紧凑型内燃机是内燃机发展趋势。未来必须把燃油喷雾智能主动控制的燃烧作为解决传统内燃机相关重大问题（如排放）的突破性技术。已发展出在喷雾期间形成预期的燃料喷射速率和喷射模式的技术，并且传统内燃机可以在一定程度上控制燃烧。但是在燃烧范围内，燃料在空间上的扩散并未取得预期进展。因此，对于燃烧的智能控制，新且有效的燃油喷雾主动控制技术是非常必要的。空化、闪蒸、喷雾- 喷雾相互作用、喷雾-壁面相互作用和空气流动是有可能实现燃油喷雾形态主动控制的基础。本文使用文献中的论据来讨论未来喷雾燃烧的智能紧凑内燃机中喷雾形态主动控制技术的可能性。

关键词：内燃机，燃料喷雾，喷雾控制，喷雾形态，喷油器

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标题作者时间类型操作

Task-space position/attitude tracking control of FAST fine tuning system

QI Lin, ZHANG Hui, DUAN Guanghong

期刊论文

Drive system design and error analysis of the 6 degrees of freedom segment erector of shield tunneling machine

Hu SHI, Guofang GONG, Huayong YANG

期刊论文

Air-bearing position optimization based on dynamic characteristics of ultra-precision linear stages

CHEN Xuedong, LI Zhixin

期刊论文