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Optimal design of a linkage–cam mechanism-based redundantly actuated parallel manipulator

《机械工程前沿（英文）》 2021年第16卷第3期页码 451-467 doi: 10.1007/s11465-021-0634-6

摘要： A redundantly actuated parallel manipulator (RAPM) with mixed translational and rotational degrees of freedom (DOFs) is challenged for its dimensionally homogeneous Jacobian modeling and optimal design of architecture. In this paper, a means to achieve redundant actuation by adding kinematic constraints is introduced, which reduces the DOFs of the end-effector (EE). A generic dimensionally homogeneous Jacobian is developed for this type of RAPMs, which maps the generalized velocities of three points on the EE to the joint velocities. A new optimization algorithm derived from this dimensionally homogeneous Jacobian is proposed for the optimal design of this type of RAPMs. As an example, this paper presents a spatial RAPM involving linkages and cam mechanisms. This RAPM has 4 DOFs and 6 translational actuations. The linkage lengths and the position of the universal joints of the RAPM are optimized based on the dimensionally homogeneous Jacobian.

关键词： redundant actuation parallel manipulator linkage–cam mechanism Jacobian optimal design

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The linkage mechanism between urban intelligence and low carbon innovation

Ming LIN

《工程管理前沿（英文）》 2019年第6卷第4期页码 584-586 doi: 10.1007/s42524-019-0076-6

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Nonlinear dynamic behaviour of a cam mechanism with oscillating roller follower in presence of profile

Walha LASSAAD, Tounsi MOHAMED, Driss YASSINE, Chaari FAKHER, Fakhfakh TAHER, Haddar MOHAMED

《机械工程前沿（英文）》 2013年第8卷第2期页码 127-136 doi: 10.1007/s11465-013-0254-x

摘要：

In this paper we investigate the nonlinear dynamic behaviour of a cam mechanism with oscillating roller follower in presence of defects. The nonlinear developed lumped-mass model includes eight degrees of freedom with two nonlinear hertzian contacts. The first one is located between cam and first roller while the second is between second roller and the sliding rod. The nonlinear dynamic behaviour is described by second order differential equations which are resolved by using the implicit Newmark algorithm combined with the Newton-Raphson iterative scheme. The influence of the cam profile error on the dynamic behaviour is also investigated.

关键词： cam nonlinear behaviour oscillating roller follower profile error

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the improvement design of dynamic characteristics for the roller follower of a variable-speed plate cammechanism

Hui Ching FAN, Hong Sen YAN

《机械工程前沿（英文）》 2012年第7卷第1期页码 5-15 doi: 10.1007/s11465-012-0310-y

摘要：

Without modifying the cam contour, a cam mechanism with a variable input speed trajectory offers an alternative solution to flexibly achieve kinematic and dynamic characteristics, and then decrease the follower’s residual vibration. Firstly, the speed trajectory of cam is derived by employing Bezier curve, and motion continuity conditions are investigated. Then the motion characteristics between the plate cam and its roller follower are derived. To analyze the residual vibration, a single degree of freedom dynamic model of the elastic cam-follower system is introduced. Based on the motion equation derived from the dynamic model, the residual vibration of the follower is yielded. The design procedure to improve the kinematic and dynamic motion characteristics is presented and two design examples with discussions are provided. Finally, the simulations of the kinematic and dynamic models by ADAMS are carried out and verified that the design models as well as the performances of the mechanism are feasible.

关键词： cam mechanism variable input speed kinematic design dynamic design optimal design

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Selecting and prioritizing key factors for CAD/CAM software in small- and medium-sized enterprises using

Ghulam ZAKRIA, Zailin GUAN, Yasser RIAZ, Mirza JAHANZAIB, Anwar KHAN,

《机械工程前沿（英文）》 2010年第5卷第2期页码 157-164 doi: 10.1007/s11465-010-0017-x

摘要： In today’s fast-paced world, computer-aided design/computer-aided manufacturing (CAD/CAM) systems have become a necessary element in manufacturing industries. Prior to investment in a CAD/CAM system, it is essential for investor to know how to maximize their benefits from buying a new or by changing an existing CAD/CAM system. The purpose of this study is to provide a methodology to assist small- and medium-sized manufacturing companies of Pakistan in selecting a CAD/CAM system. It will also facilitate the software providers in recognizing the current state of affairs as well as preceding problems regarding the application of CAD/CAM in manufacturing firms when assisting them in choosing the direction for future development simultaneously. To accomplish this purpose, data have been collected about current CAD/CAM systems. Important criteria for system selection and parameters for evaluation have also been identified and prioritized. Analytic hierarchy process (AHP) is used as a decision-making technique for identifying and prioritizing important factors for CAD/CAM software selection. Expert Choice (AHP-based software) has been used to validate the results.

关键词： computer-aided design (CAD) computer-aided manufacturing(CAM) SMEs analytical hierarchal approach Expert Choice

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CAD/CAPP/CAM集成系统的研究与开发

魏而巍,梁木养,杨平

《中国工程科学》 2000年第2卷第4期页码 59-63

摘要：

文章介绍了可实用的CAD/CAPP/CAM集成系统。该系统是由机械产品设计人员，工艺人员和数控机床NC编程人员共同努力，在商品CAD/CAM软件Pro/ENGINEER平台上开发的。系统由三个子系统组成：零件信息识别子系统，CAPP子系统和自动CAM子系统。自动CAM子系统根据CAPP的结果，自动生成Pro/ENGINEER的NC工步，经过NC仿真后生成零件加工的刀位文件，再经过NC后处理生成NC代码。

关键词： CAD CAPP CAM 特征识别

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Nonlinear dynamics and analysis of a four-bar linkage with clearance

Yuanguang TANG, Zongyu CHANG, Xiaogang DONG, Yafei HU, Zhenjiang YU

《机械工程前沿（英文）》 2013年第8卷第2期页码 160-168 doi: 10.1007/s11465-013-0258-6

摘要：

In this paper, nonlinear dynamic behavior of a four-bar linkage considering clearance is studied. The dynamic model of the linkage with a clearance between coupler and rocker is developed firstly. Then the dynamic equations of this mechanism are solved by a numerical method. According to the calculated response, compliance, force and trajectory of pin in joint bearing are obtained. Effects of clearance magnitude and the relationship between a mechanism with clearance and without clearance are studied. By using Poincare Map, it is proved that strange attractors or chaos exist in the dynamic response. In addition, phenomena of chaos, periodic response and subharmonic response also can be found in the special condition. Bifurcation diagram is used to suggest that bifurcation and fractal phenomena exist in the dynamic response of this mechanism.

关键词： four-bar linkage chaos bifurcation strange attractors dynamics

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Principle and curve of planetary indexing cam mechanisms

LIU Ming-tao, ZHANG Ce, YANG Yu-hu

《机械工程前沿（英文）》 2006年第1卷第4期页码 475-478 doi: 10.1007/s11465-006-0063-6

摘要： A new type of planetary indexing cam mechanism called type !c is presented. The transmission principle of type !c is discussed. Based on the principle of formation of conjugate tooth contour, the equations of the cam s pitch curve are derived. The continuity and symmetry of the cam s pitch curve are also analyzed. It can be concluded that: 1) This type has no output institution so the output precision can be improved; 2) The asymmetrical two-ring structure is used to overcome dead point and its phase angle is equal to (π - 2π/n); 3) The continuous condition of the cam s pitch curve is that the average transmission ratio is -n in an intermittent motion period.

关键词： continuity planetary average transmission symmetry intermittent

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“医养智慧联动”的养老模式研究与探索

金心宇,夏琦,张唯,李兰娟

《中国工程科学》 2018年第20卷第2期页码 92-98 doi: 10.15302/J-SSCAE-2018.02.014

摘要：

我国已进入老龄化社会，而我国的养老建设事业仍处于不成熟阶段，养老问题已然成为我国亟待解决的重大问题之一。在国家相关政策的指引下，本文从我国国情出发，提出了一种以大型医院为诊疗主导，利用互联网实现与机构养老、社区养老和居家养老三种养老模式的有机连接，并融合老年病的人工智能云诊疗康复新技术的“医养智慧联动”养老模式。相关实践证明，利用互联网和人工智能及先进有效的综合诊疗技术来解决我国目前养老产业存在的问题具有重要的研究价值，也是一次非常有前景的尝试，符合国家的发展战略和相关政策。

关键词： “医养智慧联动” 智慧养老互联网人工智能辅助诊疗

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Influence of temperature on cam-tappet lubrication in an internal combustion engine

CHANG Qiuying, YANG Peiran, WANG Jing, CHEN Quanshi

《机械工程前沿（英文）》 2007年第2卷第4期页码 489-492 doi: 10.1007/s11465-007-0085-8

摘要： The transient thermo-elastohydrodynamic (TEHL) lubrication simulation and isothermal elastohydrodynamic (EHL) simulation were performed on the exhausting cam-tappet friction pair of an internal combustion engine. Although by employing the two models the center pressure, the thickness of the lubricant film and friction coefficient obtained were similar in the changing trend during a rotating cycle, the parameters make a great difference, especially for the thickness of the lubricant film; the TEHL was four times thicker than the EHL. These results show that the temperature should not be neglected in the study of the lubrication of cam-tappet pairs.

关键词： coefficient combustion isothermal elastohydrodynamic temperature thickness

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Shaking-moment balancing of mechanisms with principal vectors and momentum

V. van der WIJK

《机械工程前沿（英文）》 2013年第8卷第1期页码 10-16 doi: 10.1007/s11465-013-0359-2

摘要：

The design of shaking-moment-balanced linkages still is challenging. Considering moment balance in the very beginning of the design process of mechanisms is important for finding applicable solutions. For this purpose, the method of principal vectors is investigated, showing a compact notation of the angular momentum with respect to the center of mass. The moment balance conditions are derived for three elements in series from which balance solutions are synthesized and illustrated. From the application for moment balancing of a 4R four-bar linkage it is shown that the moment balancing of closed kinematic chains remains challenging.

关键词： shaking-moment balancing principal vector linkage angular momentum

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基于Watt连杆的可重复使用运载火箭腿式可展开着陆机构——原理、原型设计和实验验证 Article

于海涛, 田保林, 闫振, 高海波, 张宏剑, 吴会强, 王英超, 石玉红, 邓宗全

《工程（英文）》 2023年第20卷第1期页码 120-133 doi: 10.1016/j.eng.2022.05.015

摘要：

可重复使用运载火箭是降低太空运输成本的一种新途径。着陆机构是可重复使用运载火箭的重要组成部分，起到着陆支撑和吸收冲击的作用。本文提出了一种新型的可展开着陆机构（LDLM）。采用Watt-II型六杆机构，利用连杆变分法得到优选构型。本文建立了多目标优化范式，使得可展开着陆机构具有着陆支撑区域大、轻量化、连杆内力合理等优点，在此基础上，利用多目标遗传算法（NSGA-II）进化算法得到了可展开式着陆机构设计的最优尺寸参数。本文研制了全功能可重复使用运载火箭缩比样机，通过集成重力控制的展开方案促进展开动作，避免全范围驱动，采用双重锁紧机构提高展开状态时结构的可靠性，采用多级铝蜂窝缓冲器提供可靠的减震性能。实验结果表明，所提出的可展开式着陆机构能够提供快速平稳的展开（持续时间小于1.5 s），且对舱体的姿态扰动较小（偏航和俯仰波动小于6°）。此外，该机构在0.2 m自由落体测试中提供了足够的冲击衰减（加速度峰值小于10g）。所提出的可展开着陆机构可作为未来可重复使用运载火箭潜在的腿式起落架替代方案。

关键词：可重复使用运载火箭（RLV）可展开机构优化设计

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An intersection algorithm based on transformation

CHEN Xiao-xia, YONG Jun-hai, CHEN Yu-jian

《机械工程前沿（英文）》 2006年第1卷第3期页码 364-369 doi: 10.1007/s11465-006-0024-0

摘要： How to obtain intersection of curves and surfaces is a fundamental problem in many areas such as computer graphics, CAD/CAM, computer animation, and robotics. Especially, how to deal with singular cases, such as tangency or superposi

关键词： intersection superposi animation fundamental CAD/CAM

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Modality Municipal Public Transportation for Guangzhou—Group Rapid Transit System as Supplementary Linkage

Ru-jiang Zhao,Wung Hee Moh

《工程管理前沿（英文）》 2015年第2卷第4期页码 378-390 doi: 10.15302/J-FEM-2015061

摘要： As one of the primary business centers of China, Guangzhou has been undergoing rapid growth and expansion. Over the past decade, the Guangzhou Municipality Government has significantly upgraded its transport infrastructure, especially with the highly beneficial expansion of its Subway Mass Rapid Transit (MRT) system. Positive steps have also been taken to continue planning the construction of new roads, a Bus Rapid Transit (BRT) system and other transportation facilities. Further administrative and regulatory measures have also been implemented to control the situation, such as the banning of motorcycles from the central city area and the limitation of new automobile registrations. However, Guangzhou continues to face serious challenges of traffic congestion in and around the city center owing to further intensification of its population with economic growth. The need to ease Guangzhou’s stretched public transportation resources, and at the same time to support the realization of its “Eastward Advance” strategy, presents a unique challenge and opportunity to develop an advanced high-efficiency public transportation modality for Guangzhou, viz. the Group Rapid Transit (GRT) involving the use of automation-guided (driverless) smart-vehicles. This paper outlines the PRT/GRT (PRT: Personal Rapid Transit) smart-vehicle modality and also puts forth a proposal of Guangzhou’s first GRT route as the city’s first dedicated transportation link to the scenic landscape of the Eastern Tourism Zone. This GRT route will help in diffusing the city’s traffic congestion as well as support the effectuation of Guangzhou’s “Eastern Expansion” strategy, supplementing the ongoing expansion of the Guangzhou Municipality’s subway MRT networks.

关键词： public transportation system innovative city transportation Subway Mass Rapid Transit (MRT) Bus Rapid Transit (BRT) Group Rapid Transit (GRT) Personal Rapid Transit (PRT)

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Statistical considerations for genomic selection

Huimin KANG, Lei ZHOU, Jianfeng LIU

《农业科学与工程前沿（英文）》 2017年第4卷第3期页码 268-278 doi: 10.15302/J-FASE-2017164

摘要： Genomic selection is becoming increasingly important in animal and plant breeding, and is attracting greater attention for human disease risk prediction. This review covers the most commonly used statistical methods and some extensions of them, i.e., ridge regression and genomic best linear unbiased prediction, Bayesian alphabet, and least absolute shrinkage and selection operator. Then it discusses the measurement of the performance of genomic selection and factors affecting the prediction of performance. Among the measurements of prediction performance, the most important and commonly used measurement is prediction accuracy. In simulation studies where true breeding values are available, accuracy of genomic estimated breeding value can be calculated directly. In real or industrial data studies, either training-testing approach or -fold cross-validation is commonly employed to validate methods. Factors influencing the accuracy of genomic selection include linkage disequilibrium between markers and quantitative trait loci, genetic architecture of the trait, and size and composition of the training population. Genomic selection has been implemented in the breeding programs of dairy cattle, beef cattle, pigs and poultry. Genomic selection in other species has also been intensively researched, and is likely to be implemented in the near future.

关键词： genomic estimated breeding value genomic selection linkage disequilibrium statistical methods