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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    

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    

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    

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    

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    

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

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    

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    

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    

过程强化装置中双偏心转子的运动分析

朱瑞林,朱国林

《中国工程科学》 2012年 第14卷 第10期   页码 90-96

摘要:

当偏心转子绕定轴旋转时,实际上只有其几何圆心作简谐振动(正/余弦运动),某些情况下由转子驱动的构件(如活塞)并不能作同样的简谐振动,因此在一些过程设备上应用双偏心转子时,会引起一些相关问题,如压力变化问题。为此,在分析一种过程强化装置中所采用的双偏心转子的运动规律的基础上,发现了由于偏心转子所驱动的两活塞的运动不完全对称,可能引起设备内介质压力变化的原因,并提出了相应的解决措施。

关键词: 转子     活塞     简谐振动    

Evaluation of the stability of terraced slopes in clayey gravel soil using a novel numerical technique

《结构与土木工程前沿(英文)》 2023年 第17卷 第5期   页码 796-811 doi: 10.1007/s11709-023-0922-9

摘要: Conventional geotechnical software limits the use of the strength reduction method (SRM) based on the Mohr–Coulomb failure criterion to analyze the slope safety factor (SF). The use of this constitutive model is impractical for predicting the behavior of all soil types. In the present study, an innovative numerical technique based on SRM was developed to determine SF using the finite element method and considering the extended Cam–clay constitutive model for clayey gravel soil as opposed to the Mohr–Coulomb model. In this regard, a novel user subroutine code was employed in ABAQUS to reduce the stabilizing forces to determine the failure surfaces and resist and drive shear stresses on a slope. After validating the proposed technique, it was employed to investigate the performance of terraced slopes in the context of a case study. The impacts of geometric parameters and different water table elevations on the SF were examined. The results indicated that an increase in the upper and lower slope heights led to a decrease in SF, and a slight increase in the horizontal offset led to an increase in the SF. Moreover, when the water table elevation was lower than the toe of the terraced slope, the SF increased because of the increase in the uplift force as a resistant component.

关键词: terraced slope     safety factor     finite element method     ABAQUS     extended Cam–clay    

CNC programming system for complex components based on KBE within integrated environment of CAD/CAPP/CAM

Shengwen ZHANG, Guicheng WANG, Liang ZHANG, Xifeng FANG

《机械工程前沿(英文)》 2009年 第4卷 第1期   页码 97-102 doi: 10.1007/s11465-009-0007-z

摘要: To promote the research and development of modern digital and intelligent manufacturing technology and overcome shortcomings of computerized numerical control(CNC) programming for complex components, an innovative idea has been proposed to introduce knowledge based engineering (KBE) into the field of CNC programming within the integrated environment of CAD/CAPP/CAM. This paper constructs the architecture of CNC programming based on KBE within CAD/CAPP/CAM and explores the key technology of applying KBE to CNC programming — knowledge representation, knowledge acquisition, knowledge reasoning, and generalized knowledge base system of CNC programming. The integration of the CAD/CAM system and the CAPP system of enterprises has been achieved by taking the powerful CAD/CAM system of UG NX as a platform. The prototype system of CNC programming for complex components based on KBE within CAD/CAPP/CAM has been developed by means of UG/Open,VC++6.0, and SQL Sever 2000. Finally, a frame example, one of the complex components of a marine diesel, is presented, and the academic production and the intelligence of the system are verified.

关键词: NC programming     CAD/CAPP/CAM     KBE    

标题 作者 时间 类型 操作

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

期刊论文

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

期刊论文

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,

期刊论文

CAD/CAPP/CAM集成系统的研究与开发

魏而巍,梁木养,杨平

期刊论文

Principle and curve of planetary indexing cam mechanisms

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

期刊论文

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

Hui Ching FAN, Hong Sen YAN

期刊论文

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

CHANG Qiuying, YANG Peiran, WANG Jing, CHEN Quanshi

期刊论文

An intersection algorithm based on transformation

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

期刊论文

过程强化装置中双偏心转子的运动分析

朱瑞林,朱国林

期刊论文

Evaluation of the stability of terraced slopes in clayey gravel soil using a novel numerical technique

期刊论文

CNC programming system for complex components based on KBE within integrated environment of CAD/CAPP/CAM

Shengwen ZHANG, Guicheng WANG, Liang ZHANG, Xifeng FANG

期刊论文