(2-RPU/RPS)&R混联机构的工作空间及其分拣应用

目的 针对包装生产线上需对食品、电子元器件等产品进行分拣的功能需求,提出一种新颖的(2-RPU/RPS)&R混联机构.方法 基于螺旋理论建立2-RPU/RPS并联机构的螺旋矩阵,并用修正的Kutzbach-Grübler公式对所得自由度数进行验证.通过机构的结构特征建立约束方程,并采用闭环矢量法求出机构的位置逆解.然后利用粒子群优化(PSO)算法分析机构的位置正解.最后采用数值搜索法求解机构的可达工作空间.结果 (2-RPU/RPS)&R混联机构具有4个自由度(3R1T).在PSO算法实例中,分析得到了动平台位置正解的数值解和适应度曲线,工作空间连续且无空洞,满足分拣活动范围的需求,在给出的应用实例中表明(2-RPU/RPS)&R混联机器人能很好地应用于手机包装生产线中物体的分拣和抓取等工作.结论 (2-RPU/RPS)&R混联机构运动学性能良好、工作空间大、运行平稳,适用于包装生产线上具有不同方位的物品的分拣功能需求.     

空间4R球面机构作为转动副的3RPS并联机构运动学分析

目的设计一种新型3RsPS并联机构,使得机构可以输出3个转动自由度与3个移动自由度耦合的运动。方法根据机构的几何关系,在4R空间机构连杆运动学分析的基础上,建立该机构的运动学方程,使用消元法对其运动学正、逆解进行了求解。使用空间4R机构替换3RPS并联机构的转动副,使得该机构在初始位形下的结构,与3RPS并联机构等效。结果使用Matlab计算得到了运动学方程消元后方程的最高次数,从而得到了运动学正解最多的个数。该机构具有3个自由度,3个移动输出和3个转动输出耦合,机构的运动学正解最多有16个,这与3RPS最多拥有的正解数目一致。结论得到了一种新型的3RsPS机构,该机构的特征为RS副的转动轴线是在空间变化的,该机构的输出为三维移动伴随三维转动,具有此类运动模式的并联机构在不规则形状的产品分拣筛选时,具有一定应用前景。     

照相明胶研究及应用的一些最新进展

本文介绍了1991年9月在英国剑桥大学召开的第六届RPS照相明胶国际会议上发表的部分论文。主要内容集中在制造、性质、增感相互作用、分析、坚膜及改性七个方面,它反映了近五年来照相明胶研究的最新进展和成就。     

美国PSA和英国RPS国际摄影

PSA和RPS国际影展是分别由美国摄影学会(The Photographic Society of America,简称PSA)和英国皇家摄影学会(The RoyalPhotographic Society,简称RPS)主办的国际影展.由于美国摄影学会、英国皇家摄影学会和国际摄影联盟(FIAP)并称当今世界三大摄影组织,因此,它们举办的影展也分外引人注目.     

第六届RPS照相明胶会议论文辑题录

1991年9月15～20日在英国剑桥大学召开了第六届RPS(英国皇家摄影协会)照相明胶会议,主要反映近几年照相照胶的发展动向及其研究成果,论文共计32篇,全文都刊登在《The Journal ofphotographic science》杂志1992年40卷5/6期(论文专辑)上,现将题目介绍如下:     

美国摄影学会、国际摄影联盟及其展览荣衔

美国摄影学会(PSA)、国际摄影联盟(FLAP)英国皇家摄影学会(RPS)并称世界三大著名摄影组织。在这三大摄影组织中，美国摄影学会和国际摄影联盟多年来一直致力于倡导国际摄影展览，对世界各地举办的国际摄影展览的规范、引导起着不可磨灭的作用。     

Neato新款扫地机器人推出支持RPS绘图定位

Neato XV Signature Pro配有激光测距系统，自带RPS绘图房间定位系统．在清扫之前感应生成所有房间的数字地图，规划直线路径进行清扫，以避免在清扫过程中撞到物体或者原地打转无法继续工作。更为重要的是可以自动探测和绘制通向其它房间的路径图；官方发布全新版本系统软件时，只需要将Neato XV SignaturePro连接至电脑即可进行软件升级。     

一种并联机构运动副摆放位置不同的静力学分析

目的运用螺旋理论在Matlab平台上对一种封装并联机构2-RPU/SPR,以及因其运动副摆放位置不同衍生出的3种两转一移并联机构2-UPR/SPR,2-UPR/RPS和2-RPU/RPS的静力学特性进行分析,并比较它们的优劣性。方法文中采用螺旋理论法对4种并联机构建立静力学数学模型,进而运用Matlab编程软件建立4个机构的程序模型,在Matlab中分2种情况对4个机构进行静力学分析。结果机构2-RPU/SPR的驱动力与其他3个机构相比相对较小;机构2-RPU/SPR的等效约束力和驱动力与其他3个机构相比变化波动较小。在动平台输出相同的情况下,机构2-RPU/SPR易于控制与驱动,灵活性高于其他3个机构;在动平台位姿相同的情况下,机构2-RPU/SPR抗外界干扰的能力优于其他3个机构。结论并联机构2-RPU/SPR比另外3个并联机构更好,在高精度包装工程中更具有实际应用前景。     

"白色证书"的研究及应用

一、"白色证书"的提出 近些年来,国际上出现了很多基于市场机制的、旨在促进能源可持续发展的政策工具.例如,欧洲的奥地利、比利时、丹麦、意大利等国家,实施了可再生能源配额制度(即"可再生能源配额标准",RPS)以及"绿色证书"交易机制.     

石墨烯的制备及其在超级电容器中的应用研究

石墨烯具有优异的物理、化学和力学性能，成为近年来的研究热点。尤其是其良好的导电性能和大的比表面积，使其在电化学领域中有着巨大的应用前景。综述了石墨烯的主要制备方法，重点介绍了石墨烯及其复合材料在超级电容器中的主要制备方法和应用研究，并对其未来的应用前景进行了展望。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.