基于旋量理论的STANFORD机器人的逆运动学分析

针对Stanford机器人关节的结构特点,基于旋量理论,采用Paden-Kahan子问题的方法求解Stanford机器人的运动反解。研究表明:该方法可消除多关节耦合变量,大大简化计算量,计算精度高,为求解Stanford机器人的运动学逆解提供了一种新方法。     

管内锚固式相贯线专用焊接机器人

管道插接相贯线焊缝是典型的、复杂的空问焊缝.针对管道插接焊缝的特殊焊接工艺要求,采用串并联混合方式设计了一种新型的5自由度焊接机器人.机器人以管道内壁为锚固对象,实现了机器人锚固、运动机构、焊枪姿态调节机构和送丝机构的一体化设计.机器人利用3个关节对焊枪位置进行控制,利用2自由度的自动定心手腕机构对焊枪进行姿态控制,实现了焊枪位置和焊枪姿态的独立控制.针对该专用焊接机器人,建立了焊接机器人的运动学模型,给出了机器人运动学模型解法.实际焊接试验表明,该焊接机器人锚固牢固、定位准确,焊接过程可控性好,控制模型能够满足空间相贯线焊缝的焊接工艺要求.     

六自由度医用摆位机器人机构设计与研究

针对固定束重离子治疗室精确放疗需求,设计了一种六自由度医用摆位机器人,提出其机构设计方案,并建立虚拟样机模型。避免利用传统Denavit-Hartenberg(D-H)参数法对机器人进行运动学建模时的缺陷,引入了一种基于李群刚体运动特殊欧式群和旋量理论构建摆位机器人运动学模型的方法;基于所建立的运动学模型,对医用摆位机器人机构件碰撞干涉、工作空间、束流辐照范围进行仿真研究。结果表明:所设计的六自由度医用摆位机器人能满足在连续空间内精确运动和定位的条件,且能很好地满足较大范围内多方向束流辐照的需求。     

二自由度仿生手指形焊枪结构设计及仿真

目前,传统的焊接机器人在实现空间复杂曲线的焊接和全位置焊接的过程中,需要机器人的个个关节进行耦合调节,机器人系统惯量增大,且容易引起干涉现象。基于降低机器人系统惯量,增强系统刚度,简化控制,避免干涉,实现焊枪的时时调节功能。以相贯线焊接为例,创新性地提出了一种能够自身调节工作角和行走角功能的二自由度仿手指形焊枪,建立D-H坐标系对仿生手指形焊枪进行了运动学分析;通过运动学仿真,未检查出系统干涉和碰撞,工作角和行走角调节机构的调节范围能够达到焊接工艺要求,从而验证了机构设计的合理性,为实现精确焊接提供了基础。     

一种平面二自由度并联机器人承载能力分析

以一种可实现末端运动平台平动且具有较小运动惯量的平面二自由度并联机器人机构为研究对象,分析其承载能力性能。与传统的分析和优化设计方法不同,综合考虑机器人机构的几何尺寸和运动变量的变化范围,作为机器人机构的运动学参数,利用空间模型理论,建立了机器人机构的设计空间。在设计空间内计算机器人机构的承载能力性能指标并绘制了相应的承载能力性能图谱,并探讨了机构承载能力性能指标与运动学参数之间的关系。这些图谱为设计者评价该机器人机构的承载能力性能和选择优化的运动学参数提供了帮助。提出的新方法也为以移动副为驱动的平面并联机器人分析与优化设计提供了一种有效的新途径。     

基于螺旋理论的6R串联工业机器人奇异位形分析

针对6自由度串联工业机器人,对其工作空间中的奇异位形进行了分析。基于旋量理论,运用旋量指数积(POE)方法对机器人进行运动学建模,得到正运动学方程,并基于旋量指数积法对速度雅克比矩阵进行了推导。根据机器人处于奇异位形时的条件,对雅克比矩阵的行列式进行求解,从而得到机器人处于奇异位形时的所有情况,并给出了发生奇异时的机器人的构型。在此基础上,基于可操作度、雅克比条件数及最小奇异值等灵巧度指标使用MATLAB对机器人的奇异位形进行了仿真,仿真结果表明该机器人在3种情况下处于奇异位形,与分析结果一致,验证了文中方法的正确性。     

一种平面二自由度并联机器人承载能力分析（英文）

以一种可实现末端运动平台平动且具有较小运动惯量的平面二自由度并联机器人机构为研究对象,分析其承载能力性能。与传统的分析和优化设计方法不同,综合考虑机器人机构的几何尺寸和运动变量的变化范围,作为机器人机构的运动学参数,利用空间模型理论,建立了机器人机构的设计空间。在设计空间内计算机器人机构的承载能力性能指标并绘制了相应的承载能力性能图谱,并探讨了机构承载能力性能指标与运动学参数之间的关系。这些图谱为设计者评价该机器人机构的承载能力性能和选择优化的运动学参数提供了帮助。提出的新方法也为以移动副为驱动的平面并联机器人分析与优化设计提供了一种有效的新途径。     

基于旋量理论的4-R(SS)2并联机器人正运动学分析

研究机器人运动学较为传统的方法为D-H参数法,以4-R(SS)2并联机器人为研究对象,基于旋量理论,根据指数积公式对该机器人进行正运动学分析,得到机器人的位姿变换矩阵。旋量法只需要建立惯性坐标系S和工具坐标系T,经过每一个关节变量之间的变换,最终可得到其运动学方程。与D-H参数法相比,此方法使运动学模型变得更为简单,并且具有更明确的几何意义。最后对并联机器人进行运动仿真,构建其仿真模型,确定机器人各结构的参数,输入随机关节变量,得到的结果与文中计算的结果进行对比,验证本文方法的准确性。     

一种串联机器人的实时运动仿真

提出一种基于六维计算机输入设备的机器人实时运动仿真方法.六维计算机输入设备采用并联机构原理,将操作块通过六条支链和底座连接,通过探测各个支链上行程开关的开合分布情况,能够准确的判断操作块的三维平移运动和三维旋转运动.给出了将SolidWorks模型导入到VisualC++环境的步骤,以及采用六维计算机输入设备进行实时控制的具体方法.最后分析了一种串联机器人的运动学模型并基于此给出了实时控制的仿真实例.     

仿生六足机器人机构设计与运动分析

基于蜜蜂腿部结构及运动步态特点和仿生设计基本原理,设计了一种新型六足机器人机构,可实现不同运动步态下的前进、后退和转向,具有较高的步态稳定性和环境适应性。运用空间分解法构建了机器人单腿的运动学模型,利用消元法对模型进行求解,得到逆运动学的唯一解。通过数值求解获得了六足机器人足部末端的运动轨迹,验证了运动学模型的正确性。借鉴蜜蜂的运动步态特征,规划了六足机器人直行和转弯时的运动步态。该研究为六足机器人机构设计与步态规划提供了新的思路和理论参考。     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

INTRODUCTION TO PATENTS

The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less.     

China Foundry Week 2014

China Foundry Week, hosted by the Foundry Institution of Chinese Mechanical Engineering Society （FICMES） each year, is a large academic event in China. It is one of the ten high-impact activities sponsored by the Chinese Mechanical Engineering Society.     

17th Conference of Hydrodynamic and Electromechanical Control Engineering Call for papers

正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.     

Formulas of Tension of Continuous Rolling Process

The development of computer controlled continuous rolling process calls for a mathematical expression that can express the inequality condition of "constant flow". Tension is the link of the continuous rolling process. From the condition of dynamic equilibrium, a differential equation of tension is given out. On the basis of the physical rules established from the industrial practice and experimental studies, the law of volume constancy, the linear relation of forward slip and tension, the state equation of continuous rolling, the formula of dynamic tension, and the formula of static tension have been obtained. These formulae reflect the functional relations between tensions, thickness, roll velocity, and time in the continuous rolling process. It is implied that the continuous rolling process is a gradually steady, controllable, and measurable dynamic system. An assumption of predicting the thickness of a steel plate using these tension formulae is also put forward.