自动充电机械臂运动学分析与样机试验

为了解决电动汽车自动充电过程中机械臂运动的稳定性以及定位精度的问题,利用ADAMS仿真软件对所设计的机械臂进行运动学仿真;根据D-H方法建立了机械臂运动学模型,通过蒙特卡洛方法分析了该机械臂的工作空间,利用MATLAB对机械臂工作空间进行求解,得到自动充电机械臂末端工作空间点云图。根据所设计的机械臂进行样机研制,并进行机械臂样机试验。结果表明,自动充电机械臂结构可行,运动合理,能够满足自动充电工作时的功能需求。该文的研究为机械臂的优化设计与运动控制提供了参考。     

隧道维修钢板安装机械臂设计与分析

针对隧道维修钢板安装的现状,设计一款七自由度的隧道维修钢板安装机械臂。利用SolidWorks软件对机械臂进行三维实体建模,为确保机械臂设计的合理性,运用SolidWorks与ANSYS Workbench相结合的方法对运动范围内极限工况下的机械臂进行静态和模态分析,得到应力应变云图和固有频率及其振型图。结果表明:机械臂结构强度满足设计要求,在工作中可以有效避免共振的发生。研究结果为机械臂进一步优化设计提供了参考。     

工业机械臂动力学模型简化分析与仿真

针对工业机械臂进行动力学分析的常用方法是利用Lagrange方程进行动力学建模后再实行仿真计算。利用Pieper准则,将五自由度工业机械臂动力学方程展开式简化,即将腕部与手抓部的关节视为外部干扰,只针对前三关节进行动力学分析;提出一种针对简化后的模型利用开源引擎ODE完成机械臂动力学计算;在建立的机械臂三维仿真平台上利用ODE进行仿真的方法。仿真结果表明:该仿真方法不仅可实现机械臂的实时控制,还能得到机械臂动力学参数曲线图。为解决机械臂动力学仿真中效率低和实时性差的问题提供了理论依据。     

一种多关节轻量化离散驱动机械臂的设计与研究

基于单马达驱动技术设计了一种5自由度的多关节轻量化离散驱动机械臂,机械臂各个关节采用离合器进行控制,多个关节共用一个驱动电机。针对机械臂特殊的传动链结构所造成的关节运动耦合特性,进行分析并提出了补偿措施。为研究机械臂的振动特性,利用ANSYS仿真软件对机械臂进行了模态分析,仿真结果表明机械臂激励频率远离其固有频率。通过对机械臂进行运动学正反解,并利用MATLAB进行仿真分析得到该机械臂能够通过关节联动的方式实现复杂运动轨迹。     

一种三自由度机械臂的设计与分析

设计了一种通用型三自由度机械臂,该机械臂的3个转动自由度相互垂直。详细设计了各关节的传动方案,并建立了系统的三维模型。根据机械臂的结构特点,建立了机械臂的D-H坐标系,对其进行正运动学分析。最后利用蒙特卡洛法对该机械臂的工作空间进行分析,得到机械臂末段执行器的工作空间,仿真结果与机械臂的设计参数相符,为该机械臂的优化设计及逆运动学分析奠定了基础。     

基于ADAMS和ANSYS的机械臂刚柔耦合运动学分析

针对机械臂的设计要求,设计了一种由两个铰链四杆机构组成的双自由度机械臂,利用ADAMS建立机械臂的刚性体模型,仿真得到不同时刻的运动参数曲线;利用ANSYS建立指定部件的柔性体模型,得到不同阶数的模态频率和模态振型值;利用ADAMS和ANSYS进行联合仿真后,得到机械臂的刚柔耦合模型,仿真结果表明:柔性体模型在z方向发生了微小位移变化,x、y方向位移波动范围增加了10 mm。利用Altium Designer软件绘制控制电路图并进行了实物制作,实验结果表明该机械臂具有广泛的适用性。     

六自由度串联机械臂运动学及其工作空间研究

根据实际生产需要设计和建立了一种用于焊接车间上下料的六自由度串联机械臂及专用末端执行器模型,针对机械臂的正运动学以及其末端执行器的可达空间进行了研究。基于D-H法对机械臂运动学数学模型进行建立并求得其正运动学方程。提出在Matlab环境下利用Robotics toolbox10.2通过代入各个关节随机参数的方法与机械臂正向运动学分析结果进行对比验证。基于机械臂末端执行器的可达空间与各个关节之间的对应关系,在Matlab中通过采用蒙特卡洛法对机械臂末端执行器的工作区域进行了分析,用描点的方式对机械臂末端执行器工作区域的点云图进行了描绘,通过对点云图的研究得出所设计机械臂结构较为合理的结论。     

自适应鲁棒控制在机械臂轨迹跟踪中的应用

以仿人型机械臂为研究对象,针对常规PID控制器在机械臂轨迹跟踪控制中存在速度较缓慢、位姿误差较大的问题,设计了一种自适应鲁棒控制策略。利用SolidWorks进行机械臂结构的自主设计,根据所设计的机械臂参数进行控制器设计,利用Simulink建立机械臂控制系统模型,在直线和曲线两种运动目标轨迹下进行轨迹跟踪控制验证。实验结果表明,相对于常规控制器该自适应鲁棒控制方法可以更为准确地控制机械臂的末端轨迹,跟踪速度快且跟踪位姿准确,具有较好的可行性及可移植性。     

3种材料在柔性机械臂振动抑制中的特性对比

在所设计的柔性机械臂的基础上,利用SolidWorks Simulation对合金钢、铝合金、碳纤维增强环氧树脂基复合材料3种结构材料的机械臂进行线性动态分析,分别从谐波分析和瞬态振动分析两个方面对机械臂进行仿真。结果表明,碳纤维增强环氧树脂基复合材料对机械臂具有明显的减振作用,其振动衰减速度及振动衰减效果要优于传统合金材料,为机械臂的设计及振动抑制提供了参考。     

液压支架油缸内壁缺陷修复机械臂的运动学分析与仿真

针对矿用液压支架油缸内壁局部缺陷修复,设计一种能深入液压支架油缸筒内进行内壁修复的焊接机械臂。基于改进D-H参数建模方法,对设计的内表面修复焊接机械臂进行运动学建模,并求解了内表面修复焊接机械臂的正、逆运动学。借助MATLAB软件,采用蒙特卡洛法,对该焊接机械臂的有效工作空间进行了仿真分析,利用Robotics Toolbox工具箱对油缸内壁缺陷修复机械臂进行关节轨迹规划,通过仿真得到各关节的角位移、角速度、角加速度曲线。仿真结果表明：该机械臂运行平稳,轨迹连续,满足运动学要求。     

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.     

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.     

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.     

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.