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。     

悬臂式3D打印机器人运动分析与打印实验

针对目前3D打印装置结构单一和打印空间小的的缺点,研制了一台悬臂式3D打印机器人.运用D-H(Denavit-Hartenberg)法建立连杆坐标系,根据齐次坐标变换,建立机器人正运动学方程,采用代数法进行逆运动学求解,通过控制各关节变量,驱动打印头在3D打印平台上按照指定轨迹实现3D打印功能,并在悬臂式3D打印机器人实验平台上进行了零件打印实验,结果表明:所设计的悬臂式3D打印机器人能够准确、有效的按照规划路径执行相应轨迹运动,表面无翘曲和变形产生,打印零件质量和精度较高.     

六自由度机械臂运动学及工作空间分析

建立了一种用于危险作业条件下的六自由度机械臂模型,根据D-H方法建立了其数学模型,并进行正向运动学分析,通过计算和仿真,验证了所建运动学方程的正确性。通过采用蒙特卡洛法分析该机械臂的工作空间,利用Matlab对机械臂工作域进行求解,给出了机械臂末端的工作空间点云图。通过机械臂运动过程中基座的受力分析,结果表明:末端执行器移动速度越快,基座承受的力矩越大;各个关节角速度和末端执行器移动速度对力矩曲线的平稳性影响明显,且基本成正比;在末端执行器位移方向改变处,基座所受力矩最大。     

铸件多功能作业机器人多臂协调轨迹规划与仿真

以铸件多功能作业机器人的工作臂为研究对象,采用笛卡尔空间变量法对机器人铸件搬运过程进行轨迹规划。结合多臂协调的运动约束条件以及伪逆法,对机器人的4个工作臂关节运动进行优化,得到多机械臂协调运动的关节位置和速度变化曲线。由MATLAB软件仿真得到的运动参数曲线可知,算法优化后得到的运动轨迹均能保持连续、平滑,有利于实现对机器人的精准控制。利用机械臂正运动学方程得到了机械臂末端执行器的轨迹曲线,曲线满足铸件搬运的要求,验证了算法的正确性。     

一种悬臂式3D打印机器人的路径规划研究

针对目前3D打印装置结构单一和打印空间小的的缺点,研制了一台悬臂式3D打印机器人。运用D-H(Denavit-Hartenberg)法建立连杆坐标系,根据齐次坐标变换,建立机器人正运动学方程,求取机器人末端打印喷头相对于世界坐标系的位姿。采用代数法进行逆运动学求解,通过控制各关节变量,实现3D打印机器人各轴联动,驱动打印头在3D打印平台上按照指定轨迹实现3D打印功能。该3D打印机器人具有多角度多工位打印的特点,并能够在工作现场打印零件。对3D打印的路径进行规划,提出了一种基于蚁群算法和改进的近邻法进行轮廓路径规划的方法,并运用该方法在悬臂式3D打印机器人实验平台上进行了零件打印实验。与传统的zigzag法和repetier-host法比较,单层的轮廓路径长度分别缩短了19.5%和14.7%,打印时间缩短了12.6%和8.8%,结果表明,该路径规划方法的打印效率更好。     

悬臂式3D打印机器人运动分析与打印实验（英文）

针对目前3D打印装置结构单一和打印空间小的的缺点,研制了一台悬臂式3D打印机器人。运用D-H(Denavit-Hartenberg)法建立连杆坐标系,根据齐次坐标变换,建立机器人正运动学方程,采用代数法进行逆运动学求解,通过控制各关节变量,驱动打印头在3D打印平台上按照指定轨迹实现3D打印功能,并在悬臂式3D打印机器人实验平台上进行了零件打印实验,结果表明:所设计的悬臂式3D打印机器人能够准确、有效的按照规划路径执行相应轨迹运动,表面无翘曲和变形产生,打印零件质量和精度较高     

基于ADAMS的六自由度串联机器人运动学仿真研究

借助ADAMS仿真软件建立了六自由度串联机器人的虚拟样机模型,对其运动学问题进行了仿真研究。通过对末端执行器添加点驱动,设置期望轨迹参数方程,仿真测量得到各个关节角度变化的曲线,通过对曲线的拟合,最终得到运动学逆解。利用六个关节的运动驱动,仿真得到机器人末端执行器的位移与速度曲线,其变化平稳,无突变现象。通过在ADAMS平台上进行仿真,可直观的了解到机器人运动过程中的各连杆、各关节及末端执行器的运行状态,为机器人轨迹规划、动力学分析及离线编程、物理样机实验等提供依据。     

高速冲压生产线上下料冗余机械臂的运动学分析

在应用于高速冲压生产线冗余机械臂姿态规划和轨迹优化过程中,以兼顾上下料效率与轨迹的平稳性为目的,对冗余机器臂的加加速度进行约束,基于旋量理论建立运动学模型,得到正运动学方程,采用遗传算法对冗余机械臂进行逆运动学分析,结合五次B样条插值方法,对末端执行器运动轨迹的加加速度进行优化。结果表明,该方案可有效提高上下料效率,保证冗余机械臂上下料过程运行平稳。     

一种五轴冗余工业机械臂运动分析及仿真

冗余机械臂凭借广泛的运动空间、较高的灵活度等优势得到了广泛的关注,但其逆运动学求解复杂,计算量大。针对此问题,以某五轴冗余工业机械臂为例,根据D-H约定建立正运动模型,结合实际情况确定关节运动顺序,基于代数法建立逆运动求解模型,降低求解的复杂性,计算结果满足轨迹规划的要求。并基于关节空间采用五次多项式函数进行运动仿真验证,结果表明:各关节运行平稳,没有明显的突变点,满足机械臂的工作需求。     

基于摆缸关节的液压机械臂运动学及工作空间分析

针对传统机械臂输出转矩较小的问题,设计了基于叶片式液压摆动油缸(摆缸)作为关节的6自由度液压机械臂,该液压机械臂具有诸多优势,其最大的优点是具有很高的负重比。运用改进的D-H法建立了该液压机械臂的运动学模型,得出其正运动学方程。在MATLAB中进行了液压机械臂的轨迹规划仿真,得到了各关节转角的特性曲线,验证了液压机械臂结构设计的合理性。利用蒙特卡洛法分析计算了其工作空间,借助MATLAB绘制了其末端执行器的工作空间云图,为今后液压机械臂的深入研究提供了重要依据。     

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.