基于运动学的机器人轨迹规划研究

针对6自由度关节机器人轨迹规划问题,建立机器人的运动学方程,采用虚拟样机仿真的方法计算机器人各关节角速度和角加速度随时间变化的数据,同时采用拟合算法对数据进行轨迹化处理。建立了关节机器人实验平台,将关节空间轨迹规划参数运用到机器人上,使用激光跟踪仪测量机器人末端轨迹数据,通过机器人末端位置稳定时间和位置超调量来评估轨迹规划的有效性,实验结果表明:该方法所得轨迹平滑可控,可实现机器人按规划运行要求。     

打磨工业机器人轨迹规划仿真

为了研究打磨工业机器人的轨迹规划,使用D-H法建立机器人连杆坐标系,在MATLAB的环境下建立机器人三维模型,并在关节空间与笛卡尔空间进行了轨迹规划仿真,直观地显示出关节的变化情况与机器人末端在三维空间中运动的轨迹,结果表明对打磨机器人的轨迹规划是合理的,为打磨机器人沿着轨迹精确且平顺的运动提供了帮助。     

基于时间最优的机器人关节轨迹规划方法

工业机器人在精密装配领域正在朝着装配速度更快、精度更高以及轨迹最优方向发展。为此,基于平滑轨迹生成模型,提出一种新的工业机器人关节轨迹规划方法。该方法结合工业机器人特定的装配任务和每个关节的特定移动配置方式在机器人运动链上进行优化,采用多变量时间优化方法优化机器人各关节运动轨迹,进而最小化机器人的总体执行时间,达到时间最优,提高装配效率的目的。多变量时间最优机器人关节规划方法在光电工业的模块化机器人上进行了测试。实验结果表明,工业机器人关节轨迹优化方法能够有效提高机器人装配效率,相比传统轨迹规划方法能够缩短39%的执行总时间,证明了该方法对工业机器人平滑轨迹生成的有效性。     

机器人视觉跟踪两维运动目标的方法研究

讨论了机器人视觉跟踪两维运动目标的方法。用基于图象的视觉伺服方法来预测特征点在图象平面的运动轨迹。根据这个预测和机器人的当前位姿来预测机器人的各关节运动变量。在开放式机器人控制器中，用三次样条函数来平滑离散规划位置，以避免跟踪运动中的振荡。     

基于MATLAB Robotics Toolbox的UR5机器人轨迹规划与仿真

为了解UR5机器人实时轨迹变化情况,根据Denavit-Hartenberg参数法在MATLAB Robotics Toolbox中利用Link函数建立了UR机器人的三维数学模型,对UR5机器人进行了正、逆运动学求解与理论分析,推导出各个关节角之间的变化关系;利用三次多项式插值法对任意PTP (点到点)之间的空间轨迹规划进行理论分析,并结合MATLAB Robotics工具箱对UR5机器人数学模型进行了空间轨迹规划和仿真,得到了连续变化的轨迹曲线。仿真结果验证了机器人运动学模型的正确性和合理性,为UR系列机器人的进一步研究和应用提供了理论依据。     

基于焊接机器人的关节空间轨迹规划方法

针对"昆山一号"机器人关节空间运动的实际需求,结合机器人实时轨迹插补算法,提出了关节空间轨迹规划方法.运用离线编程软件仿真得到机器人末端运行轨迹,路径平稳连续.通过MATLAB 仿真得到机器人各个关节角度变化曲线和关节速度变化曲线,关节角度曲线平滑连续,关节速度曲线合理无突变.关节空间规划方法也可以应用在由变位机、导轨和机器人组成的多轴系统中,运行轨迹连续稳定,速度曲线满足工艺要求.该方法应用于"昆山一号"焊接机器人中,满足焊接实时调速和实时调整轨迹的需要.规划结果表明关节空间规划方法是合理正确的.     

码垛机器人运动学分析及关节空间轨迹规划研究

以IRB-460工业机器人为研究对象,针对其运动学建模及在笛卡尔空间和关节空间下的轨迹规划方法展开研究并进行对比。对机器人本体进行了机器人运动学分析,利用多项式轨迹插值算法进行了关键点间的轨迹规划,完成了重叠型码垛的作业流程。利用Robotics Toolbox完成了轨迹规划算法仿真,并进行了结果分析。仿真结果表明在关节空间下进行轨迹插补所得的路径点更为优化,所得的轨迹更为满足作业任务,具备合理性。     

六足机器人腿部最优时间轨迹规划

为了提高六足机器人腿部控制的平稳性、动作快速性,利用五次B样条曲线进行关节空间轨迹规划,从而使关节运动的速度、加速度和脉动连续。利用B样条曲线的凸包性把腿部关节速度与加速度约束转化为对曲线控制顶点的约束。通过MATLAB遗传算法工具箱对运动轨迹进行时间优化,利用罚函数解决关节约束问题。仿真结果表明:该轨迹规划方法有效且可行。     

基于MATLAB Robotic Toolbox的关节型机器人运动仿真研究

在MATLAB环境下对关节工业机器人进行仿真分析。以ER3A-C60机器人为例,分析了它的正运动学、逆运动学和轨迹规划问题。利用Robotics toolbox和D-H参数建模方法,建立该机器人的运动学模型,进行该机器人轨迹规划的仿真,得到机器人关节角、角速度、角加速度随时间变化曲线,验证该机器人参数的合理性.     

基于ROS的工业机器人轨迹规划和仿真

针对工业机器人轨迹规划算法实现困难、运动过程存在柔性冲击的难题,通过对主流机器人操作系统ROS(Robot Operating system)的研究,提出一种在ROS系统下的轨迹规划的方法。实现了六轴工业机器人在笛卡尔运动空间和关节空间理想的运动轨迹,通过优化的S形轨迹规划算法得到的关节速度、加速度、加加速度变化平滑,保证了机器人运动过程的快速平稳,有效降低了柔性冲击。并通过RViz对机器人进行仿真,仿真结果和关节角度曲线图符合预期效果,表明了此方法的可行性。     

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.     

Bulletin of the Awards in 2013

<正>Five reviewers and 9 published articles are selected as the Excellent Rewewerand Excellent Article in 2013 respectively.Excellent Reviewers:Prof.Z ongyi Ma(Institute of Metal Research,CAS,C hina);Prof.Y ongbo Xu(Institute of Metal Research,CAS,C hina);Prof.Guangping Zhang(Institute of Metal Research,C AS,C hina);Prof.Z hendui Cui(Tianjin University,China);