基于改进蜂群算法的焊接机器人路径规划方法研究

针对焊接机器人的运动特点及焊接工作过程中焊枪的避障问题,提出基于改进人工蜂群算法的机器人避障焊接路径规划策略。首先针对传统人工蜂群算法存在的问题,将Lévy(莱维)分布引入到人工蜂群算法侦查蜂寻找新蜜源的过程中,代替其原有0～1之间的随机分布过程,形成了基于Lévy飞行的改进型人工蜂群算法,然后将其应用到焊接机器人的路径规划问题中,并进行了仿真实验。结果表明:改进后的方法能够得到最优的焊接避障路径,且寻优速度快、过程稳定。该方法可用于解决焊接机器人避障路径规划问题。     

双焊接机器人协同路径规划研究

针对白车身侧围双机器人协同焊接路径任务,对焊接路径规划算法进行研究,提出一种基于蚁群粒子群的融合算法。首先,建立单机器人焊接模型,将焊接任务转换为TSP问题,采用提出的融合算法优化TSP问题并与多种路径规划算法进行对比分析,证明所提出算法的优越性;其次,根据焊接任务将双机焊接转换为MTSP问题,依据约束条件,将MTSP转换为多个TSP问题,利用焊接路径之间的关系更新焊点,完成双机器人协同焊接模型建立,在MATLAB中得到路径规划的结果;最后,在ROBCAD中建立双机器人焊接工作站,对规划结果进行仿真验证。实验结果证明,所提出的融合算法对于双焊接机器人路径规划具有一定的指导作用。     

基于人工蜂群算法的机器人路径规划

为求解机器人路径规划问题,引入人工蜂群算法,并将路径空间以网格划分,通过固定起始节点和设定最大允许路径节点数等方法,解决了人工蜂群算法应用于路径规划的两个难题--路径节点不固定和邻域构造困难,实现了将ABC算法应用于路径规划问题.通过典型的实例仿真对算法性能进行测试,结果表明:该算法有效克服了停滞行为的过早出现,而且能够加快收敛速度,得到全局最优解或近似解,是解决机器人路径规划问题的一种有效算法.     

大型三维复杂构件双机器人协同焊接智能路径规划方法

大型三维复杂构件是船舶、海洋装备、集装箱等的重要组成部分,其焊缝种类较多、空间分布复杂,部分焊缝存在协同同步弧焊焊接、焊接方向等特殊焊接工艺约束,现有协同焊接规划方法难适用于这类复杂场景。提出全局与局部相结合的双机器人协同焊接路径规划多阶段寻优方法;建立复杂构件三维空间焊缝模型以及双焊接机器人协同模型;根据协同同步焊焊缝的数量将构件划分出相应数量的分块,通过蚁群算法求解每一焊接分块的局部路径规划近似最优解;通过遗传粒子群算法进行多分块间的全局路径规划。仿真结果表明:通过分块划分多阶段寻优的方法可以有效地解决特殊焊接工艺约束下的大型三维复杂构件双机器人同步焊接路径规划问题。     

基于人工势场法的管件切割路径规划

大型船厂对管件的切割焊接中,采用机械臂的自动切割、焊接及其编程规划问题是亟待解决的问题.阐述了基于人工势场的割枪切割管件的运动路径规划方法.在切割路径规划中,定义引力函数和斥力函数,通过MATLAB科学计算程序实现了所提出规划算法,并应用于Kuka机器人.仿真结果表明,所规划的机器人末端轨迹的准确性和可行性.     

一种求解机器人路径规划的智能优化算法

为了解决汽车白车身焊接机器人路径规划不合理的问题,将路径规划问题抽象为TSP问题的数学模型,分析了蚁群算法并将该算法应用于求解该问题.采用Matlab语言时典型的机器人焊接路径规划实例进行编程仿真,结果表明:不仅能够克服早熟现象,而且能够加快收敛速度,可以有效快速解决焊接机器人路径规划问题.     

机器人远程激光焊接离线编程系统与路径规划

由于远程激光焊接过程中焊接顺序和机器人路径规划对于焊接周期影响较大,因此文章提出了离线远程激光焊接编程系统。该系统以扩增实境为基础,通过3D输入设备可以实现机器人轴的快速定位,提出了以解决旅行商问题的轨迹优化算法,对机器人路径以及焊接顺序进行了优化。离线远程激光焊接编程系统不仅仅能够实现快速的空间人机交互,还具有很高的适用性,操作简单。经仿真结果可以得出,离线编程相比传统的在线编程能够节省30%的焊接时间,极大地提高了远程激光焊接效率。     

基于APG算法的多焊接机器人路径规划研究

为解决多机器人同步焊接路径规划不合理问题,提出一种基于蚁群的融合算法（APG）。首先将多机器人路径规划问题转换为MTSP数学模型,使用kmeans算法将MTSP问题转换为多个TSP问题;其次采用提出的APG算法来优化TSP问题,同时与ACO算法和PSO_GA算法进行实验结果对比,证明APG算法的优越性;最后在ROBCAD中建立三维模型,对可达性、干涉性等实际应用中存在的问题进行仿真,验证算法的有效性。实验结果表明:所提出的APG算法同其它路径规划算相比能够得到更佳路径。     

基于APG算法的多焊接机器人路径规划研究（英文）

为解决多机器人同步焊接路径规划不合理问题,提出一种基于蚁群的融合算法(APG)。首先将多机器人路径规划问题转换为MTSP数学模型,使用kmeans算法将MTSP问题转换为多个TSP问题;其次采用提出的APG算法来优化TSP问题,同时与ACO算法和PSO_GA算法进行实验结果对比,证明APG算法的优越性;最后在ROBCAD中建立三维模型,对可达性、干涉性等实际应用中存在的问题进行仿真,验证算法的有效性。实验结果表明:所提出的APG算法同其它路径规划算相比能够得到更佳路径。     

双机器人协调点焊路径优化算法研究

针对双机器人协调点焊白车身前门的焊接路径研究,提出一种多目标遗传算法的点焊路径优化方法。所提算法利用机器人平稳性函数、焊点质量函数、焊钳的可操作性函数以及协调碰撞检测函数,可以实现双机器人协调焊接路径规划,通过分析由于焊钳位姿无法精确控制而引起焊点质量问题,提出了焊钳法向调姿方法,通过对白车身结构件车门窗围25个焊点分布属性及双机器人协调运动焊接要求进行分析,利用齐次变换矩阵和机器人逆解公式求得机器人各个关节角变化量,在Matlab得到双机器人协调运动柔顺焊接路径结果。最后,在机器人离线编程软件RobotStudio建立双机器人协调焊接工作站,对规划结果进行仿真试验验证。结果表明,该方法可以在实际焊接环境中实现双机器人协调点焊路径规划,对提高焊点质量与焊接效率奠定了理论基础。     

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.