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。     

精准装配模式研究

把精益生产的思想应用于装配过程，改变传统制造业装配的模式，从而产生了精准装配的概念。通过精准装配来实现装配过程的精益化、产品质量的最优化和产品的可定制化，以适应当前制造业的小批量、多品种、面向客户的生产模式。在提出了精准装配概念的基础上，对精准装配的必要条件、实现方法和精准装配的结果进行了初步的探讨。     

基于割集算法的车削夹具虚拟装配序列规划

目前航空航天企业产品结构复杂,零部件数量众多,且在实际加工过程中需要大量的夹具。针对小批量、多品种的生成模式,快速准备符合加工要求的夹具是航空航天企业急需解决的问题。应用装配关联图为基础,描述某车削夹具的装配信息模型,结合割集算法的技术,设计并实现了产品的虚拟装配序列规划,并对生成的装配规划进行评价。应用该装配序列规划方法可实现夹具的快速工装,明显提升生产效率。     

面向多品种小批量的工序质量控制系统

市场发展和客户需求的多样化,使得多品种小批量生产成为主要生产方式,但是传统质量控制方法在小批量生产中的应用遇到困难,为了解决传统的质量控制技术在多品种小批量应用中难以解决的问题,在分析其加工特点与质量影响因素的基础上,提出对小批量生产方式进行质量控制的思想和策略,将质量控制的目标从产品转向工序,提出一种面向工序,基于质量预防、制造过程的质量诊断与分析改进的工序控制系统,对生产工序进行控制,确保制造过程处于稳定状态.     

基于视觉的工业机器人装配演示示教研究

针对工业机器人编程效率低下、智能化程度不高和人机交互性能弱等问题，提出一种基于视觉的工业机器人装配演示示教系统，该系统包括目标检测与中心点定位模块、装配动作分类识别模块和机器人动作执行模块。在目标检测与中心点定位模块中,提出一种目标物体中心点定位和机器人抓取方法，使用实例分割算法识别物体类别，通过掩码均值化处理和坐标转换计算物体3D姿态信息；在装配动作分类识别模块中，建立基于深度学习网络的动作分类识别模型，该模型的输入为装配动作视频帧，输出为动作分类标签；最后，机器人动作执行模块根据物体类别、物体3D姿态和动作分类标签等信息规划机器人装配动作，控制机器人执行装配任务。以轴孔装配为例，验证了上述方法的有效性，实现了基于视觉演示的机器人装配模仿编程，对机器人演示示教研究具有一定的参考价值。     

融合视觉和以太网技术的工业机器人分拣装配控制系统设计

针对制造业中多类型、多工位、无规则、有残次工件人工分拣出错率高与装配效率低下的问题,设计一个融合视觉和以太网技术的工业机器人分拣装配控制系统.应用工业以太网构建一个包含视觉、PLC、HMI和工业机器人的硬件系统;提出结合图像匹配、圆孔识别算法的工件检测与识别方法;基于坐标偏移的方法设计了一个PLC控制工业机器人的优化算法;并对工业机器人进行示教与编程,实现工件正确分拣与高效装配.测试证明:该系统工件识别正确率达100％,工业机器人的示教位置大大减少,工业机器人的控制程序明显简化,工件分拣正确率与装配效率显著提高.     

产品协同设计过程冲突预消解研究

产品设计过程冲突是不可避免的,冲突消解可以分为两个阶段,即冲突预消解和冲突检测消解.合理地进行设计任务分解与规划,将从根源上消除可能出现的过程冲突,实现冲突预消解.基于CCM_A(Cooperating Correlative Map Base on Activity)过程建模新方法,确定冲突预消解的图示表达;根据产品协同设计特点,建立相应的任务分解规划层次模型,确定了产品协同设计任务分解与规划约束规则,确定了协同设计任务的层次分解与规划方法与步骤;以设计信息协同为基础,提出设计任务间协同度的概念,并对其进行定义和量化表达;提出基于协同度的大粒度耦合任务集撕裂规划方法,并进行实例应用.     

多机器人系统协同作业策略研究及仿真实现

机器人技术作为现代高新技术之一,在各行业得到了蓬勃的发展和广泛的应用,大大促进了生产力的发展。在任务复杂时,单机器人无法胜任,就需要多机器人协作来完成工作。各子机器人协同合作时,并不是简单的功能叠加。多机器人系统求解任务就是通过寻找系统联盟中能够执行任务的一个或多个机器人,并且该机器人组合是完成该任务时代价最小的一个组合。作者根据任务类型不同,把多机器人的协作形式划分为顺序协同、同步协同和自由协同3种形式,通过设计的优化算法,研究了3种形式下如何协同规划及路径优化,并经仿真实例验证了方法的可行性、正确性。     

多机器人系统布局与时间协同优化

多机器人系统能可靠地完成单机器人无法完成的高效性作业,已成为构建智能产线的研究热点。但是在协同优化和时间成本上还存在许多问题。针对多机器人装配系统布局优化问题,在分析ABB机器人系统的正逆运动学理论和构建多机器人模型与数学建模的基础上,提出了基于粒子群算法的多机器人系统布局优化方案,并采用MATLAB进行逆运动学求解。通过仿真实验验证了粒子群算法的有效性,该方法可减少多机器人系统的运行时间,节时13.48%,显著提高系统的运行效率,对以后多机器人系统任务分配以及路径规划的研究具有重要意义。     

基于GBO-LSSVM的多品种小批量产品质量预测北大核心

针对多品种、小批量产品在生产过程中存在影响产品质量的不确定因素等问题,提出了GBO和LSSVM相结合的多品种、小批量产品质量预测模型;模型采用LSSVM对产品加工过程进行量化分析,并使用GBO算法对LSSVM模型中的惩罚函数与核函数寻优;最后通过MATLAB仿真对GBO-LSSVM优化方法与其他预测方法进行分析对比。结果表明,GBO-LSSVM模型更适用于多品种、小批量质量预测问题,以提高预测精度与误差水平,为多品种、小批量生产模式质量预测打开新思路。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

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。     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.     

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.