触摸屏自动贴合设备开发

针对触摸屏贴合工艺制程中多层复杂结构且较难实现特定标记的对位,开发出自动化影像伺服贴合生产设备。采用无标记影像对位技术,以区域影像拾取搭配归一化互相关算法的影像搜寻技术,实现自动搜寻与定位坐标拾取;以异空间取像设计影像自动对位系统,通过补偿控制参数最佳化后,能有效降低对位次数。测试结果表明:该设备能够实现多层组件的自动化精密对位贴合,贴合精度在100μm以内,生产良率达95%以上,符合行业生产规范要求。     

学习式运动控制在视觉引导机械手臂的应用

针对一般的机械手臂运动规划时只适用于特定的工作任务,无法即时与环境互动的问题,开发出多轴学习式运动控制结合影像技术的机械手臂,以胜任各种操作任务的需求。通过建立矢量积分到端点(Vector Integration to Endpoint,VITE)模型实现即时轨迹规划,并采用小脑模型控制器(CMAC)作为学习式控制器,以应对较为复杂的工作环境,利用两台二轴旋转焦距缩放摄影机估测目标物位置,运用NI的嵌入式数字信号处理器和影像采集卡,进行影像的拾取与手臂的控制。实验表明,该机械手能够根据目标物的影像实现即时追踪抓取,其运动轨迹与PD控制器相比,其误差较小,且控制更精准与平顺。     

基于模式识别的零件表面瑕疵图像提取的设计与实现

针对精密零件表面瑕疵处理问题,将计算机视觉技术用于精密零件表面瑕疵图像的提取和分析,提高了生产中机械零件自动识别的实时性和分拣的准确率,并结合嵌入式系统进行控制。设计了一个基于机器视觉的零件表面瑕疵图像自动识别系统,采用图像处理及模式匹配的方法,实现了零件表面瑕疵图像的提取,为零件表面瑕疵的处理做好了准备工作,达到了对许多加工件和产品表面质量进行快速检测的目的。     

搅拌摩擦焊对接拼缝间隙特征的在线检测方法

针对航天大型军工产品的搅拌摩擦焊接过程对对接拼缝焊接检测与控制的工程需求,提出了一种激光和视觉图像相结合的在线检测方法,以解决拼缝间隙0.2 mm的在线检测难题。该方法可实现焊前拼缝间隙量和错边量的精确、快速检测以及焊中实际焊缝位置跟踪。介绍了测量原理及检测方法,并详细阐述了拼缝间隙特征的自动提取技术,即面向搅拌摩擦焊焊缝特征影像的图像处理和数据处理方法,包括感兴趣区域提取、激光条纹轮廓提取、亚像素激光条纹中心提取、拼缝间隙特征提取等;结合五轴加工中心对测量系统进行试验验证,并与影像仪测量结果进行了对比。     

大尺寸工件细小孔视觉定位研究

针对大尺寸工件细小孔的视觉定位存在大视场检测精度低而小视场检测效率低的问题,提出一种基于机器视觉的单相机大尺寸工件细小孔位坐标的测量方法。该系统使用单相机4次采集,基于原点标记搜索拟合和动态计算孔位坐标的测量算法,考虑到机器视觉识别的局限性,设计易于识别的原点标记。利用采集到的带有原点标记的图像,通过对图像拟合、提取、比较分析等操作,获取原点坐标和X、Y轴的方向,以此对细小孔位坐标进行补偿,得到孔位坐标。最后以液晶显示器背板灯条螺丝孔为例,实验结果表明,该系统在检测960mm×550mm的液晶显示器背板时的最大误差为0.5mm,能够满足液晶显示器生产企业的要求。     

基于线扫视觉的活塞杆表面瑕疵检测系统设计

为提高活塞杆表面瑕疵检测效率,设计基于机器视觉的全自动活塞杆表面瑕疵检测系统。利用LabVIEW软件的Vision模块进行图像采集、处理与识别,利用TIA portal软件进行运动控制;利用二值化算法过滤掉较小瑕疵;对图像进行腐蚀运算,再进行膨胀运算,以去除孤立小点、毛刺和小桥。实验结果表明:该系统运行稳定、可靠且效率高。     

基于三维图像处理的车刀磨损缺陷检测方法研究

针对目前车刀磨损检测中所获取的二维图像处理无法提取车刀磨损区域三维特征的问题，提出一种基于结构光投影技术的方法，提取车刀磨损区域三维特征信息。对获取的信息进行分割，分离车刀中的垫片点云和刀头部分点云；然后对垫片点云进行最小二乘拟合平面处理，将拟合的平面与刀头部分点云进行最大距离求解，并用标准量块进行实际物理距离换算；最终获得刀头的最大实际磨损量，为工人更换刀头提供数据参考。实验结果表明：在对车刀进行磨损区域量化处理中，该方法可以获取车刀刀头的具体磨损量值，且具有较高的精度和较低的经济成本，该系统的误差小于0.05 mm,可满足实际生产需求。     

基于影像技术的弹簧零件外径尺寸的精密检测研究

弹簧的外径尺寸是其质检的重要指标,传统的弹簧零件检测效率不高、精度低,为此建立了一种基于影像检测技术的弹簧外径检测系统。介绍了影像检测原理及系统方案,包括影像采集系统的设计与选型、影像处理系统的设计方案等。对弹簧影像进行降噪滤波、边缘定位检测,提出了一种适用于弹簧外径的改进的圆形图元亚像素细分边缘检测算法。基于影像检测平台系统,对检测方法进行了实验验证,为弹簧外径在线实际检测应用打下了基础。     

10米重型数控单臂立车综合偏摆测量

针对某工厂10米重型数控单臂立车的综合偏摆,基于数据采集卡和LabVIEW软件建立了在线误差监测的虚拟仪器测量系统,并进行现场试验与应用。该系统硬件平台使用高精度电涡流传感器检测偏移距离,并采用滤波、均值和屏蔽等软件编程措施,实现了数据的处理、保存、报警及远程监控等功能。实验结果表明该测量系统能满足加工过程中对机床精度和稳定性的需求,有效地克服了现场干扰,保证了测量准确性,提高了设备精度检测及维修效率。     

辅助视觉下升降机平台人数超载智能检测方法（英文）

针对当前的升降机平台人数超载检测以人工为主,存在人为因素干扰、弊端较为明显的情况,提出一种基于计算机视觉图像的升降机平台人数统计方法。利用离散小波变换算法对采集的升降机平台图像进行去噪处理,通过高斯曲线拟合的方法进行人员头部图像特征提取,再根据人员头部与背景轮廓区域灰度值的变化是连续性的、工人轮廓与背景轮廓的纹理特征有差异性、工人轮廓边缘像素的灰度值存在梯度变化这3大特征,对人员头部进行分割,根据分割结果对人员特征区域进行标记和计数。结果表明:利用该方法能够准确地对升降机平台上的人数进行统计,误差低于5%,符合实际应用需求。     

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.     

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.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

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.     

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.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.