基于统计决策的GMAW焊穿缺陷在线检测

焊穿是汽车零部件焊接生产的主要缺陷之一.为实现焊接产品质量的"零缺陷"以及生产过程质量监控的目标,提出了一种基于最小二乘(LS)预报和统计决策方法的GMAW焊穿缺陷在线监测方法.     

基于主元空间数据分布比较的统计过程监测

过程数据的分布特性涵盖了过程运行状态的有效信息,据此通过对主元子空间数据分布结构的分析比较,提出一种新的在线连续过程监测方法.与传统的多变量统计过程控制(MSPC)方法相比,该方法通过定量评估主元子空间中数据集的质心偏移以及数据集的分布方向2个监测指标来揭示数据分布结构的不同,对过程稳定运行点以及变量间相关性的变化作出准确判断,从而实现了对过程运行状况的实时监测和故障诊断.仿真例子验证了该方法的有效性和可行性.     

如何正确选用并有效实施统计过程质量控制

该文在对多家国内日资制造企业和国内领先制造业统计过程质量控制(SPC)应用情况调查的基础上,针对统计过程控制实施过程中的主要问题,从统计过程控制实施前的准备工作、非传统控制图的选用、控制图实施主要三个方面,论述了如何通过提高统计过程控制的应用效率为企业真正创造价值。     

弧焊机器人熔化及气体保护焊熔池视觉自适应检测

采用新型互补金属氧化物半导体(Complementary metal oxide semiconductor, CMOS)视觉传感器对弧焊机器人熔化及气体保护焊(Gas metal arc welding, GMAW)熔池图像的提取技术进行研究,通过对CMOS视觉传感器的硬件电路改造,实现GMAW熔池图像的自适应采集.首先对触发电路进行改造,实现熔池图像高速采集的可控化.对GMAW脉冲焊不同时刻采集的熔池图像进行比较,定性得到最佳的采集时刻.对硬件控制电路进行改进,实现熔池图像曝光量的可控化.研究GMAW在送丝速度协同控制模式下,不同送丝速度与曝光量的定量关系.通过对硬件控制电路进行改进,实现熔池图像灰度压缩的可控化.比较CMOS视觉传感器工作在不同模式下对GMAW脉冲和短路焊时采集的熔池图像,得出CMOS视觉传感器工作在线性-对数模式下能更好地适应GMAW熔池图像采集.最后综合运用以上3种技术对GMAW脉冲焊和短路焊的熔池图像进行试验,均获得了清晰的熔池图像,为下一步熔池图像处理和焊接质量控制打下了基础.     

基于主元分析的生产过程质量控制与诊断

针对生产过程中监控变量的波动、故障及过程扰动对生产稳定性及可靠性影响情况下,常规统计过程控制图无法准确识别缺陷的问题,结合主元分析模型设计质量监控图以对生产过程中影响质量的因素进行控制与诊断。通过介绍主元分析模型,利用主元子空间和残差子空间反应的数据变化测度,结合统计控制图技术设计集成生产过程控制模型对生产过程质量进行监控,提出了基于主元分析模型的生产过程控制与诊断流程,对生产中的扰动进行诊断与识别。     

基于SPC与EPC集成的制造过程质量监控与调整

针对质量监控与调整中噪声信息对测量数据质量影响的问题,提出了一种基于统计过程控制（SPC）与工程过程控制（EPC）集成的制造过程质量监控与调整方法。建立了基于波动状态的统计过程控制与工程过程控制集成模型,实现了在质量监控的同时进行波动补偿。在质量监控阶段,首先采用Kalman滤波方法对含有噪声信息的测量数据进行滤波处理,估计得到波动状态,再依据滤波状态建立指数加权移动平均控制图进行质量监控,通过平均运行长度验证了该质量监控方法的性能。在质量调整阶段,基于波动状态对制造过程进行了调整。运用生产实例验证了方法的有效性和准确性。     

电机振动的质量检测与控制系统

设计了电机振动速度的在线自动检测与质量控制系统。通过电涡流传感器对工件的振动速度进行采集,经过以计算机为核心的控制系统的计算,利用休哈特控制图和过程能力指数等统计过程控制工具,通过人机界面实时显现,并根据闽值报警,实现对电机振动速度的质量控制。     

先进制造环境中工序质量统计过程控制的地位与作用

针对先进制造环境不仅要求技术上具有先进性，更重要的是其理念上具有先进性的特点，从工序质量统计过程控制(SPC)与自动过程控制(APC)关系的视角及质量改进的角度，论证了SPC在先进制造环境中的重要性，提出SPC是先进制造环境中重要组成部分的观点，指出其表现形式将是自动的SPC系统。先进制造环境中新的质量观要求将SPC实现计算机化、网络化及集成化，而SPC系统为在先进制造环境中新质量观的实现，提供了有力的物质保障与支持。     

焊接工作站在大型薄壁类箱体的应用

大型薄壁类箱体在焊接过程中,焊缝密集、焊接件数量多、焊接变形控制需要工装保证。为了减少人工劳动强度、提高生产效率、控制产品变形,某箱体应用CLOOS焊接机器人实现大型薄壁类箱体的自动焊接。在手工MAG焊接成熟的工艺参数基础上,对CLOOS焊接机器人进行自动焊接研究并应用于大型薄壁箱体。通过设计焊接胎具工装、调整焊接程序和参数,实现了机器人对该产品的蒙皮纵焊缝,以及数量密集的横筋角焊缝的焊接。在保证焊接稳定性的前提下,焊接程序加入喷嘴传感器和焊缝区域性变量循环,焊后焊缝成型良好,焊缝质量满足磁粉探伤要求,降本增效,满足生产质效需求。     

基于SPC的焊接生产线质量控制及相关分析

结合统计过程控制(SPC)和相关分析的内容对焊接生产线进行过程能力的统计计算、生产线稳定状态的分析、质量控制影响因素和故障原因及表现的相关分析,并针对生产线提出有效的改进方案,使生产线系统改善了SPC的稳态,减少了焊接生产线的故障率,提高了生产线的响应能力和生产质量,并以某汽车后桥焊接生产线为实例进行了验证.     

ON LINE MONITORING OF BURNING THROUGH FOR SHORT CIRCUIT CO_2 ARC WELDING BASED ON THE SELF-ORGANIZE FEATURE MAP NEURAL NETWORKS

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Weld quality analysis and evaluation of plasma arc welds in electrical stators

The use of plasma arc welding (PAW) has increased in the last years as a substitute for the gas tungsten arc welding in the automotive, electrical and appliance industries. Although the use of PAW in the industry has increased, there are still a limited number of theoretical methods and simulation tools to predict the metal flow characteristics and its interaction with the process parameters during the welding process. Therefore, weld design must still rely on the designer’s experience and the trial-and-error method. As a consequence, the process parameters and the weld quality may not be as originally expected at the design process. In this paper, a weld quality analysis of the PAW process is presented to guarantee a good quality of the product. To measure the influence of process parameters on weld quality, first, “quality” is defined. Weld quality measurement methods are then proposed based on visual inspection, electrical tests and mechanical tests of the welds. Using these methods and the experimental data obtained from the actual welding process at the production line, a new approach to evaluate the weld quality is proposed based on a circular shape model of the weld cross-section area. Finally, a relationship between the weld geometry and weld quality is proposed and intended to be used as a practical online monitoring method of weld quality.     

模式识别在机械自动化制造过程中的质量监控

为降低机械自动化制造过程中的废品率,提出模式识别在机械自动化制造过程中的质量监控方法,监控自动化制造过程中的产品质量,提高对产品质量的识别精准度。基于机械自动化制造过程中的质量检测环节,创建机械自动化制造过程中的产品质量监控流程。采用数字化测量仪采集机械自动化制造生产线质量数据,创建 SPC 控制图。基于 SPC 控制图模式识别的质量监控方法,将 k-means 算法与粒子群算法相结合,利用改进 k-means 算法获取控制图模式产品质量数据集聚类中心,结合欧氏距离,提取 SPC 控制图距离特征。将其输入多分类的支持向量机中,识别机械自动化制造过程中的产品质量控制图模式类型,诊断异常因素,并采取相应调控措施,实现机械自动化制造过程中的质量监控。实验表明:该方法可有效提高控制图的识别精准度,缩短训练与测试时间;并有效监控机械自动化制造过程中的产品质量。     

[制造与维修工艺]钢轨焊接接头精密整形工艺及方法

提出了一种以铣代磨的钢轨焊缝精密修整工艺原理及方法,设计了钢轨焊缝精铣机。该精铣机可实现钢轨轮廓的非接触式高精度测量、铣削路径自动规划、铣削量自动控制以及加工质量的在线监控等,消除了传统磨削加工中因温升大而导致的钢轨晶体结构破坏、焊缝接头二次形变等问题,提高了无缝钢轨的生产效率与质量,在焊缝加工精度、效率、环保等方面均优于进口精磨机。     

马鞍形焊缝焊接运动轨迹的自动控制

针对两相交管材所形成的马鞍形焊缝的特点,设计用于相交管材相贯线焊缝自动焊接的控制系统,并给出该系统的机械传动机构的工作原理、电气结构和软件实现方法.实验证明:该自动焊接系统在钢制散热器管道焊接过程中取得了良好的效果,是一种低成本马鞍形焊缝专用焊接设备,并且通过改变焊缝曲线数学模型,可用于其他形状管道接缝的焊接.     

通信铁塔塔靴自动焊接系统设计与应用

针对通信铁塔塔靴拼装、焊接的工艺特点,研发了铁塔塔靴自动焊接系统。焊接设备通过取板机械手与变位机相互配合完成板料精确拼装,通过取板机械手、变位机、焊接机器人的联合作业,实现塔靴自动焊接,现场试用情况表明该自动焊接系统可自动拼装焊接多种型号的塔靴,且焊接效率高、焊接质量好。     

Discerning Weld Seam Pro les from Strong Arc Background for the Robotic Automated Welding Process via Visual Attention Features

In the robotic welding process with thick steel plates, laser vision sensors are widely used to profile the weld seam to implement automatic seam tracking. The weld seam profile extraction(WSPE) result is a crucial step for identifying the feature points of the extracted profile to guide the welding torch in real time. The visual information processing system may collapse when interference data points in the image survive during the phase of feature point identification, which results in low tracking accuracy and poor welding quality. This paper presents a visual attention featurebased method to extract the weld seam profile(WSP) from the strong arc background using clustering results. First, a binary image is obtained through the preprocessing stage. Second, all data points with a gray value 255 are clustered with the nearest neighborhood clustering algorithm. Third, a strategy is developed to discern one cluster belonging to the WSP from the appointed candidate clusters in each loop, and a scheme is proposed to extract the entire WSP using visual continuity. Compared with the previous methods the proposed method in this paper can extract more useful details of the WSP and has better stability in terms of removing the interference data. Considerable WSPE tests with butt joints and T-joints show the anti-interference ability of the proposed method, which contributes to smoothing the welding process and shows its practical value in robotic automated welding with thick steel plates.     

Three-dimensional vision-based sensing of GTAW: a review

Automated and robotic welding is now widely used in manufacturing industry. The control of the welding process plays a crucial role in producing quality welds in automated and robotic welding where the assistance from skilled welders is no longer available. In gas tungsten arc welding (GTAW) which is the primary arc welding process for precision joining of metals, the weld pool is the major source of information that can be used to assure the production of desired weld penetration which is the most critical factor determining the weld integrity. To meet this challenge, various sensing technologies have been proposed/studied to sense and obtain the feedback for the weld pool state. This paper summarizes the researches on weld pool state sensing: conventional sensing technologies, vision sensing technology, and multi-sensor information fusion technology, with emphasis on the analysis of three-dimensional vision sensing methods. And three-dimensional vision sensing, multi-sensor technology, intelligent modeling, and effective commercial product development show the future trends of GTAW penetration sensing.     

基于焊枪与熔池耦合模型的焊工调控行为研究

模拟解析有经验高级焊工焊接行为并实现抽象焊接行为的程序化无疑是快速发展机器人智能化焊接的优选路径之一。而同步传感测量焊工焊枪姿态和熔池状态是实现焊接行为程序化的关键。针对现有焊枪姿态和熔池特征测量系统的独立性及焊工与熔池交互过程的同步耦合分析需求,建立了传感器-万向节-焊枪钨极尖端三坐标系间的数学转换模型和熔池与焊枪钨极尖端运动坐标的双向耦合模型。通过预设机器人焊枪姿态摆动试验验证了双向耦合模型的有效性和准确性。在时空同一坐标下对比分析了不同焊接水平焊工对熔池状态的调控行为和焊缝成形质量的控制能力。结果表明,利用熔池-焊枪双向耦合模型可以获得能够表征焊工操控焊枪空间运动的较准确姿态样本数据;经模型转换的焊工操控焊枪α、β角与机器人摆动预定值的误差均小于1.2°,γ角误差约为1.5°;未经实操培训焊工操控焊枪规范性差,调控熔池动态平衡表现出调节时刻和规律的高随机性,对熔池状态动态评估能力极其匮乏,无法保证焊接过程稳定和高的焊接质量;经长期实训焊工运枪动作规范、规律性强,对熔池状态动态评估能力丰富和强的交互意识,全焊接过程能够保持熔池形态的稳定和焊缝的全熔透。     

Passive vision based seam tracking system for pulse-MAG welding

Welding robots have been widely used in manufacturing process to substitute for human welders. However, most of them are rigid and cannot adjust to variations in the weld seam positions caused by natural welding environmental factors. To address this problem, this paper presents a passive vision-based robotic welding system, which can realize the seam tracking function for pulse-MAG welding. In this paper, the light spectrum of the welding process is analyzed to determine the optical filters used during the image capture. Then, a robust image processing method is proposed to extract the offset from the image which contains much noise. The transformation formula is calibrated to obtain the relationship between the image coordinate system and the robot coordinate system. The tracking strategy is designed to improve the tracking precision and the stability of the welding process. Finally, experiments are conducted on straight line and curved line seam to verify the feasibility of the developed system.