封底焊道和焊道高度在窄间隙机器人焊接中的前馈控制

对于高质量的焊接而言,形成一个稳定的封底焊道和熔融金属板是很重要的。在窄间隙焊接中,使用常规焊接方法很难同时控制封底焊道和焊道高度,为了解决这个问题,可行的方法是焊枪沿着焊缝来回移动的回转焊接方法。在焊枪正向移动的过程中,电弧热量传递给根部锐边以获得一个宽阔的封底焊道。在焊枪反向移动的过程中,就逐渐形成了合适的焊道高度。因此,就为这种焊接类型建立了数学模型,计算出了最优行程长度,并通过焊接实验结果验证了其有效性。     

一类多目标焊缝跟踪优化模型和算法

针对焊缝跟踪过程中姿态的调整与规划问题,以移动焊接机器本体与焊枪为研究对象,在构建轮式移动焊接机器人的本体运动学模型基础上,考虑滑块滑长与焊枪长度等制约因素,以优化跟踪精度与速度为目标,建立了焊缝跟踪多目标优化模型。根据焊缝跟踪问题特征,设计了遗传算法,定义了编码结构,产生初始种群,构建了适应度函数。通过MATLAB进行仿真验证,并与BP神经网络进行对比,仿真结果表明该方法在加快焊缝跟踪速度、提高焊接精度方面的有效性。     

客车底盘骨架对接焊缝的视觉跟踪系统

根据客车底盘骨架对接焊缝的特点,设计了基于激光视觉传感的焊缝跟踪系统。针对图像处理运算量大的特点,为减少图像处理时间,提出了加窗处理算法。视觉传感系统采集并分析焊缝图像得出焊缝偏差,控制系统根据焊缝偏差指导机器人移动焊枪进行实时纠偏控制。实验结果表明,所设计的焊缝跟踪系统满足焊缝跟踪的精度要求,可以用于底盘骨架的焊接。     

焊缝位姿及焊枪位姿的模型

针对机器人弧焊条件下的特殊要求,建立了焊缝位姿和焊枪位姿模型,以坐标系的形式定量描述焊缝及焊枪的位置和方向,确定了能够准确且严格地描述焊缝的焊接位置和焊枪姿态的参数：焊缝倾角、焊缝转角及焊枪工作角和行走角,并给出了计算方法。上述参数不但计算简便,而且可以直接代表焊接位置和焊枪姿态对焊接质量的影响因素。模型对于焊接工艺的建模与仿真以及机器人焊接的建模与离线编程具有非常重要的意义。     

弧焊机器人焊枪姿态的简便示教

弧焊机器人焊接空间搭接焊缝时,对于焊枪姿态的示教往往占据了大量的示教时间。为此,提出一种焊枪姿态的简便示教方法。该方法采用根据几何约束计算焊接时焊枪姿态的思路完成焊枪姿态的示教。先以任意焊枪姿态对焊缝进行位置示教,然后根据焊缝的切向矢量和焊接工艺要求的焊枪角度计算出焊接时的焊枪姿态。对于三维曲线焊缝,只有当局部焊接平面与基坐标系的Oyz平面不垂直时,需要进行简单的焊枪姿态示教,示教时只须调整机器人绕工具坐标系一个轴转动的角度即可完成。使用该方法可以显著地减少示教难度和示教时间,提高姿态示教的精度。详细介绍焊枪姿态的描述方法、焊接方向角的计算方法和焊枪姿态的调整方法等关键技术。使用搭接曲线焊缝进行试验验证,证明了该方法的可行性。     

焊接机器人在铝制板翅式散热器主焊缝焊接中的运用

介绍了焊接机器人在铝制板翅式散热器主焊缝焊接中的运用,通过优化焊接机器人焊接工艺,采用单层焊接替代手工TIG双层焊接,其单层焊熔深可达到4.0 mm~4.5 mm,单层焊时焊枪的焊速可达到350 mm/min~500mm/min,其焊缝爆破与压力交变强度满足铝制板翅式散热器主焊缝强度要求,焊缝外观成型良好,效率高,质量稳定可靠,同时也降低了工人的劳动强度。     

微波GaAs 功率芯片AuSn 共晶焊接微观组织结构研究

文中采用Au80Sn20共晶焊料对GaAs功率芯片与MoCu基板进行焊接,分析了焊接温度、摩擦次数等工艺参数对共晶焊接的影响,给出了GaAs芯片共晶焊的工艺参数控制要求,通过扫描电镜及能谱仪分析接头的显微组织、元素分布,通过X射线检测仪测定接头的孔洞率,研究GaAs芯片背面和MoCu基板表面的镀层与焊料之间的相互作用以及焊缝的凝固过程.GaAs芯片背面的Au层部分溶解在AuSn焊料中,MoCu基板表面的Au层完全溶解在AuSn焊料中,焊缝与Ni层结合,焊缝由靠近两侧母材的ξ-Au5Sn金属间化合物层和中间的Au-Sn共晶组织组成.     

基于视觉传感的机器人焊缝纠偏控制系统

针对工业机器人多层多道焊缝纠偏问题,提出一种基于视觉传感的人机互动机器人焊缝纠偏方法,并建立相应的视觉传感焊缝纠偏控制系统。该系统主要包含视觉传感采集及标定和机器人焊缝纠偏控制两个子系统。将工业相机安置在焊枪上得到拍摄的实时焊接图像,然后利用Windows Forms开发的焊接监控软件,工作人员通过观察监控界面,能够对焊枪偏离焊缝是否超过允许范围做出判断,再通过控制面板发出纠偏指令传送至可编程逻辑控制器(Programmable logic controller,PLC),PLC向机器人控制器发出控制信号,机器人调用"机器人传感器接口"(Robot sensor interface,RSI)的信息流,将PLC控制信号转化为机器人末端偏移量并执行,使焊枪调整至合适位置,达到焊缝纠偏控制目标。在验证试验过程中,该系统反应较灵敏,焊缝纠偏准确度较高,整个过程运行平稳,焊缝成形质量良好。     

基于S7-200 SMART PLC的自动焊接系统设计

为提高中厚壁长直焊缝焊接效率和精度,设计了以西门子S7-200 SMART PLC为控制核心,以焊枪运行机构和手工焊机为执行机构的多层自动焊接系统。通过控制具有三自由度的焊枪运行机构实现焊枪按设定轨迹的多层运行,通过控制手工焊机实现对焊接电流、焊丝及保护气等的全部时序控制。文章从系统总体结构、系统硬件及软件等方面详细阐述了设计思路和实现方法。重点介绍了利用单台S7-200 SMART PLC实现对三台步进电机的定位和速度控制。本系统已投入使用,效果良好。     

关于机器人焊接路径规划优化的研究

焊枪与焊缝相对位置关系以及机器人运动平稳性直接决定焊缝质量,论文采用变位机调整焊枪与焊缝相对位置,并且通过建立机器人运动平稳性函数优化机器人运动平稳性,综合焊接位置,机器人位置建立综合目标优化函数进行焊接路径的优化。采集的数据显示在焊枪与焊缝在最优位置附近的情况下,机器人运动平稳性有着显著提高。结果表明,基于粒子群算法对焊接路径进行优化操作能够提高机器人加工过程的平稳性,可以提高焊缝质量。     

碳极氩气拘束电弧碳化钨颗粒复合材料堆焊工艺研究

从降低硬质合金的烧损和沉淀出发研制了碳极氩气拘束电弧焊炬用以WC颗粒堆焊,结果表明所设计的焊炬堆焊WC颗粒可明显降低硬质合金颗粒的烧损和沉淀。     

Autonomous seam acquisition and tracking system for multi-pass welding based on vision sensor

Automatic welding technology is a solution to increase welding productivity and improve welding quality, especially in thick plate welding. In order to obtain high-quality multi-pass welds, it is necessary to maintain a stable welding bead in each pass. In the multi-pass welding, it is difficult to obtain a stable weld bead by using a traditional teaching and playback arc welding robot. To overcome these traditional limitations, an automatic welding tracking system of arc welding robot is proposed for multi-pass welding. The developed system includes an image acquisition module, an image processing module, a tracking control unit, and their software interfaces. The vision sensor, which includes a CCD camera, is mounted on the welding torch. In order to minimize the inevitable misalignment between the center line of welding seam and the welding torch for each welding pass, a robust algorithm of welding image processing is proposed, which was proved to be suitable for the root pass, filling passes, and the cap passes. In order to accurately track the welding seam, a Fuzzy-P controller is designed to control the arc welding robot to adjust the torch. The Microsoft Visual C++6.0 software is used to develop the application programs and user interface. The welding experiments are carried out to verify the validity of the multi-pass welding tracking system.     

A control system for uniform bead in fillet arc welding on tack welds

Positioning a workpiece accurately and preventing weld distortion, tack welding is often adopted before main welding in the construction of welded structures. However, this tack weld deteriorates the final weld bead profile, so that the grinding process is usually performed for a uniform weld bead profile. In this study, a control system for uniform weld bead is proposed for the fillet arc welding on tack welds. The system consists of GMA welding machine, torch manipulator, laser vision sensor for measuring the tack weld size and the database for optimal welding conditions. Experiments have been performed for constructing the database and for evaluating the control capability of the system. It has been shown that the system has the capability to smooth the bead at the high level of quality.     

火车钩舌CO_2/MAG自动焊机的研制及应用

针对车钩钩舌面补焊工艺要求,研制出一种专用于火车车钩钩舌CO2/MAG自动堆焊机,克服了传统的手工堆焊工效低、劳动强度大且耗材等缺点。该焊机以PLC为核心的控制系统控制电机和焊枪的三维移动,经过工厂运行表明：该系统运行可靠,实用性强。     

基于DMC-1842运动控制卡的焊枪运动控制系统

在分析了焊枪运动装置的运动特点后,提出了一种新型焊枪控制方案。通过对焊枪往复运动、上下移动的深入分析,阐明了焊枪运动的要求,为新型焊枪控制方案的设计提供了依据。     

Modeling of multiple characteristics of an arc weld joint

Process parameters modeling have always been one of the key aspects in development of an adaptive control of arc welding process. The welding process parameters are inherently nonlinear, time-delayed, and interdependent, and their on-time adjustment highly influences a sound weld bead formation and process monitoring. During the welding process, parameters control is the primary goal to leads a quality welding. Moreover, the final weld joint behavior, i.e., residual stress, welding strength, and micro-crack formation are generally observed after cooling of the weld product. Thus, it has always been a difficult task to control mechanical properties of a final weld joint. To obtain the best mechanical properties, the final weld joint characteristics needed to be controlled and predicted during the process itself by precise adjustment of the process parameters. The paper presents a neuro-fuzzy modeling approach to provide adaptive control for the automatic process parameter adjustment. Three input parameters wire feed speed, welding gap, and torch speed are modeled with welding current output, providing control over weld bead formation during the welding. The same input process parameters are also modeled to predict final weld joint characteristics, i.e., dilution ratio, hardness of weld bead, hardness of fused zone, and bead width. In order to ascertain the effectiveness of the neuro-fuzzy modeling approach, multiple regression models were also developed to compare the performances.     

Accelerometer-based position and speed sensing for manual pipe welding process

For manual pipe welding process, welding position and speed are two of the most important welding parameters. Highly skilled pipe welders can well adjust their operation to produce high-quality welds. However, even experienced welders may sometimes have defected welds due to improper welding speed. The weld quality will be better guaranteed if the welding position and speed can be measured and other welding parameters can be changed accordingly. This paper introduced the development and experiment results on a practical accelerometer-based torch sensor to measure torch position and speed. Based on the measured acceleration data, the two important welding parameters were calculated with moderate computing load by an embedded control system. For future work, the welding position and speed calculation with sufficient accuracy can help the design of advanced control algorithm to various pipe welding processes.     

An application of genetic algorithm for edge detection of molten pool in fixed pipe welding

This paper presents a study on an application of genetic algorithm (GA) for edge detection of molten pool in fixed pipe welding. As circumferential butt-welded pipes are frequently used in power stations, offshore structures, and process industries, it is important to investigate the characteristic of the welding process. In pipe welding using constant arc current and welding speed, the bead width becomes wider as the circumferential welding of small-diameter pipes progresses. In order to avoid the errors and to maintain the uniform weld bead over the entire circumference of the pipe, the welding conditions should be controlled as the welding proceeds. This research studies the intelligent welding process of aluminum alloy pipe 6063S-T5 in fixed position using the AC welding machine. The monitoring system used an omnidirectional camera to monitor backside image of molten pool. A method of optimization for image processing algorithm using GA was proposed and has been implemented into a process to recognize the edge of molten pool. The result of detection, which is back bead width, was delivered into a fuzzy inference system to control welding speed. The experimental results show the effectiveness of the control system that is confirmed by a sound weld of the experimental results.     

弧焊机器人焊炬姿态规划系统的研究

为提高弧焊机器人的适应性和自动规划功能，研究了一种空间全位置焊接条件下的焊炬姿态自动规划系统。该系统借助于相应的摄像机标定软件，计算测试软件和焊炬姿态规划软件，协调计算机视觉，信号采集，图像处理等模块检测焊缝的空间信息，然4后查询焊炬姿态优化数据库，运行离线偏程等离子模块，实现自动规划弧焊机器人的焊炬姿态，采用研制的爆炬姿态规划系统在空间全位置条件下进行焊接实验，结果表明，该系统能保证爆接中焊缝的成形良好。