变坡口窄间隙摇动电弧脉冲焊接方法及适应控制

This project proposes a novel process of swing arc narrow gap pulsed welding for variable groove. A mechanism of micro-bent conductive rod, driven by hollow-axis stepping motor, is designed to weave the arc circularly. To control in real time arc swing, torch position and deposited metal volume, this system detects the position and gap value of narrow welding groove by a composite manner of infrared passive visual sensing and swing arc sensing, thus adapting the swing arc to a varying groove automatically. This adaptive control, together with the synergetic control effects of arc swing with pulsed arc current, will contribute to the enough heat input into groove sidewalls, and finally to the even and steady height and sidewall penetration of weld. This research will be focused on the control methods of sidewall penetration, arc swing and deposited metal volume, and the control algorithm and the visual and arc sensing detection techniques of seam tracking. In addition, it will reveal the characteristics and their mathematical expressions of arc heat production and arc force, investigate the effects of arc swing process parameters on the metal transfer behavior, molten metal flow, weld formation and the microstructure and properties of joint, and analyze the effectiveness and realtime performance for the adaptive control of the swing arc welding process. The above work will help to establish the theoretical fundamentals of narrow gap swing arc GMA welding for variable groove, and to promote the developments of high-efficiency and intelligent welding theory and technology.

本项目提出一种变坡口窄间隙摇动电弧脉冲焊接方法，通过红外被动视觉与摇动电弧复合传感方式检测焊接坡口位置和间隙大小，实时控制电弧摇动、焊炬位置以及焊接熔敷量，使空心轴电机驱动的微弯导电杆式摇动电弧能自动适应坡口环境变化，并运用电弧摇动与脉冲焊接电流的协同控制效应，让坡口两侧壁获得足够热输入，以形成均匀稳定的焊缝高度和侧壁熔深。着重研究坡口侧壁熔深控制方法、电弧摇动和焊接熔敷量的适应控制方法、焊缝跟踪的红外视觉与摇动电弧复合传感检测方法及控制算法，研究摇动电弧产热特性和电弧力分布规律并进行数学表征，研究电弧摇动工艺参数对熔滴过渡行为、熔池流动特性、焊缝凝固成形、接头组织性能的影响规律，分析摇动电弧焊接适应控制的实时性和有效性，建立变坡口摇动电弧窄间隙GMA焊接的理论基础，促进高效及智能化焊接理论与技术的发展。

本项目提出了一种变坡口窄间隙摇动电弧脉冲焊接方法及系统，通过电弧摇动与脉冲焊接电流的协同作用，实现了对坡口侧壁熔深的有效控制；通过红外被动视觉与摇动电弧复合传感，实时检测焊接坡口位置和间隙大小，实现了对电弧摇动、焊炬位置以及焊接熔敷量的适应控制。研究了坡口侧壁熔深控制方法、焊缝跟踪传感检测方法及控制算法、电弧摇动和焊接熔敷量的适应控制方法，揭示了摇动电弧能量特性、电弧力学特性、熔滴过渡行为、熔池流动特性、焊缝凝固成形规律，分析了摇动电弧焊接适应控制的有效性，从而建立了变坡口摇动电弧窄间隙GMA焊接的理论基础，丰富了高效及智能化焊接理论及技术。 . 研究结果表明，摇动电弧有效调节了脉冲电弧热和电弧力在窄间隙坡口内的分布，使坡口侧壁获得了足够热输入，形成了稳定的侧壁熔深；导电杆折弯角度影响前向电弧力分量，电弧线能量比影响电弧在摇动和侧壁停留期间的能量分布，电弧力冲量比和电弧摇动影响熔池流场，从而决定立向上焊接熔池下淌程度；通过红外被动视觉传感和摇动电弧传感，能分别以约±0.1mm和±0.25mm的检测精度对焊缝偏差和坡口宽度进行快速可靠检测，并能在焊接过程强干扰和变坡口条件下，有效实现了焊缝跟踪控制（控制精度约±0.25mm）、以及电弧摇动角度（控制精度约为±1.5°）和焊接熔敷量（焊接速度控制精度约为±5mm/min）的适应控制，获得了均匀的焊缝成形。因此，采用变坡口窄间隙摇动电弧焊接方法，可以实现高效高质量窄间隙GMA焊接。