Audio-visual modelling and control of GMA welding

本课题的研究方向为实验气体金属电弧（GMA）焊接过程识别与控制。目的是研究专业焊工在焊接时可以感知的视觉和声音信号之间的关系，以及他们在响应这些信号时采用的控制行动。进行这项研究的动机是，目前最先进的机器人GMA焊接系统仍然依赖于本质上的开环控制：参数设置预设为在恒定条件下给定接头几何形状的良好焊接质量的值。然而，专业的焊工不断调整焊枪的位置和速度，以及电压和送丝速度，以响应他们在焊接时所看到和听到的。这种人类反馈控制系统是通过经验学习的，在生产高质量焊缝方面非常有效。然而，弧焊是一项累人且危险的工作，涉及暴露于有毒烟雾，热量和强烈的紫外线辐射中，因此开发能够提供与人类焊工擅长的类似反馈控制的全自动/机器人焊接系统将大有裨益。这项研究的预期意义是更好地理解专业焊工在焊接时对他们接收到的声音和视觉线索的反应，以及如何将其应用于GMA焊接过程的自动控制。对社会的好处包括减少人类接触危险弧焊环境的可能性，同时保留对熟练焊接专业人员监督和编程机器人焊接操作的需求。

This research program is in the area of experimental gas metal arc (GMA) welding process identification and control. The objective is to investigate the relationships between visual and acoustic signals that expert human welders can sense when welding, and the control actions they employ in response to these.The motivation for pursuing this research is that the current state-of-the-art in robotic GMA welding systems still rely on what is essentially open-loop control: parameter settings are preset to values that should result in a good quality weld for a given joint geometry under constant conditions. However, expert human welders continually make adjustments to the welding torch position and speed, as well as to the voltage and wire feed-rate, in response to what they see and hear while they are welding. This human feedback control system is learned through experience, and is very effective at producing high quality welds. However, arc welding is a tiring and hazardous job involving exposure to noxious fumes, heat and intense ultra violet radiation, and it would therefore be of great benefit to develop fully automated / robotic welding systems capable of providing comparable feedback control that human welders excel at.The expected significance of this research is a better understanding of how professional welders react to the acoustic and visual cues they receive while welding, and how this can be applied to the automatic control of the GMA welding process. The benefits to society include the potential for reduced human exposure to the hazardous arc welding environment, while retaining the need for skilled welding professionals to oversee and program the robotic welding operations.