Stability Control of Weld Formation in Variable Polarity Plasma Arc Welding

变极性等离子弧焊焊缝成型的稳定性控制

• 批准号: 9900011
• 负责人: Radovan Kovacevic
• 金额: $ 23.99万
• 依托单位: Southern Methodist University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-05-01 至 2004-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9900011&HistoricalAwards=false
• 关键词: Stability; Control; Weld; Formation; Variable

This project will investigate a novel approach in regulating the heat and arc force applied to the workpiece as a basis for closed-loop control of the keyhole stability in variable polarity plasma arc welding. A machine vision system will be used to capture clear keyhole images from the front side of a workpiece and correlate these images with the dynamics of weld formation. A closed-loop control system based on a neural network model that relates the keyhole size with control variables such as wire feeding speed and welding current was established and tested. Variable polarity plasma arc welding is an ideal arc welding process for aluminum alloys. It features gas pore-free, full-penetration weld in a single pass of thick sections ranging from 3 mm to 25 mm, and relatively low cost. Currently, the stability of weld formation is still dependent on open-loop control. The critical features of this process can be lost due to the existence of unexpected interference. This is unacceptable for the fabrication of key products where welding accuracy must be achieved in the first trail. The project is expected to advance the plasma arc welding technology and result in significant impact on the production of high-quality key aluminum alloy products in the defense, avioanics, automobile, and shipbuilding industries.

该项目将研究一种调节施加到工件上的热量和电弧力的新方法，作为变极性等离子弧焊中小孔稳定性闭环控制的基础。 机器视觉系统将用于从工件正面捕获清晰的小孔图像，并将这些图像与焊缝形成的动态相关联。 建立并测试了基于神经网络模型的闭环控制系统，该系统将小孔尺寸与送丝速度和焊接电流等控制变量相关联。变极性等离子弧焊是一种理想的铝合金电弧焊工艺。 其特点是可在3mm至25mm厚截面的单道焊缝中实现无气孔、全焊透焊接，且成本相对较低。 目前，焊缝成形的稳定性仍然依赖于开环控制。 由于意外干扰的存在，该过程的关键特征可能会丢失。 对于必须在第一次试验中就达到焊接精度的关键产品的制造来说，这是不可接受的。 该项目预计将推进等离子弧焊技术的进步，对国防、航空、汽车、造船等行业高质量关键铝合金产品的生产产生重大影响。