镁合金薄板TIG焊自适应弧长控制

Adaptive arc length control for magnesium alloy sheets TIG welding

在研究镁合金薄板TIG焊过程弧压-电流-弧长关系的基础上,提出了一种基于弧压、电流与弧长间的关系模型来准确控制弧长的技术。同时,结合PID和Fuzzy控制的原理,设计了一种自适应ALC(Automaticlengthcontrol)控制器,克服了常规AVC(Automaticvoltagecontrol)系统的局限,有效地解决了镁合金薄板TIG焊过程中的弧长控制问题。焊接试验表明,该系统能自适应工件表面的变化实现弧长的自动跟踪,在电流变化的收弧及引弧期间也实现了较好的弧长控制,且动态精度高、稳定性好。

Based on the investigation of the relationship among the current, arc voltage and arc length in magnesium alloy sheets TIG welding, a new model based on the relationship among the current, arc voltage and arc length had been put forward which was used to control arc length exactly. At the same time, it combined the principle of PID and Fuzzy to design a kind of adaptive ALC (automatic length control) control system. The developed system not only overcame the limitation of traditional AVC (automatic voltage control) controlled system, but also resolved the problem of arc length control for the magnesium alloy TIG welding. The test results show that arc length could be traced and controlled according to the change of workpiece surface, and it also realizes arc length control well during welding initiation and termination with remarkably current change, moreover it has high dynamic response accuracy and good operation reliability.