Adaptive Control of Weld Penetration by Detecting Oscillation and Shape of the Weld Molten Pool

在这一年里，构建了薄板对接焊焊缝熔深识别和控制的鲁棒控制系统。在该系统中，实现了熔池形状的识别和熔池振荡佩库里尔频率的检测。此外，为了在坡口形状、坡口间隙等焊接条件变化的情况下获得良好的焊接效果，建立了焊接过程中焊接现象的诊断和焊接工艺控制系统。取得的主要成果如下：(1)构建了一种带有视觉传感器的智能焊接机器人系统，该系统能够监测焊接熔池的长度、宽度和面积等形状和尺寸。(2)通过控制焊接熔池的尺寸，构建了一种自适应控制系统。(3)提出了一种基于人工神经网络的自适应控制系统。其输入层由长度、宽度、面积、焊接速度、焊接电流和焊线根部间隙6个单元组成，输出层由7个单元组成，隐层由8个单元组成。(4)采用脉冲电流作为焊接电流，检测基流时间内的弧压振荡，检测熔池振荡的频率。(5)建立了熔池频率检测原理的熔透焊控制系统。(6)进行了低碳钢TIG弧焊试验。验证了所构建的焊接控制系统的有效性。

In this year, a robust control system for recognizing and controlling the penetration of the weld in butt welding of thin steel plates was constructed. In this system, the recognition of the molten pool shape and detection of peculier frequency of molten pool oscillation were performed. Furthermore, in order to obtain sound weld regardless change of welding conditions, such as groove shape, gap of groove and so on, system to diagnose the welding phenomena during welding and to control welding conditions were constructed.Main results obtained are summarized as follows.(1) An intelligent welding robot system with vision sensors that observe the shape and dimensions of the weld molten pool, including length, width and area was constructed.(2) An adaptive control system to optimumly control the penetration of weld by controlling the dimensions of the weld molten pool was constructed.(3) An adaptive control system using Artificial Neural Network was proposed. lt has an input layer of six units for length, width, area, welding speed, welding current and root gap of welding line, an output layer of seven units that indicates change of welding current, and an hidden layer of eight units.(4) Applying pulse current as welding current and detecting oscillation of arc voltage during base current time, the frequency of the oscillation of molten pool can be detected.(5) A system to control penetration welding using the principle to detect the peculiar frequency of molten pool was constructed.(6) Mild steel plate welding experiments using TIG arc welding method were performed. The effectiveness of the constructed welding control systems was confirmed.