脉冲GTAW焊过程辩识及PID控制

Identification of welding process and PID control in pulsed gas tungsten arc welding

针对脉冲ＧＴＡＷ焊熔池动态过程，利用面积法、Ｌａｐｌａｃｅ变换的极限定理法及最小二乘法对焊接速度与熔池背面熔宽模型进行了辩识。结果表明，面积法更适用于熔池动态过程辩识；对辨识所得到的二阶熔池模型进行了 ＰＩＤ控制器设计，并针对起焊时的时滞采用 Ｓｍｉｔｈ预估器予以补偿。实验结果表明，Ｓｍｉｔｈ预估器对时滞具有很好的补偿效果。

The welding pool model of dynamic process in pulsed gas tungsten arc is identified by three methods: the area method, Laplace-transformation limit theorem method and least square method. The input of the model is welding speed and the output is backside head width of welding pool. The identification effect of the area method is the best among the three methods. The PID control law is designed for the two-order welding pool model obtained by identification and the Smith predictor is adopted to compensate time-delay at starting-welding. Test shows that the Smith predictor can compensate time-delay well.