Abstract
Penetration control during welding is an important function of intelligent welding robot. Therefore the oscillation model of the molten pool was investigated to estimate and control the back bead width in TIG arc welding of thin steel plates. Recently, Yoo et al. proposed an analytical model of molten pool oscillation using the energy method. In their research, the molten pool is assumed to have a tapered cylindrical shape with elliptic free surfaces when it is in full penetration. The similarity ratio of top to bottom surface and thus, the back bead width are calculated using parameters including natural frequency, geometry of top surface, plate thickness and so on. Therefore, a welding penetration control system, in which the welding process is monitored via an arc sensor and a visual sensor, is constructed. The effectiveness of the system is demonstrated by automatic welding experiments of thin stainless steel plates.
