Modeling and control of quasi-keyhole arc welding process

Quasi-keyhole is a novel approach proposed to operate the keyhole arc welding process. Because the method's effectiveness depends on the amperage of the peak current used to establish the keyhole, this paper proposes adjusting the amperage based on the duration of the peak current, which equals the keyhole establishment time. A nominal model structure has been selected from those identified using experimental data and been used in the design of an adaptive predictive control system. Closed-loop control experiments have been conducted to verify the effectiveness of the developed system under varying set-points and varying travel speeds. (C) 2003 Elsevier Science Ltd. All rights reserved.