Model reference adaptive control scheme for enhancing bead width and depth of penetration during cold metal transfer process

Abstract

This paper presents an adaptive welding control scheme for the Cold Metal Transfer process (CMT) deployed for joining Aluminium 6061 alloy sheets. The mathematical model of the CMT welding control system is derived and the plant model is estimated using system identification technique. A Model Reference Adaptive Controller (MRAC) is designed to maintain the desired welding current during the occurrence of electrode wire short circuiting and melting during the joining process. The proposed adaptive control method is compared with that of the conventional PID controller for the performance analysis. The simulation results indicate that the designed MRAC for CMT process successfully maintained the welding current at the set point when subjected to short circuit and arcing phases whereas the conventional PID controller is unable to retrieve the welding current at set point. The experimental validation using the designed MRAC is carried out in the CMT welding set up. The experimental results agree with the simulation results and emphasizes that the MRAC improves the welding performance by yielding good weld joints at requisite time and quality.