Robust nonlinear control of GMAW systems-a higher order sliding mode approach

This paper presents the control of a gas metal arc welding (GMAW) system using one of the higher order sliding mode control algorithms, the super twisting controller, which is a continuous control and a superior control with its extreme robustness property. A nonlinear multi input multi output (MIMO) system model has been considered here for the design of the super-twisting controllers. The control inputs chosen are, the open circuit voltage and the wire feed speed which are used to control the current and arc length of the system. The performance analysis of the controllers are studied in the presence of wide variations of model parameter uncertainties. The simulation results are presented to illustrate the efficiency of the controller used.