Application of MIMO direct adaptive control to gas metal arc welding

This paper presents the design of a direct model reference adaptive control (DMRAC) for a gas metal arc welding process (GMAW). Recently developed highly nonlinear fifth order mathematical model for the GMAW process is used. Simplifications and linearization yield the process to be modeled as two-input two-output second order system. Current and arc voltage as being the process outputs are controlled by open circuit voltage and wire feed speed, which are chosen as the process control inputs. Considering wide range of operating conditions, process parameters are allowed to vary within their prescribed ranges. Simulations are performed on the fifth order nonlinear process and satisfactory results are obtained.