A Proportional-Integral Controller for Resistance Spot Welding Using Nugget Expansion

Abstract

An electrode wear has been found to cause considerable quality variation in the process of resistance spot welding. This paper presents a study on the electrode wear growth and develops a microprocessor-based feedback controller that can compensate weld quality variation due to electrode deterioration. The controller developed in this study utilizes a PI control algorithm, incorporating the electrode movement as a feedback signal. A series of experiments was performed to clarify the wear growth phenomenon and to evaluate the performance of the controller. The experimental results show that the electrode wear can significantly cause quality deterioration, but this can be effectively compensated via application of this proposed control technique.