Fuzzy Controller of Resistance Spot Welding Based on DSP

The structure and designing idea of resistance spot welding fuzzy controller based on DSP are presented in this paper.The high speed of the DSP was used and point by point integration method was adopted to calculate RMS(Root Mean Sguare) of current.The input of the system is the deviation and deviation rate between RMS of the current and setting current.The output is the pilot angle of SCR(Silicon Controlled Rectifier).Through the fuzzy method,it can maintain welding current at the invariable level finally.The results of the experiments show that the controller has good compensation function when input voltage and circuit resistance are changing.The accuracy of constant-current control system is lower than 2 percent,and can satisfy engineering requirement.