Study On Quality Control Methods Based On Multi-sensor Information Fusion For Resistance Spot Welding

Resistance welding is a high efficient welding method and is an important branch of welding technology with a vital position and extensive application in many fields such as aerospace, automobile, electric appliance, etc. As the initial starting research on intelligent control for resistance welding is later, the quality control method is invariably the focus for the scholars in welding fields. At the present time, the quality prediction and evaluation and the control model established for spot welding process are based upon fuzzy technology and neural network method and so on. Whereas the research on this aspect is not satisfied because the complexity in spot welding and uncertainty in nugget forming process, especially the uniqueness of spot welding, which caused the quality control method for spot welding being a giant assignment.The development of quality control method for spot welding was analyzed in this paper and the reason for the unsatisfied quality control for spot welding was considered the less detecting parameters and the simple control method. Therefore a control method was researched in the action of welding current, electrode displacement, dynamic resistance, and a control method based upon multi-information fusion was also proposed in this paper. The weighted average algorithm was adopted to multi-sensor information fusion and the stuff, slab thickness, welding parameters were stored in the expert knowledge base for the calling in welding, so the more information of the weld nugget forming process in spot welding can be received in this way. The spot welding experiment indicated that the fluctuation of nugget size is 8%～22% controlled by constant current close loop control method and only 6%～12.5% controlled by multi-sensor information fusion control method in the circumstance of influencing factors such as shunt, electrode wear, loop inductive reactance, etc. The welding experimental results indicate that the multi-sensor information fusion control method can effectively compensate the influence caused by various factors, the welding quality stability can be ensured.