基于动态电阻理论的支持向量机点焊质量评估方法

Evaluation Method of Support Vector Machine Spot Welding Quality Based on Dynamic Resistance Theory

电阻点焊过程是一个具有高度非线性、有多变量耦合作用和偶然不确定因素的过程,且熔核形成过程时间极短,因此在工程应用中,大多采用破坏性试验检验焊接质量。针对这一问题,利用电阻点焊过程中动态电阻理论,建立了支持向量机预测模型,对点焊进行无损检测、质量评估。分析了电阻点焊过程、动态电阻的变化过程和熔核的形成过程,进而建立了支持向量机回归预测模型。利用该数学模型预测熔核直径的大小,评估焊接质量。利用焊接电流、焊接时间等主要焊接参数构造支持向量机样本数据,预测熔核直径。通过试验仿真证明,该模型能够较为准确地预测熔核直径。

Resistance spot welding process had the problems of highly nonlinear,multivariable coupling and occasional uncertainties,and the nugget formation process time was extremely short.Therefore,the destructive test was mostly used to check the welding quality in engineering applications.Aimed at this problem,the support vector machine prediction model was established based on the theory of dynamic resistance in resistance spot welding,which can be used for nondestructive testing and quality evaluation for spot welding.The change of dynamic resistance and nugget formation in resistance spot welding process were analyzed,and then the support vector machine regression prediction model was established,which was used to predict the diameter of nugget and evaluate the welding quality.The support vector machine was used to predict the nugget diameter based on the main welding parameters such as welding current and welding time and so on.The simulation results showed that the model can predict the nugget diameter accurately.