不同参数下GMAW电信号关联维数分析

GMAW焊接过程的非线性决定了其混沌特性,关联维数是对动力系统混沌特性进行定量分析的主要指标.文中采用相空间重构方法,通过计算关联维数,对GMAW焊接过程中电流信号时间序列进行分析;并改变焊接电压、焊接电流、气体流量等工艺参数,研究不同参数下弧焊过程的混沌特性.结果表明,GMAW焊接过程的混沌现象,不仅存在于短路过渡当中,也存在于滴状过渡中.在此基础上,进一步研究了关联维数随焊接参数的变化规律,认为关联维数可作为焊接过程稳定性评价的依据,即关联维数越小,焊接过程越稳定,焊接工艺参数越优化.上述判据对焊接工艺参数选择的工艺优化试验,焊接过程稳定性监控提供了混沌判识的理论基础.

Correlation dimension analysis of current in GMAW welding

The nonlinearity in GMAW process determines its chaotic characteristics.Correlation dimension is a major quantitative analysis index in chaos researching of dynamical system.In this paper phase space reconstruction was used to analyse the current signal time sequence in GMAW by calculating correlation dimension.By changing welding voltage,welding current and gas flow rate,the chaotic characteristic of arc welding under different parameters was discussed.Studies show that chaos in GMAW welding process exists not only in short circuit transition,but also in droplet transition.On this basis,further study of the variation of correlation dimension under different parameters was put forward.Correlation dimension can be used as the basis for evaluating welding process stability.It means the smaller the correlation dimension is,the welding process is more stable and welding parameters are more appropriate.The criterion provides theoretical basis for the identification of chaos,which can be used in process optimization experiments for welding parameters selection and monitoring the stability of the welding process.