短路过渡电弧焊电流信号的近似熵分析

依据近似熵的理论和算法，从非线性角度对纯CO₂保护气体条件下短路过渡电弧焊的电流信号进行了近似熵分析.通过对不同的送丝速度、给定电压及气体流量下电流信号的近似熵计算和比较，表明近似熵可以作为短路过渡稳定性的评判标准.近似熵越大，波动越小，焊接过程就越稳定. 关键词： 非线性 近似熵 短路过渡 稳定性     

Dini定理在级数判敛中的应用

Dini定理在判断函数序列或函数级数一致收敛性中有多种应用。     

确定延迟时间互信息法的一种算法

介绍了相空间重构中确定重构延迟时间的互信息法理论及其具体的计算方法.针对互信息法应用中计算复杂、程序难以编写问题,提出了一种基于网格层数的简便实用程序算法.对网格层数参数进行了结果分析,表明在利用互信息法确定重构延迟时间时,只需要计算到某一个网格层数即可,不需要计算出精确的互信息值,简化了计算的复杂程度.最后通过对Lorenz和Rossler两个吸引子的Lyapunov指数计算,证实了该算法的合理性.     

Approximate entropy a new statistic to quantify arc and welding process stability in short-circuiting gas metal arc welding

Based on the phase state reconstruction of welding current in short-circuiting gas metal arc welding using carbon dioxide as shielding gas, the approximate entropy of welding current as well as its standard deviation has been calculated and analysed to investigate their relation with the stability of electric arc and welding process. The extensive experimental and calculated results show that the approximate entropy of welding current is significantly and positively correlated with arc and welding process stability, whereas its standard deviation is correlated with them negatively. A larger approximate entropy and a smaller standard deviation imply a more stable arc and welding process, and vice versa. As a result, the approximate entropy of welding current promises well in assessing and quantifying the stability of electric arc and welding process in short-circuiting gas metal arc welding.