基于模糊自适应的电阻点焊恒流控制

Study on Constant Current Control of Resistance Spot Welding Based on Fuzzy Adaptive

针对中频直流电阻点焊在连续焊接过程中出现的电极磨损和焊接有效接触面积变化情况,导致焊接电流不稳定、焊核出现飞溅和虚焊问题,利用智能算法设计了一种模糊自适应控制方案.该方案利用负载电阻变化率和瞬时最大焊接功率作为输入量,使用模糊控制算法根据电极直径和焊点有效接触面积变化情况,确定补偿电流大小,实现焊接电流恒定输出.结果表明:该方案比传统PID控制具有更好的控制性能,实现了连续焊接下的精准恒流控制.

In the continuous welding process of medium frequency DC resistance spot welding,the electrode wear and the change of welding effective contact area lead to the instability of welding current,spatter and false welding of nugget.A fuzzy adaptive control scheme is designed by using intelligent algorithm.In this control scheme,the dynamic resistance change rate and instantaneous maximum welding power are used as inputs,and the fuzzy control algorithm is used to determine the compensation current according to the change of electrode diameter and effective contact area of solder joint,so as to realize the constant output of welding current.Simulink software simulation results show that the scheme has better control performance than that of the traditional PID control,and realizes the precise constant current control under continuous welding.