不锈钢点焊热过程的协同控制策略

Collaborative control strategy for stainless steel resistance spot welding process

着重探讨了协同控制法应用于不锈钢点焊过程控制的特殊性、必要性与适用性.针对动态电阻单调下降的不锈钢材料,以工艺试验确定的实际熔核形成起点,把焊接热过程明确划分为未形核与形成熔核两个阶段.进而,在这两个阶段中分别采用恒流控制和基于给定动态电流滞后角特性的模型化控制技术,即协同控制策略.结果表明,该监控策略能够保证不锈钢材料电阻点焊热过程的形核起点稳定,从而确保了阈值法控制的可靠性,焊接品质优良.

The particularity,necessity and suitability on the collaborative control method that was used to stainless steel resistance spot welding procers are discussed in this paper. Based on the experiment results,the welding process of every nugget was divided into two periods. That is,no-nugget period and nugget-growing period. In no-nugget period,the constant current control method was used. In nugget-growing period,the modeling control method was used based on the reference characteristics of the dynamic current lag angle. This control mechanism is the collaborative control strategy. The experiment results show that it can make the starting point of nugget stable,thus provide a threshold control method with high reliability and good nugget quality.