动态电阻点焊监控系统多参数分时段的监控算法

Multi-Parameter and Time-Section Control Algorithm Applying in Dynamic Resistance Controlled Spot Welding Monitored Control Systems

首次把动态电阻点焊自适应控制系统 (DRC)的控制模型分成不同时段用不同参数进行实时监控。即把动态特性曲线经过科学修正以后 ,在谷点时间到达阶段 ,根据谷点到达时间的提前或滞后 ,分别采用单输入单输出和双输入单输出模糊控制器进行控制 ;在谷点过后的上升阶段 ,采用比例积分控制算法 (PID)进行控制 ;考虑到电阻点焊生产过程中机械化和自动化程度非常高的特点 ,为了保证点焊形核质量和焊接时间的一致性 ,在动态特性曲线上升阶段后期 ,采用阈值前馈控制算法 ;同时 ,针对电阻点焊生产环境中网压波动频繁的特点 ,程序在进入焊接主程序之前 ,采用网压前馈控制算法。通过将前馈控制算法、模糊控制算法与已应用较成熟的PID控制算法相结合 。

The systematic control modeling of dynamic electric resistance controlled(DRC) spot welding was first divided into different period of time depending on different parameter for real time control in this paper.Namely,after modifying dynamic curve,in the period of valley point ,a single output fuzzy controller and a double output were applied respectively depending on advance or lag of valley point time.In the climbing period after valley point,the PID algorithm was applied for control.Considering highly mechanization and automation in spot welding process,a threshold feedforward algorithm was applied in anaphase of climbing period for certifying the consistency between nugget quality and welding time.Furthermore a network voltage feedforward automation was applied before the welding main program in accordance with the web voltage waving frequently.DRC control system became more credible in disturbing condition of spot welding by the mixture of feedforward control algorithm?fuzzy control algorithm and PID control algorithm.