基于S7-200的超临界萃取参数的模糊PID控制

Fuzzy-PID Control of Supercritical Extraction Based on S7-200

PID控制是最早发展起来的控制策略之一,由于其算法简单、可靠性高,被广泛应用于工业过程控制。在实际生产现场中,常规PID控制器参数对运行工况的适应性差。模糊控制与PID控制相比具有不依赖系统数学模型、调节速度快、鲁棒性好等优点,但稳态精度欠佳是模糊控制的一个弱点。将这两种控制策略结合起来,取长补短,形成了模糊PID复合控制方法。本文以软代硬,利用西门子公司的S7-200来实现超临界CO2萃取过程的模糊PID控制,提高了萃取过程的稳定性和萃取精度。

PID control is one of early control methods,because of its simple arithmetic , and hingh reliability,it is widely used in the process of industrial control.However,in the real application normal PID control parameters usually can not adapt the industrial condi- tion.By comparison,Fuzzy control has many advantages,such as high robustness,quick response,and independent of mathmctic models. But,Fuzzy control also has the disadvantage of low steady precision.This paper combinated the two methods,formed Fuzzy-PID control,and used S7-200 to control the process of supercritical extraction.Using the composite method,the stability and precision of the process of extraction largely improved.