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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 the earliest developed control strategies. Due to its simple algorithm and high reliability, PID control is widely used in industrial process control. In the actual production site, the conventional PID controller parameters poor adaptability to operating conditions. Compared with PID control, fuzzy control has the advantages of independent system mathematical model, fast regulation, good robustness and so on. However, the poor steady-state accuracy is a weakness of fuzzy control. Combining these two kinds of control strategy, make up for each other’s weakness, formed a fuzzy PID compound control method. In this paper, the soft-hard, the use of Siemens S7-200 to achieve supercritical CO2 extraction process of fuzzy PID control to improve the extraction process stability and extraction accuracy.