中文摘要：

高压超临界萃取控制参数具有时变、非线性的特点，对其进行精确控制具有很大难度。PID控制广泛应用于工业过程控制．但常规PID控制器参数对运行工况的适应性差。模糊控制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。将PID控制与模糊控制相结合，设计了模糊PID反馈控制器，形成了模糊PID复合控制方法。以软件代替硬件，利用某公司的S7—200 PLC编程语言STEP7编制了模糊PID控制程序，并结合组态王工控软件实现了高压超临界萃取装置的模糊PID控制。研究表明，模糊PID控制较小的超调量保证了超临界介质溶解度的稳定性，所建立的超临界萃取控制系统较强的抗干扰性、灵活性，保证了超临界苹取过程的稳定性和萃取效率。

英文摘要：

The accuracy control problem of high press supercritical extraction process with the time-variant and nonlinear controlling parameters is discussed, The PID control is widely used in industrial process control, but the compatibility of normal PID control method is not well. The fuzzy control is independent on mathematical model and possesses rapid regulating speed and good robustness, but its homeostatic accuracy is not excellent. , The fuzzy-PID controller is designed based on the PID control and fuzzy control methods, and the fuzzy-PID control method is proposed. The corresponding control program was developed by using S7-200 PLC language STEP7, and the fuzzy-PID control of high pressure supereritical fluid extraction equipment is realized based on the KingView process-control software. The results indicate that the solubility of the supercritical medium can be controlled stably by using the fuzzy-PID controller which possessing relatively strong capacity of resisting disturbance and flexibility, and the stability and efficiency of supereritical extraction process are improved.