基于变论域模糊PID算法的提高分子蒸馏五味子油质量和产量的真空度控制研究（英文）

Improvement of quality and yield of Schisandra oil by controlling vacuum degree during molecular distillation using variable universe fuzzy PID method

采用超临界萃取五味子粗油作为实验原料,在多级分布式分子蒸馏装置中进行五味子精油的提纯实验,对分子蒸馏实验的工艺参数与产品指标之间的关系进行了讨论,并以分子蒸馏的真空度控制作为研究对象,建立了分子蒸馏真空度的数学模型。由于分子蒸馏控制系统具有非线性、纯滞后、时变的特点,针对传统PID控制及模糊PID控制难以很好地满足控制要求的缺点,本研究提出了利用变论域模糊PID算法实现分子蒸馏真空度的定值控制,通过引入变论域的收缩和膨胀因子,对模糊阈值和PID控制器的参数进行了在线调整,对模糊控制器的量化因子和比例因子进行了动态调整,从而提高了控制精度。在Matlab环境下与PID控制方法进行了仿真对比,结果表明变论域模糊PID控制方法具有更好的稳定性和自适应能力,该控制方法可以有效提高五味子精油的质量和产量。

By supercritical fluid extraction Schisandra crude oil as raw materials for the experiment,the multistage distributed of Schisandra oil purification experiment was carried out in molecular distillation system.The relationship between processing parameters and product index of molecular distillation experiment were discussed,furtherly the vacuum degree mathematical model of molecular distillation was established.Because the molecular distillation control system had the characteristics of nonlinear,pure lag and time-varying,in view of the traditional PID control and fuzzy PID control,it was difficult to meet the control requirements.This study proposed the use of variable universe fuzzy PID algorithm to realize the molecular distillation vacuum fixed value control,by introducing a variable domain contraction and expansion factor.The parameters of PID controller and fuzzy threshold for online adjustment,the quantization factor and scaling factor fuzzy controller were carried on the dynamic adjustment,so as to improve the control precision.The results showed that the fuzzy PID control method had better stability and adaptability,and the control method can effectively improve the quality and yield of Schisandra essential oil.