多重控制策略在烟叶复烤过程中的应用研究

The Application of Multiple Control Strategy to Tobacco Re-drying Process

针对在烟叶复烤的生产过程中,存在出口含水率控制精度不足和因调节阀达到饱和而失去调节作用的问题,设计一种可以控制多个操纵变量的三重控制方案.由于回潮室高压泵频率调节对出口水分的影响最快速、最直接,故作为主控制器的控制对象,主要采用预测PI(proportional-integral)控制算法.由于混合水调节主要影响整个回潮室的湿度场,调节相对缓慢,故作为副控制器1控制对象,主要采用PI控制算法.为了防止高压泵开度和混合水调节阀达到饱和,副控制器2以冷房含水率设定值为控制对象,间接影响出口水分含量.实际运行结果表明,该控制算法能够精确控制出口含水率精度,并及时协调各调节阀的开度.这为工业生产提供了新的控制思路,提高了整个生产线的自动化程度,具有很大的工业应用价值.

In the tobacco re-drying process,there is a problem in which the control of the outlet moisture content has poor accuracy and the regulating valve does not regulate effectively due to being saturated. We design a triplex control strategy that can control multiple variables. Because the regulation of the high pressure water pump in the resurgence section has a direct and rapid effect on the outlet moisture,we employ the predictive proportional-integral（ PI） control algorithm to the control object of the main controller. Because the regulation of the mixed water slowly changes the humidity in the resurgence section,we employ the PI control algorithm to the first subsidiary controller of the main controller. In order to prevent openness in the high pressure pump and the saturation of the mixed-water regulating valve,we chose a set value of the moisture content in the cooling section as the second subsidiary controlled object to indirectly influence the outlet moisture content. The actual operation results show that the proposed control algorithm can precisely control the outlet moisture content and promptly coordinate the degree of openness of the regulating valve. This strategy provides a new control method for industrial production,improves the automation level of the production line,and will prove to be greatly beneficial in industrial applications.