Application of Predictive PI and Multiple Cascade Control in Ordering-cylinder

For the purpose of improving the stability of outlet temperature and the rapidness of temperature control system, a multi-cascade control scheme is designed based on the relationship between circulating wind and tobacco leaf temperature through the analysis of actual sampling values. The scheme adopts a three closed-loop strategy, the system model was identified by correlation analysis and the least square method, the inner and outer loop sub-controllers and the main controllers all use the predictive PI(Proportion Integration) controller. The simulation and practical application results show that comparing to the double cascade control, the multi-cascade control can effectively improve the response speed of the system, and the dynamic performance of the system. Among them, this scheme reduces the rise time by 40.4 % compared with the double-closed loop cascading system. The adverse effect of interference on the main circuit is further reduced by adding secondary circuit. Predictive PI algorithm may alleviate the large time delay of temperature control, and has good anti-interference and robustness. The overshoot after adding disturbance is only 86.3 % of the control system using fuzzy controller. This solution may provide support for accurately and stably controlling the outlet temperature of the ordering-cylinder.