Research On Composite Fuzzy Control Method Of Spray-drying Process

The research content of this paper is put forward based on spray-drying process of dry powder. For a long time, the single PID control method is the main control method of dry powder spray-drying process, which has its advantages, but there are drawbacks. For example, a single control variable, long time of steady-state drying temperature and low capictiy to deal with interference and so on.In this paper, spray-drying process of dry powder is analyzed firstly to determine a new control method. Siemens 300 series PLC controller are used to establish the program. The cascade control method of the inlet temperature and exhaust temperature of double-loop of the heating steam is used to regulate the valve opening. Exhaust temperature is as the main controlled variable to regulate the steam valve opening coarsely; inlet air temperature is as the deputy variable to regulate the steam valve opening subtly, for fine-tuning of the steam valve opening. Main controller controller using composite fuzzy PID controller, and deputy controller using conventional PID control, Adjustment function is used in Composite fuzzy PID controller to adjust the the weight factors of the fuzzy logic controller and PID controller. Adjustment function parameters can be set by upper Siemens MP277 touch screen HMI software, which increases flexibility of the system to some extent. After determining this control method in this paper, on one hand, the Simulink control is used to make the simulation to compare the PID control method and composite fuzzy control method in the conventional case and in the case with the existence of different interference. On the other hand, Loop Simulation model based on the controller of Siemens 300 PLC is established as the main controller, and Wincc flexible 2007 software is for the upper upper screen configuration, connected via Ethernet communication mode, the application of effect of composite fuzzy PID control method and PID control method in the process of spray-drying is simulated and compared. Finally, the experimental data is analyzed.The results show that the spray-drying process using the double-loop cascade control method of the composite fuzzy PID controller as the main controller and PID controller as deputy controller both reflect a significant control advantage in software simulation or hardware emulation. Through the upper configuration software parameter setting, the flexibility of system control is increased. Meanwhile the advantages of artificial experiences are played, but also adapt to the majority of the production process in the nonlinear, time delay. It also has stronger anti-interference ability, shortens the time to reach steady state. This control method is proved to be successful.