Research Of Intelligent Control System For Continuous Microwave Dryer

China is a large agricultural production and consuming country. If the harvest can not be dehydration on time, it will lead to decay, deterioration, which makes the harvest decline in quality and not conducive to the storage and consumption. At present, the technology of microwave drying has been widely used in the dehydration of grain and agricultural products processing. However, so far, the device of microwave drying is low degree of automation, operation is not convenient and it relies on the experience of the staff, which results in inefficient drying and drying quality difficult to guarantee. Therefore, the paper aims to develop an intelligent control system for microwave continuous drying machine with high degree of automation, high precision of control, low-cost and so on.This article describes the research status of drying control system in recent years, analyses the control problems of existing microwave continuous dryer, and proposes the design plan of microwave continuous dryer control system. The design of the control system includes hardware and software, the control system consists the bit machine and the host computer. Lower position machine uses single-chip and analyses to select the temperature, humidity, moisture sensors, and other major components, used to complete the data acquisition of the drying cavity temperature and humidity as well as import and export material data collection,data processing, sending and control tasks. The host computer using a PC, mainly completes the setting parameters of the cavity, data processing, analysis, storage and display. The software is written by Keil C, using the Lab VIEW software to make the user interface of the host computer. Upper and lower machine communication system uses RS-485serial port. Taking into account in microwave continuous drying presences nonlinear, time-varying, large time delaying, and the strong coupling between the parameters, which makes the whole drying process difficult to establish a precise mathematical model, however, the conventional control methods are difficult to achieve the desired control, in order to improve the control accuracy, the fuzzy control strategy is applied to the control system of the microwave dryer, realizing the parameters (temperature and humidity) of the drying process and the parameters individually precise control. Using MATLAB fuzzy logic toolbox to design a two-input and two-output fuzzy controller and using MATLAB SIMULINK for simulation of the control system, the results of the simulation show that the control process is smooth and the control effect is more ideal after using fuzzy control. The system is able to achieve the temperature and humidity limit alarm and automatically adjusted to the appropriate device to resume normal operation until the end of the whole drying, and able to monitore the changes of the dry cavity temperature and humidity values in real-time, you can view the historical data to facilitatly analysis the quality of materials after drying in order to obtain effective control strategies. The system can realize remote control, with a friendly interactive interface. By the experimental verification, the intelligent control system is stable, reliable, the control accuracy is improved greatly, the human and material resources are greatly reduced, the energy consumption is also reduced, the moisture content of dried material is very close to the ideal valuesvery, which realize the microwave continuous dryer automatic and intelligent.