New Intelligent System Of Measurement And Control For Grain Dryer

Our country is rich in food production, grain drying is not only related to farmers’ income, it is related to the economic benefits of grain depot and the economic interests of country, it is related to the steady progression of agriculture and rural society. Corn is one of the main content in our country’s grain drying, and it is very difficult to dry in the grain varieties. We have been used tower type dryer to dry corn, this type of dryer has great capacity of production, and the corn’s precipitation rate is also quick. The automatic control in the grain drying is one of the important measures to ensure the quality of the grain after drying, and it will create great economic and social benefits.This study is some parts of the Jilin province major scientific support project(20096036). Based on the theoretical analysis and experimental study, aiming at the drying process of the cross-flow combination dryer, this paper establishes mathematical model of drying process, combining the application of the fuzzy-neural network in the drye r, exploits an intelligent control system, to test and control the influence factors in the drying process. The paper’s full text is as follows:(1) In this thesis the writer expounds the status quo and the trend of the food drying machinery at home and abroad, introduces the development process of the control system in the food drying machinery at home and abroad, introduces the development of the fuzzy-neural network, and the use in the food drying machinery, the writer combines the problems of the control system in the food drying machinery, enumerates this paper’s research content and practical significance.(2) The writer describes the basis theoretical of the fuzzy control, the neural network and the fuzzy-neural network, introduces the learning method of the fuzzy set, the fuzzy inference, the fuzzy control system, and the neural network, introduces the fundamental of the model recognition and the identification of the fuzzy-neural network model.(3) The writer expounds the mechanism of drying process, the drying principle of the cross-flow combination dryer, calculates the average moisture content, the average food temperature and the drying time in the drying process, contrasts and analyses the results of the the dynamic simulation of the drying process and the experimental results.(4) The writer makes a comment about the application of the fuzzy-neural network in the automatic control, makes a model identification of the thermal process in the dryer, uses the BP neural network in the dryer, and confirms the input variables, output variables and domain. (5) To design the hardware and software of the intelligent control system. One part of the system is the connection between the touch screen and PLC, and edit the program for them.Through the combination of PLC and the touch screen, to achieve the automatic control of the dryer, and the real-time monitoring of the material location, the hot blast temperature, and the grain’s moisture. The other part of the system is the connection between the touch screen and MCU, and edit the program for them. Through the single chip microcomputer to implement the collect and control the temperature of the hot air, to implement the collect the value of the working voltage, to achieve the communication and set up online with the moisture sensor, to achieve the adjustment control of the frequency converter. The system can measure the grain’s moisture content, and compare with the requirements of themoisture content, according to the difference between the measured moisture content and the requirements of themoisture content, to adjust control variables, and to reach the requirements of themoisture content. Use the design of the neural network to realize the intelligent control.(6) Use the designed system of the measurement and control combined with the cross-flow combination dryer, to debug the system, and improving and perfecting constantly.Completed all of the above steps, this intelligent control system matches with the dryer, it can realize the real-time automatic control, improve the efficiency of the grain drier, show the grain’s moisture and the running status of the system, use the neural network to control the drying process. To apply the new intelligent system of measurement and control for grain dryer in practice, the dryer’s human-computer interface will be improved, the designed is more scientific, the control is more hommization, it will improve the efficiency of the grain drier. Using the touch screen will improve the service life of the man-machine interface greatly, improve the convenience of the running attention of the machine, the reliability and stability are also improved, and the level of complexity of the wiring is also reduced, finally it realizes the promoting the level of intelligence of the dryer.