Fuzzy Control Theory Based Monitoring And Control System Of Temperature And Humidity Of The Granary

Temperature and humidity of grain affect grain storage is an important impact factors, and they are interactive. Temperature and humidity control of grain would inevitably lead to bad fever and mildew, and easily produce a chain reaction, resulting in the loss of irredeemable. Controlling to the temperature and humidity directly affect the performance of grain storage system. Therefore, the grain temperature and humidity monitoring and control technology in the application of agriculture is very important. This thesis studies the temperature and the humidity control system of the granary based on the fuzzy control theory, the main research results are as follows: The thesis designs monitor and control system of temperature and humidity of granary based on the fuzzy control theory. The system is consisted of temperature and humidity sensor, control circuit, monolithic processor and computer. Monolithic processor is in charge of the collecting of temperature data and communication with the computer. Control circuit is designed with FPGA technology, and it collects the humidity data and computes the derivation and changing rate of the humidity. Moreover, the control circuit controls temperature and humidity with fuzzy control using the fuzzy control algorithms. Monolithic processor communicates with the computer with RS485 bus, and thus the computer is able to record the data in the real time and show the changing value and curve of control procedure. This system realizes to control the temperature and humidity of granary in real time, which enables managers to grasp the situation of temperature and humidity of granary.The thesis uses FPGA to design the control circuit, which simplifies the systematic composition and the outer-ring digital circuit. It enables the system be easily extended and improved. Signal processing, control, detection and defend are integrated in the inner system, which decreases the volume of system, shortens the time of designing, which enhances the reliability. The system is equipped with the power driven, protection and power circuit, and the system can finish the signal collecting, processing and control, which save the design cost. The integration scale of the system is big. The advantage is fitted to the demand of high precision and integration for the current electronics products.This thesis applies the temperature sensor DS1820 and the humidity sensor HS1101 whose input is digital, and combing the HS1101 and 555 timer to constructs the oscillation circuit whose output is the frequency impulse signal which is the linear relation with the temperature. The impulse signal is input to FPGA for counting. Thus the signal of temperature and humidity sensor is not large amplification and A/D transformation, which decreases the testing error. The sample machine of this system is realized and the debug is passed. The expected result is obtained through the sample machine.