Study On Paddy Drying Control System Based On Analytic Fuzzy Method

Drying is an important step during post-harvesting paddy processing. In order to maintain the quality without being damaged, it is necessary to dry the paddy rice to the safe level of moisture content 14.0～14.5%(w.b.). In the course of paddy dried, the precise control of parameters for a dryer is the primary condition to protect the quality of paddy. At present, the constant drying temperature is frequently used for the most of the rice dryer, which constrains the further development of technology of paddy dried.In this research, an automatic control system was developed to control the drying temperature based on the various moisture content of paddy during drying process on a thin layer drying rig. According to a preliminary mathematical model, the objective drying temperature was obtained in PC depending on the online moisture content transmitted into PC through RS232, which was sent to the MCU with the function of detection of drying temperature, receiving temperature to precisely control dryer. On the basis of the control system, the paddy dried experiment under the variable drying temperature condition was performed. The research results were obtained as following:1. Moisture content of paddy was accurately recorded online during drying process on an improving experiment platform, which change the traditional manual Off- Line detection way for moisture to the automatically On-Line detection.2. Two monitor levels including upper machine using PC and lower machine using AT89C52 MCU was used to build the automatic control system.3. The designs of whole control system including circuit's hardware, software and the. programing ant jamming were completed depending on AT89C52 MCU as a core element.4. The temperature signal was collected by the electronic integration temperature sensors LM35 on the automatic control system, which is character of quick speed, high accuracy and good stability.5. A multi-layer fuzzy control method with simple and accurate properties, short responding timer, and strong anti-interference capability was applied in the MCU control system. At the control of drying temperature, this control system is quicker response time, smaller surplus-regulation and shocks and shorter transient-time than conventional temperature meters.6. Visual Basic6.0 software from Microsoft Corporation was used to develop the program for the up-level PC, which make full use of the resources of the PC to design a friendly interface and good computer operating environment, and provides dynamic data, data storage, data access, data...