Studies On Intelligent Control System Based On Tobacco Leaf Curing

Tobacco leaf curing is the final links that determine the quality and production of the production practices of flue-cured tobacco. Advanced curing techniques can show the superior characteristic of mature tobacco leaf sufficiently, increase production and implement its use value.In past, natural ventilating up-draft barn was the main type of curing barn used in the production practices of flue-cured tobacco. This curing barn has the disadvantages of great operation error, ineffective feedback and lagged prospective results, thus it affects the quality of flue-cured tobacco. Although there is much improvement on techniques of tobacco leaf curing at present in China, many problems still exist. It is incomplete of the design of heating and ventilation and exhausting humidified air of curing barn. Though the control process overcomes the shortcoming of high work intensities and uneasy control of traditional curing, the regulation of temperature is lagged and the accuracy is hard to meet the high accuracy requirement of flue-cured tobacco techniques.Aiming at status quo, this paper summarizes and analyses the problems existing in the curing process and rebuilds curing barn and designs temperature and humidity control system whose hard core is intelligent controller based on domestic and overseas advanced tobacco leaf curing techniques and curing technology offered by tobacco experts. The systematic design includes three aspects as follows: rebuilding of curing barn, design of hardware circuit of intelligent controller and determination of intelligent controlling tactic. The main body of rebuilding curing barn is made of brick, tile and wood. The vertical stove uses coal as fuel. The rebuilding curing barn has a dynamical heating and forced ventilation and humidified air exhausting system. The whole circuit of intelligent controller utilizes C8051F310 SCM as its hard core, employs digital temperature sensor DS18B20 (DALLAS company) collecting and transforming the temperature and humidity data, and monitors changes of temperature and humidity in curing barn momently through an intelligent LCD terminal, and moreover, it can control machines such as delivering coal and supplying air based on optimal control curve of temperature and humidity in the process of tobacco leaf curing and using experts' controlling tactic, thereby assuring the temperature and humidity in curing barn changing according to control curve . The design shows schematic diagrams of curing barn and the whole circuit diagram of control part. According to controlling concepts mentioned above and requirements of tobacco leaf curing techniques, control arithmetic and procedure flow chart are achieved. The hard core of control circuit has already been finished and the results of test showed that the connection of circuit and the characteristic of electric were well. The design of Software procedure is in process owing to time limited.