Development Of The Grain Dryer Control System

In recent years, with the emphasis on agricultural development in our country, food drying problems are gradually getting attention. Every year, the grain losses due to mildew and germination deterioration in the storage, transportation, processing and other sectors,which caused by shed wet weather, or dry too late to achieve the standards for safe storage,reach 5% of the total gain output. Therefore, the demand for grain dryer is also growing up.The key technology in the grain drying process is the design of control system, traditional control methods are difficult to solve the problem of large time delay line and the control precision, etc. Thus, the automatic control system of continuous mixed flow grain dryers is developed in this paper. Through detecting grain temperature, hot air temperature, water temperature, grain moisture in the process of grain drying to provide a theoretical basis for the control system. In view of the problems in the process of grain drying and the advantages of digital signal processor, DSP, use TMS320F28335 produced by TI as the core controller of control system. And combine the temperature filed simulation and control system to ensure the gain quality after drying. Contents of this paper are mainly the following aspects.Firstly, introduce the current situation and development trend of grain dryer control system, analyze the problems in the traditional control system, propose the overall program, DSP as controller of grain dryer control system, and ultimately determine the overall structure of this article.Secondly, introduce the structure of grain dryer designed in the issue, including drying tower and hot water-hot wind stove, and analyze its technological process in detail.Then, simulate and analyze the temperature field of grain drying process using FLUENT in ANSYS software, optimize the structure of grain dryer. And the temperature of hot air influence on grain drying process was analyzed to determine the limits of hot air temperature in the safe range of food.Finally, according to the functions and requirements of grain dryer control system, use TMS320F28335 as a core controller, CCS as a development environment, modular method to design the control system and related hardware and software, use fuzzy control to control the dyer.