【作者】 王佩东；

【导师】 曲立平； 李向奎；

【作者基本信息】 哈尔滨工程大学 ， 计算机技术， 2011， 硕士

【摘要】 我国是粮食大国,粮食安全贮存问题关系国家前途和命运,而收获的粮食必须经过干燥达到安全水分后才能长期贮存,但目前我国粮食机械干燥还未实现真正的自动化控制。本研究目的在于提高稻谷干燥机连续式干燥的自动化控制水平,提高干燥后稻谷水分的一致性,增强粮食产后干燥设备在国际市场的竞争力。本文以连续式水稻干燥机实物为研究对象,在实地采集数据的基础上,建立水稻连续干燥的物理模型,进而建立了数学模型,可计算连续干燥过程中水稻含水率变化情况,同时建立神经网络模型对干燥过程的控制进行仿真模拟。在实测数据的基础上,参阅了大量的文献资料。以薄层干燥理论为指导,将数学计算结果和实测值进行对比验证,调整了计算稻谷连续干燥的公式参数,对水稻连续式干燥过程进行了数学建模。在数学模型的基础上,对整个连续干燥过程进行模拟计算,讨论和分析了环境温度、环境相对湿度、高温风温度、低温风温度、风量、谷物初始含水率以及排粮速度因素变化与水稻排粮终含水率变化的关系。同时基于神经网络理论,建立了干燥过程控制的BP神经网络模型,模拟干燥过程的智能控制,也就是通过控制干燥通风量来抵消其它因素变化所带来的影响,从而使水稻排出时的终含水率趋于一致。本文以计算机和MATLAB为辅助工具,进行了连续干燥过程数学模型的模拟计算和干燥过程控制神经网络模型的仿真模拟。数学模型的计算结果和实测值基本吻合,可以用于连续式干燥过程的模拟计算,具有实际指导意义。BP神经网络控制模型通过学习后,预测值能够满足稻谷连续干燥过程控制的要求。最后设计了稻谷BP神经网络控制计算程序。更多还原

【Abstract】 China has a large need for food grain, the security storage for grain is related to our nation’s future and destiny. Grain must be dried to safe water content for long-term storage, but automation control is not really applied to machinery for grain drying. Purpose of this study is to improve the control level of automation for continuous flow grain dryers and moisture consistency of dried grain, as well as increasing the competitiveness of grain dryers in the international market.Taking the real continuous flow paddy dryer as a research object, many measured data are collected. Based on a physical model, a mathematical model is made to compute the paddy moisture during the drying process and then a BP neural network model is built for the control simulation of the drying process.On the basis of measured data and references and directed by the thin layer drying theory, through comparing between computed results and the measured results, some parameters in mathematical formulas are adjusted, then a mathematical model is made for continuous computation of the paddy drying process. According to simulation computation of this model, influences of many parameters including environment temperature, environment relative humidity, high and low temperature of drying medium, wind capacity, initial paddy moisture and paddy discharging speed (drying time) are discussed. A BP neural network model is built for computation of wind capacity in the control simulation of the drying process. That is, through the adjustment of amount of drying air to control the drying process as well as the paddy moisture and decrease the gap of the final moisture content of dried paddy.With the assistance of computer and MATLAB, a simulation computation of the mathematical model and a control simulation of the BP neural network model are made. Conclusions are drawn that the mathematical simulation result for the final moisture content of paddy is well in line with the measured data and the predicted values of BP neural network model meets requirements of the drying process control. Finally, a program is designed to calculate the control process of BP neural network in paddy dyring.更多还原