果蔬热风干燥含水率在线测量装置设计与试验

为了实现果蔬热风干燥的智能化控制,综合运用数学模型法与介电常数法,以IAP15W4K58S4型单片机为主控芯片,利用现有的高精度电容传感器AD7746,设计了基于MCU的果蔬热风干燥含水率在线测量装置。以鸡腿菇为研究对象,通过热风干燥试验,建立了可准确预测其热风干燥过程中含水率的数学模型和相对介电常数-含水率计算模型,并用程序语言将模型进行编码及编译并写入系统,实现了双模式测量。验证结果表明:该装置能准确测量鸡腿菇热风干燥过程中的含水率,测量结果相对误差小于3%。

Design and Experiment of Online Dual-mode Measuring Device for Moisture Content in Hot Air Drying Process of Fruits and Vegetables Based on MCU

In order to realize the intelligent control of hot-air drying of fruits and vegetables,in the paper,the methods of mathematical model and dielectric constant were combined to design an online measuring device for moisture content in hot air drying process of fruits and vegetables based on MCU,taking the advantage of Micro Controller Unit IAP15W4K58S4,and high-precision capacitive sensor AD7746.Setting Coprinus comatus as the research object,through the hot-air drying experiment,the mathematical model and the relation between relative dielectric constant and moisture content were established,which could accurately calculate the moisture content during the hot-air drying process.The models were coded,compiled and written into the measuring system.The system realized dual-mode measurement.The experimental verification results show that the device can accurately measure the moisture content in hot air drying process of coprinus comatus,and the relative error of measurement results is less than 3%.