基于介电特性的联合收获机小麦含水率检测装置研究

谷物水分的快速测量对谷物准确测产、粮食快速收储、精准农业实施具有重要意义。针对联合收获机动态作业条件下小麦水分检测稳定性差、测量精度低等问题，基于小麦介电特性原理，设计一种联合收获机水分在线检测装置，提出一种动态连续取样、静态间歇测量的新方法，实现了联合收获机作业条件下，在线快速稳定检测小麦含水率。在线检测装置由机械动态取样部分、电机控制模块、传感器模块、数据采集模块、卫星定位模块和显示终端组成。其中传感器模块包括水分传感器、温度传感器和料位传感器。开展了静态验证试验和田间动态验证试验。试验结果表明，静态条件下，含水率在线检测误差在3%以内；在田间动态变化条件下，建立了基于介电常数和温度因子的水分检测模型，实测值和检测值相关系数达到0.92，在线检测误差小于5%。采用动态连续采样、静态间歇测量的方法显著提高了含水率在线检测的精度，为实现小麦精准生产提供了一种快速测量手段。

Development of Grain Moisture Detection Device on Combine Harvester Based on Dielectric Property

It is important to detect grain moisture content for grain yield monitor, grain accurate possession and precision agriculture. It limits the accuracy and stability of grain moisture on-line detection for the dynamic condition of combine harvester.A grain moisture on-line detection device on combine harvester was developed based on the principle of dielectric property. The dynamic constant volume sampling mechanism was proposed. With the help of the sampling mechanism, a method of dynamic continuous sampling and static interval measurement was also proposed. It could detect grain moisture on the operation condition of combine harvester. The device consisted of mechanical dynamic sampling part, motor control module, sensor module, data acquisition module, GPS module and a display terminal. Sensor module included moisture sensor, temperature sensor and grain height level sensor. In June 2020, experiments were carried out at Beijing Xiaotangshan National Demonstration Station of Precision Agriculture. Experimental results showed that under the static condition, grain moisture on-line detection error was within 3%. Grain moisture detection model was established integrated of permittivity and grain temperature. The dynamic experiment showed that the correlation coefficient between the predicted grain moisture value and that of standard value was 0.92. The relevant error was less than 5%. It could satisfy the practice need.