油菜直播地表土壤物理机械特性参数测量装置研究

针对油菜直播地表农田土壤物理机械特性参数室内测量费时费力、田间测量仪器功能单一等问题，设计了一种油菜直播地表土壤物理机械特性参数测量装置，实现集成测量土壤含水率、坚实度、粘聚力和内摩擦角4种土壤物理机械特性参数且测量结果可以通过手机APP实时储存显示。装置基于自走式移动平台实现行走控制，以STM32单片机为核心控制器，利用FDR传感器获取土壤含水率，通过圆锥贯入部件测量土壤坚实度和抗剪切强度参数(包括粘聚力和内摩擦角)。分析了装置的圆锥贯入部件和土壤含水率检测部件测量原理，设计了装置测量控制系统硬件电路及软件，开展了传感器标定试验，确定了柱式压力传感器、薄膜压力传感器和土壤水分传感器的输入输出响应关系。选取71个土壤样本，融合土壤含水率和基于圆锥受力平衡关系获取的摩擦因数，运用最小二乘法建立了土壤粘聚力和内摩擦角数学测量模型，模型决定系数R²分别为0.932和0.956。开展了装置田间测量试验，对土壤含水率、坚实度、粘聚力和内摩擦角进行集成测量，结果表明：相较于AYD-2型土壤坚实度仪、干燥箱干燥法和ZJ-D型直剪仪测量结果，油菜直播地表土壤物理机械特性参数测量装...

Measuring Device for Soil Physical or Mechanical Properties of Rapeseed Direct Planting Field

Considering the problem that the indoor measurement of soil physical or mechanical properties is time-consuming in laborious, and the function of instruments in the field measurement is single, a measuring device for farmland soil physical and mechanical characteristics was designed. The device can measure soil moisture content, firmness, cohesion and internal friction angle, and the measurement results can be displayed and stored in the mobile APP. It realized walking control based on self-propelled mobile platform. An STM32 single chip microcomputer was used as the core controller, an FDR sensor was used to obtain the soil moisture content, and the soil firmness and shear strength parameters, including cohesion and internal friction angle were measured through the cone penetration component. In addition, the measurement principles of the cone penetration component and the soil moisture content detection component of the device were analyzed, the hardware circuit and software of the device measurement control system were designed, and the input and output responses of cylindrical pressure sensor, thin film pressure sensor and soil moisture sensor were determined by sensor calibration test, respectively. Totally 71 soil samples were selected, and the mathematical measuring models of soil cohesion and internal friction angle were established by the least square method based on the sample moisture content and sample friction coefficient data obtained based on the conical force balance relationship. The model fitting coefficient R2 was 0.932 and 0.956, respectively. Field measurement experiments were carried out to measure soil moisture content, firmness, cohesion and internal friction angle. The results showed that compared with AYD-2 type soil firmness meter, oven drying method and ZJ-D type direct shear instrument, the average relative errors of soil firmness, soil moisture content, cohesion and internal friction angle measured by the measuring device of farmland soil physical and mechanical properties were 3.34%, 5.06%, 10.40% and 8.20%, respectively. The research result can provide a reference for the development of a fast and integrated measurement device for multiple physical and mechanical properties of farmland soil.