基于动态称量原理的泛函式播种施肥量检测方法

针对动态检测播种施肥量的测量系统易受振动干扰影响且难消除的问题，本文采用高压氮气弹簧的支撑力和S型传感器的拉力组合成称量式播量检测装置，利用压力和拉力之间存在力向相反、幅值呈比例的互补特性，提出了一种泛函式播量检测方法，该方法构建了以目标播量函数为变量的泛函，通过求取泛函极值确定目标播量函数。利用外槽轮式小麦播种施肥机平台，在不同目标播量（225、300、375kg/hm2）和不同车速（3、5km/h，3~7km/h变速）下开展了18组室外车载式小麦播种交叉试验，并应用泛函式播量检测方法获取累积播量和动态播量信息。累积播量的绝对相对偏差的最大值、平均值和标准差分别为5.61%、2.26%和1.58%；动态播量的检测数据在作业面积较小时（少于0.020hm2时）存在较大波动，随着作业面积的增加呈明显收敛趋势，动态播量稳定阶段（作业面积大于0.033hm2），所有测试最大绝相对偏差为9.61%，单次测试中，最大平均值为4.73%，最大标准差为1.97%。试验结果表明，泛函式播量检测方法能有效获取动态播量和累积播量信息，为播种施肥机的播量检测提供了一种测量方法。

Functional Detection Method of Application Rate Based on Principle of Dynamic Weighing

Dynamic weighing method is an ideal method for dynamic detection of application rate of fertilization and seeding, because the application is not limited by the measurement object and can directly obtain dynamic information. But it is difficult to be applied in practice because of its easily being interfered by environmental vibration. An application rate measuring device, where the supporting force from high-pressure nitrogen springs and the pulling force from S-type weighting sensors was combined for detection, was adopted in this research. A functional application rate detection method was proposed based on the complementary characteristics of the measuring device with opposite direction and proportional amplitude between the pressure and tension. In this method, a function with application rate function as a variable was constructed, and the target application rate function was finally determined by calculating the extreme value of the function. Eighteen groups of experiments, with a wheat seed fertilizer drill machine on a slight potholes cement road, were carried out at different target application rates (225kg/hm2, 300kg/hm2 and 375kg/hm2) and at different vehicle speeds (3km/h, 5km/h and 3~7km/h). And the dynamic and cumulative application rate were measured with the functional detection method. The maximum, average and standard deviation of the absolute relative error of cumulative application rate were 5.61%, 2.26% and 1.58%, respectively. After exceeding 0.033 hm2 of operation area, the maximum absolute relative deviation of the dynamic application rate was 9.61% in all tests, and the maximum average absolute relative deviation and maximum standard deviation were 4.73% and 1.97% in one test. The experimental results showed that the functional detection method can effectively obtain the dynamic and cumulative information of application rate, but the construction method of the function needed further research.