颗粒肥料质量流量传感器设计与试验  

Design and Experiment of Mass Flow Sensor for Granular Fertilizer

作　　者：贾洪雷 温翔宇 王刚[2] 刘慧力[2] 郭慧 JIA Honglei;WEN Xiangyu;WANG Gang;LIU Huili;GUO Hui(Key Laboratory of Bionic Engineering,Ministry of Education,Jilin University,Changchun 130022,China;College of Biological and Agricultural Engineering,Jilin University,Changchun 130022,China)

机构地区：[1]吉林大学工程仿生教育部重点实验室,长春130022 [2]吉林大学生物与农业工程学院,长春130022

出　　处：《农业机械学报》2020年第S01期130-136,共7页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家自然科学基金项目(31901408);国家重点研发计划项目(2017YFD0700904);吉林省科技发展计划项目(20180414074GH)。

摘　　要：变量施肥具有提高肥料利用率、保护生态环境、节约农业生产成本等优点,但目前还没有得到广泛的应用,除了难以获得变量施肥的处方图之外,缺乏闭环检测也是原因之一。闭环控制是实现变量施肥的关键之一,与间接测量排肥轴的转速相比,实时检测肥料的质量流量更为准确。本文基于静电感应原理,设计了一种颗粒肥料质量流量传感器。由于颗粒肥料之间、颗粒肥料与空气、颗粒肥料与排肥管之间的摩擦和碰撞,颗粒肥料会携带一定量的电荷,因此本研究设计了环形电极来检测电荷强度,并利用电流放大电路输出感应电流。通过标定质量流量与感应电流的关系,获得了实时的肥料质量流量。搭建试验台对该颗粒肥料质量流量传感器进行检测,试验台主要包括动态信号采集系统、肥料箱、电流放大器和环形电极传感器。以大颗粒尿素(CO(NH2)2)、过磷酸钙(Ca(H2PO4)2·H2O)和氯化钾(KCl)为研究对象,其平均容重分别为0.7、1.2、1.1 g/cm^3。根据施肥装置的物理参数,通过调整排肥轴转速可获得近似的目标质量流量,目标质量流量的范围是3~15 g/s,增量为1 g/s。对于每个质量流量,进行了4次重复。每次重复30 s,施肥装置与信号采集系统同时启动。利用平均感应电流和平均质量流量建立回归方程,采用插值法得到实时质量流量。随后,对每种肥料进行25次试验,从而检验本文中颗粒肥料质量流量传感器的测量精度,每次试验的目标质量流量由5个随机质量流量组成,每个质量流量下持续排肥6 s,用天平称量30 s内的实际质量,通过积分质量流量和时间曲线计算检测质量。采用SPSS 22.0软件对试验结果进行统计分析,分析表明,大颗粒尿素、过磷酸钙、氯化钾的检测误差分别为3.9%、5.1%、5.9%,相应的标准差分别为5.21、7.98、11.29。检测质量与实际质量无显著性差异(P>0.1),大颗粒尿素、过�Variable rate fertilization has the advantages of improving fertilizer-utilization efficiency,protecting ecological environment as well as saving agricultural production cost.But it has not been widely applied yet,besides it is hard for getting the prescription figure,lacking closed-loop detection is another major reason.Closed-loop control is one critical step towards realizing the variable rate fertilization,compared with the indirect measurement which monitors the axis speed,it is more accurate by monitoring the real-time mass flow rate.If there existed the fertilizer caking that blocked the fertilizer apparatus,it is useless for monitoring the axis speed.Based on the electrostatic induction theory,a sensor that could monitor the mass flow rate of granular fertilizer was designed.Owing to the frictions and collisions between the granular fertilizer and the air,the granular fertilizer and the fertilizer tube,as well as the frictions and collisions among the granular fertilizer themselves,therefore,the granular fertilizers would carry a certain amount of electric charges.One ring electrode was designed to detect the strength of the electric charges,subsequently,a corresponding current amplifying circuit was utilized to export the induced current.The real-time mass flow rate could be obtained by calibrating the relationship between it and the induced current.One test-bed was established in order to finish the task,the test-bed mainly included one dynamic signal acquisition system,one fertilizer box,one current amplifier and the sensor.Large granular urea(CO(NH2)2),superphosphate(Ca(H2PO4)2·H2O)as well as potassium chloride(KCl)were chosen as the research objects,their mean bulk densities were 0.7 g/cm^3,1.2 g/cm^3 and 1.1 g/cm^3,respectively.According to the physical parameters of the fertilizer apparatus,the approximate target mass flow rates could be acquired by adjusting the axis speeds,and the target mass flow rates were ranged from 3 g/s to 15 g/s with increment of 1 g/s.With respect to each mass flow rate,

关 键 词：颗粒肥料 质量流量 变量施肥 排肥试验台 静电感应 传感器 

分 类 号：S224.21[农业科学—农业机械化工程]