基于电容法的齿盘式棉花穴播器播种量传感器设计与试验  

Design and Experiment of Seeding Quantity Sensor for Cotton Hill-drop Planters Based on Capacitive Method

作　　者：周利明[1,2] 季雨希 牛康 韩璧蔓[1,2] 白圣贺 刘阳春 ZHOU Liming;JI Yuxi;NIU Kang;HAN Biman;BAI Shenghe;LIU Yangchun(Chinese Academy of Agricultural Mechanization Sciences Group Co.,Ltd.,Beijing 100083,China;State Key Laboratory of Agricultural Equipment Technology,Beijing 100083,China)

机构地区：[1]中国农业机械化科学研究院集团有限公司,北京100083 [2]农业装备技术全国重点实验室,北京100083

出　　处：《农业机械学报》2024年第S1期177-185,共9页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家重点研发计划项目(2022YFD2002400);兵团财政科技计划项目(2023AB014)

摘　　要：针对新疆地区广泛应用的齿盘式穴播器无导种管结构,常规光电传感器无法安装的问题,研究一种基于微弱电容信号获取与分析的播种传感器。通过对穴播器内取种过程分析,确定检测位置及极板外尺寸。以提高信号显著性和检测精度为目标,以可靠性为边界约束条件,建立三因素三水平响应面试验对电极结构参数寻优,并对传感器敏感单元屏蔽处理,集中场能。经改进后传感器敏感单元厚度0.64 mm,基础电容平均值13.94 pF,电容变化量为0.16 pF,有效提升信号显著性和检测精度。设计了以电容转换芯片AD7745为核心的电容信号采集模块。上位机通过对采集信号自适应阈值正交小波变换滤波,基于二阶导数寻峰获取种子实时播量。试验结果表明:在采样周期11 ms、穴播器转速20~30 r/min条件下,传感器具有较高的检测精度,实际播量和测量播量之间相对误差为-2.604%~1.836%,均小于5%。本文所设计的播种传感器为解决穴播器式播种装备播种检测问题提供了一种有效途径,对提高精量播种技术具有重要意义。To address the installation challenges of conventional photoelectric sensors in hill⁃drop planters widely used in Xinjiang,which lack seed guiding tubes,a seeding sensor was explored based on weak capacitive signal acquisition and analysis.By analyzing the seed extraction process within the seeder,the optimal detection position and external dimensions of the electrode plates were established.The primary objectives were to enhance signal significance and detection accuracy while ensuring reliability as a critical boundary constraint.To optimize the electrode structure parameters,a response surface methodology was employed,utilizing three factors at three levels.Additionally,the sensitive unit of the sensor was shielded to concentrate the electric field.Following enhancement,the thickness of the sensor’s sensitive unit was determined to be 0.64 mm,and a capacitance variation of 0.16 pF,effectively enhancing signal significance and detection accuracy.A capacitive signal acquisition module,centered around the AD7745 capacitive conversion chip,was designed.The upper computer processed the collected signals using adaptive threshold orthogonal wavelet transform filtering and employed the second derivative peak detection to obtain real-time seed sowing rates.Experimental results indicated that with a sampling period of 11 ms and a seeder rotation speed of 20~25 r/min,the sensor achieved high detection accuracy,with relative errors between the actual and measured sowing rates ranged from-2.604%to 1.836%,which were all less than 5%.The designed seeding sensor provided an effective solution to the sowing detection challenges associated with disc-type seeding equipment and played a significant role in advancing precision sowing technology.

关 键 词：棉花 齿盘式穴播器 播种量 传感器 电容法 滤波寻峰算法 

分 类 号：S223.2[农业科学—农业机械化工程]