摘要
国内目前的农业灌溉过程中,主要利用土壤和环境湿度来判断作物缺水状况。在研究平行板电容传感器工作原理的基础上,提出了用电容传感器测量植物含水情况,并提出在测量中将电容极板间被测物质和间隙空气抽象为固、液、气三相的方法,理论上分别建立了用于植物水分测量的三相介质的并联、串联数学建模,并做了数值模拟分析。分析认为在一定的激励信号作用下,平板电容的电容值与极板间被测介质含水率呈对应关系,得出了平行板电容传感器可以实现直接针对植物含水情况测量的结论,解决了间接测量的滞后性和准确性差的问题,确定了三相介质并联的建模方法可以作为传感器系统理论分析的最佳方案。在理论分析可行的基础上对传感器电路结构设计做了初步分析、介绍。
At present, the judgment of water content condition of plant is mostly through the soil and environment moisture. On the basis of the study on the work principle of the parallel plate capacitance sensor, the method, in which capacitance sensor is adopted to measure the water content of plant and the measured substance and air between the capacitance plates are abstracted as solid phase, liquid phase and gas phase, is put forward in this paper. The mathematical model with the parallel and series connection of three phase medium for the water content measurement is established and numerical simulation is conducted. It is found that the plate capacitance value has corresponding relation with the water content of measured medium. So the parallel plate capacitance sensor can directly measure the water content of plant and the problems of time-lag and low accuracy are solved. The model-establishing method of parallel connection of three phases medium can be taken as the optimal solution for the theory analysis of sensor systems. Moreover, based on the theory analysis, the structural design of sensor circuit is preliminarily analyzed and introduced in this paper.
出处
《节水灌溉》
北大核心
2008年第5期31-33,37,共4页
Water Saving Irrigation
关键词
传感器
植物
电容
精量灌溉
数学建模
sensor
plant
capacitance
accurate irrigation
mathematical model
