The primary objective of this study was to develop a capacitance - based biomass proximity sensor with the performance characteristics necessary to detect the presence of biomass (e.g., corn stalks). The detection and quantification of corn stalks under harvest conditions was chosen as an example application of this technology. In this study, a non-intrusive, capacitive, single-sided biomass proximity sensor was developed, and the suitability of this sensor to biomass population quantification was evaluated. A number of capacitive sensor patterns were simulated using the finite element method, and then the patterns were fabricated and tested in the laboratory. The results showed that the optimal operating parameters of R1 and R2 in oscillator design are 43 kΩ and 169 kΩ, then the basic output frequency of the oscillator is 245 kHz. The best operating parameters of two external capacitors(C11 and C12) and three external resistors (R11, R12 and R13) in PLL circuit are 10 nF, 1 200 pF, 100 kΩ, 50 kΩ and 200 kΩ. Meanwhile, the field test results showed that the sensor can effectively identify the presence of corn stalks.%研究开发一种电容式生物质近距离传感器,该传感器具有检测生物质(如玉米秸秆)存在与否的功能.在收割条件下,检测和量化玉米秸秆是这一技术的一个应用示例.在这项研究中,开发了一个非侵入型、电容式单面生物质逼近传感器,并对该生物传感器是否适合生物质数量的量化进行了评价.利用有限元方法对一些电容式传感器模型进行了模拟,然后做出了这些传感器并在实验室进行了测试.结果显示,振荡器的设计R1和R2的最佳操作参数分别为43 kΩ和169 kΩ,此时该文氏振荡器的基本输出频率是245 kHz.锁相环电路中两个外部电容(C11和C12)和三个外部电阻(R11,R12和R13)的最佳操作参数为10nF、1 200 pF、100 kΩ、50 kΩ和200 kΩ.同时,田间测试的结果显示,该传感器可以有效地鉴定玉米秸秆的存在.
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