中文摘要：

针对传统平行板电容传感器易受环境干扰，设计了一种差分结构的电容传感器，以实现籽棉质量流量检测。研究了环境温度和棉花品种对传感器电容信号响应的影响，并在不同含水率条件下，确定了籽棉质量流量与电容响应关系，建立了基于籽棉含水率、籽棉质量流量与相对电容变化率的拟合回归模型，并对模型进行验证。试验结果表明：差分结构电容传感器能很好地消除环境温度干扰，所建立的回归模型针对籽棉质量流量检测的平均相对误差为5．16％。

英文摘要：

Mass flow measurement during the crop harvest process is one of important ways of data collecting for precision agriculture. In this research, a method for detecting seedcotton mass flow rate was proposed. The principle of the method was based on the fact that the dielectric constant of air/seedcotton mixture between two parallel plates increased with seedcotton mass flow rate. In order to decrease the influence of environmental disturbance, a differential capacitive sensor was designed to perform the seedcotton mass flow rate measurement. One kind of seedcotton named Xinluzao43 was used as sample to study the influence of cotton moisture content on the output capacitance value of mass flow sensors, and the relationship of cotton mass flow and sensor output capacitance. Experiment results showed that, the relationship among cotton moisture content, mass flow rate and capacitance value could be described by a bivariate regression model. The change of ambient temperature and breed had no significant relationship with the sensor output. The average relative error of seedcotton mass flow sensor was 5.16%.