目前我国在检测粮库有效的储粮数量时仍经常采用一种传统的方法,即压力传感器法。虽然这种方法被广为使用,但其测量精度差、没有很好的代表性,而且所需的维护成本高。为了克服这些缺陷来得到有效的储粮数量,该文提出了一种新型的研究方法,即采用甚高频电磁波来对大型粮堆内部的密度进行快速检测。根据电磁波的反射和折射在粮堆不同深度处的不同的原理得到粮堆表层介电常数,之后利用菲涅尔公式并结合此表层介电常数反演出粮堆其他层介电常数分布。再结合介电—密度这个经验模型,将粮堆各层的介电常数分布转换为密度分布,进而将粮堆整体的三维立体密度分布图模拟出来。根据实验结果分析,发现此种方法检测精度高、检测速度快,较之传统方法,其在大范围的检测中更为适用。
To the problem that we lack effective detection technique for grain storage amount,a new detection technique was studied by using very high frequency(VHF) electromagnetic wave and was applied in detecting density distribution in huge grain pile,which may overcome low detecting accuracy,high maintenance costs under-representation and other shortcomings deriving from triditional pressure sensor methods.Using principles of reflection and refraction of electromagnetic wave,we first obtained surface dielectric constant of grain pile,then according to Fresnel's formula and using the surface dielectric constant,inverted dielectric constant distribution of other layers.At last,according to a empirical model called Dielectric-Density Model,we converted dielectric constant distribution to density distribution and then simulated the three-dimensional density distribution of the whole grain pile.The experimental results showed that the method proposed in this paper has the better detecting accuracy and speed and more adapt to a wide range of detection compared to triditional methods.