精密播种粒距的概率分布

考察精密播种的粒距形成过程，将种子落点坐标表示为期望值与正态随机偏差之和，导出落点间隔表达式，基于平稳随机过程建立了粒距的数学模型，演绎推导出粒距分布的分布函数、分布密度、一阶原点矩、二阶原点距和方差。结果表明：粒距同变量遵从一种源于方差相同位均值不同的多个正态总体的导出分布，可看作是不同分布参数正态分布的折尾与叠加。拟合优度检验的结果证实所求粒距分布对多种实测粒距样本拟合良好。分布密度图像的形状决定于分布参数，一般呈现为“多峰非对称”形式。

Probability Distribution of Seed Spacing of Precision Drilling

The placement formula was deduced from the seed placement coordinate which was expressed as the sum of expectation value and normal stochastic error based on the observation of the seed spacing forming process in precision drilling. On this basis, a mathematical model was set up, from which the probability density function, probability distribution function, and first as well as second order moments of the seed spacing were obtained. The result show that the seed spacing is a stochastic variable conforming to a deductive distribution of several normal distributions with the same variance but different mean value, and it can be regarded as the folding tail and addition of normal distributions with different distribution parameters. The results of goodness-of-fit test proved that the deduced seed spacing distribution coincided with various practical seed spacing samples. The graph of the spacing probability density whose shape relies on the distribution parameters usually takes the form of “multi-peak and non-symmetry”.