小麦宽苗带撒播器弹籽板结构设计与优化

Structural design and optimization of seed separated plate of wheat wide-boundary sowing device

为了对小麦宽苗带撒播器进行结构改进和参数优化,该文以鸭掌型宽苗带撒播器弹籽板为研究对象,建立了以球面半径、安装倾角和跨度作为变量的球面型弹籽板数学结构模型,搭建了离散元仿真平台,以小麦籽粒横向均匀度变异系数作为作业效果评价指标,分析3个变量对宽苗带撒播器工作性能的影响,并根据试验结果对弹籽板的结构进行优化。单因素试验结果表明,球面半径在130～150 mm、安装倾角在30?～40?、跨度在80?～100?区间时,宽苗带撒播器具有较好的横向匀种效果;通过二次回归正交旋转组合试验,建立了3个变量与横向均匀度变异系数的回归方程,结果表明,影响小麦籽粒横向均匀度变异系数的主次因素依次为安装倾角、球面半径、跨度和安装倾角×跨度,其中安装倾角和跨度之间存在一定的交互作用,当球面半径、安装倾角和跨度分别为141.26 mm、35.53?和90.72?时,宽苗带撒播器具有较优的横向匀种效果,此时理论计算和仿真试验的横向均匀度变异系数分别为10.58%和9.21%,两者偏差仅为1.37个百分点,说明建立的回归模型准确;弹籽板最优结构参数组合下宽苗带撒播器台架和田间应用试验结果显示,小麦籽粒的横向均匀度变异系数的平均值分别为13.40%和12.10%,台架和田间应用试验的结果与仿真试验基本吻合,证明应用离散元法对宽苗带撒播器弹籽板结构参数进行优化的结果是可信的。该研究可以为宽苗带撒播器的弹籽板结构参数优化以及提升其横向匀种效果提供理论参考。

Wheat is one of the main grain crops in China.It has a great significance to ensure its sustained high and stable yield for maintenance food security in China.Studies have shown that the traditional wheat drill sowing technology is not suitable for the requirement of high and stable yield due to the bareness between rows,the insufficient utilization of land resources,the crowding between rows and plants,and the competing for water and fertilizer.Wide-boundary sowing was a new planting type of wheat,which can effectively improve the utilization rate of light,heat,water,fertilizer and land,it is meaningful to develop mechanized wide-boundary sowing technology.Wide-boundary sowing device is a core component of the technology.Structure and parameters optimization of wide-boundary sowing device were studyed based on the discrete element simulation technology,soil tank test and orthogonal test in this paper.The mathematical structure model of seed separated plate was established,spherical radius,installation angle and span were 3 key structural parameters of mathematical structure model.The discrete element simulation platform for wide-boundary sowing device,which mainly consists of particle factory,seed tube,cover plate for protect seed,side plate for support,seed separated plate and seedbed was set up.Taking the coefficient variation of wheat transverse uniformity as evaluation index,the influence of 3 key structural parameters on the performance of wide-boundary sowing device was analyzed,and the structure of seed separated plate was optimized according to the simulation results.The results of single factor simulation test showed that wide-boundary sowing device had relatively small coefficient variation of wheat lateral uniformity when spherical radius,installation angle and span at 130-150 mm,30°-40°and 80°-100°respectively.According to the results of single factor experiment,the quadratic orthogonal rotation combination simulation experiments were conducted,and the regression equations of 3 key structural parameters and coefficient variation of wheat lateral uniformity were established.The orthogonal results showed that the main and secondary factors affecting coefficient variation of wheat lateral uniformity were installation angle,spherical radius,span,interaction between installation angle and span,and there was a certain interaction between installation angle and span.When spherical radius,installation angle and span were 141.26 mm,35.53°and 90.72°respectively,coefficient variation of wheat lateral uniformity was minimum.in this case,the coefficient variation of wheat lateral uniformity of theoretical calculation value and simulation test value were 10.58%and 9.21%,respectively,and the deviation was only 1.37%,the regression model was accurate and credible.In order to validate the regression model established by simulation test and the optimization effect of structure parameters,a bench test of wide-boundary sowing device with the structure parameters optimization combination of seed separated plate was carried out.The results showed that the average coefficient variation of wheat lateral uniformity was 13.40%,and the deviation with simulation experiment results was 4.19%,which less than 5%,and considering there may be some errors in the bench test,so it was believed that the results of bench test was basically consistent with simulation test.This paper proved that the discrete element method was feasible to optimize the structural parameters of seed separated plate,the research results could provide references for optimizing the structural parameters of seed separated plate of wide-boundary sowing device and improving the performance of the wide-boundary sowing.