Research on optimal design method of maize seed tube based on DEM

Abstract

Abstract: In order to improve the uniformity of sowing by maize concentrate seeder, it is necessary to guide seeds into the seed ditch with reasonable seed tubes, and the optimal design of the seed tube of maize concentrate seeder is studied based on discrete element method. Firstly, based on the zero-speed seeding theory, the kinematic energy conservation equation is used to analyze the main curve of the seed tube, and the horizontal velocity equation of the seed at the outlet of the seed tube is obtained. Then the RSM optimization module design experiment based on Insight software, Combined with the horizontal velocity equation of the outlet of the seed tube, the angle α of the circular arc segment, the angle between the straight segment and the horizontal direction β, the height of the straight segment h₁, and the radius of the circular arc segment R are factors. At the same time, considering the analysis of the outlet horizontal velocity and the range adjustment of the actual agronomic seed spacing, the angular velocity of the seed discharge disc ω is increased as the factor, and the main curve parameters are optimized and solved in response to the plant spacing variation coefficient and the outlet horizontal velocity. In the range of ω=15-45 r/min parameters, the outlet horizontal speed is less than 0.1m/s, and the coefficient of variation is less than 5%, and the optimal parameter combination of the main curve of the seed tube is: α=25^o, β=11^o, h₁=200 mm, R=625 mm. According to the best parameters obtained, CATIA software was used to build a three-dimensional model and 3D printing was used for bench test. The coefficient of variation of the seeds obtained from the bench test was 11.58%, the pass index was 98.2%, the missed sowing index was 0.83%, and the reseeding index was 0.97%. The results show that the optimal design of the main curve of the seed guide tube is reasonable, provided a reference for the research and design of the seed guide tube of the corn precision planter.

Key words: precision planter, seed tube, discrete element, optimal design, coefficient of variation

摘要： 为提高玉米精量播种机播种均匀性，需要合理的导种管引导种子进入种沟，基于离散元法研究玉米精量播种机导种管的优化设计。以零速投种理论为基础，采用运动学能量守恒方程分析导种管主曲线，得到种子在导种管出口处的水平速度方程；基于Isight软件RSM优化模块设计试验，结合所得导种管出口处水平速度方程，以圆弧段夹角α、直线段与竖直方向夹角β、直线段高度h₁、圆弧段半径R为因素，考虑分析出口水平速度及实际农艺种子株距的范围调节，增加排种盘角速度ω为因素，以株距变异系数、出口水平速度为响应设计试验对主曲线参数进行优化求解。在ω为15~45 r/min参数范围下，以出口水平速度小于0.1 m/s，变异系数小于5%进行寻优求解，得到导种管主曲线的最佳参数组合为：α=25^o，β=11^o，h₁=200 mm，R=625 mm。根据所得最佳参数采用CATIA软件建立三维模型并3D打印进行台架试验，台架试验所得种子变异系数为11.58%、合格指数98.2%、漏播指数0.83%、重播指数0.97%，结果表明导种管主曲线优化设计合理，为玉米精量播种机导种管研究设计提供参考。

关键词: 精量播种机, 导种管, 离散元, 优化设计, 变异系数

CLC Number:

S223.2

Li Feixiang, Tang Kaiyi, Ge Yuefeng, Yang Dafang, Li Dezhi, Ma Jiajia. Research on optimal design method of maize seed tube based on DEM[J]. Journal of Chinese Agricultural Mechanization.

李飞翔, 唐凯怿, 葛越锋, 杨大芳, 李得志, 马佳佳. 基于DEM的导种管优化设计方法研究[J]. 中国农机化学报.

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