Abstract: In order to investigate the fundamental reasons for the uneven spacing of the air suction precision seeder, this paper is based on the discrete element method theory and takes the seed delivery system composed of a seed metering device and a seed guide tube as the research object. The theoretical modeling of the seed delivery process was carried out, and the basic equation of the seed movement in the seed guide tube was obtained. The movement trajectory of the seed in the seed guide tube was simulated and collision analyzed using the discrete element software EDEM. The simulation results showed that when the initial collision angle between the seed and the seed guide tube was 4°-6.5°, and the reflection angle was below 2.5°, the motion trajectory of the seed was the most ideal. At this time, the seed slided down the wall of the seed guide tube and shot out along the tangent direction of the arc segment at the end of the seed guide tube. Based on this, the seeding monomer was restructured and verified through field experiments. The qualified index of grain spacing remained stable at 92% to 93%, and the coefficient of variation of qualified grain spacing was less than 30%. The performance indicators improved significantly.

Key words: pneumatic seeder, seeder unit, seed tube, motion trajectory, discrete element

摘要： 为研究气吸精量播种机播种株距不均匀的根本原因，基于离散单元法理论，以排种器及导种管共同组成的种子投送系统为研究对象，对种子投送过程进行理论建模，得到种子在导种管中运动的基本方程，并借助离散元软件EDEM对种子在导种管中运动轨迹进行仿真和碰撞分析。仿真结果表明：当种子与导种管首次碰撞入射角为4°~6.5°，反射角在2.5°以下时，种子的运动轨迹最为理想，此时种子沿导种管壁下滑，并在导种管末端沿圆弧段切线方向射出。并以此为依据对播种单体进行改制，进行田间试验验证，粒距合格指数稳定在到92%~93%，合格粒距变异系数小于30%，性能指标提升明显。

关键词: 气吸播种机, 播种单体, 导种管, 运动轨迹, 离散元