Abstract: Aiming at the problem of reduced seeding performance of the airsuction wheat seed metering device due to poor seed filling, a wheat airsuction precision seed metering device that assists in seeding and stirring the seed tray is designed. This type of seed metering device can use the hole boss to disturb the population during the seed filling process and at the same time, use the stirring plate to increase the dispersion of the population and improve the filling performance. In the seedcarrying area, the seeds are more easily stabilized and absorbed by the hole boss, reducing the negative pressure required for seed adsorption. EDEM was used to simulate the discrete element population of 4 different design seeding discs, and the variation of the average population velocity and the normal stress beating of the population of each seeding disc was analyzed. Taking the speed, air chamber pressure and the inclination angle of the stirring plate as factors, the orthogonal bench test was carried out on the optimal seeding plate designed. Through the variance analysis of the test results, the goodness of fit and regression equation for each test factor combination of the seeding performance index were determined. Finally, the multiobjective optimization of experimental factors was adopted, with the optimal conditions being the largest qualified index and the smallest replay and missed index. The best performance parameters for the designed seed metering device were obtained: the seed metering disk speed was 36.7 r/min, the air chamber pressure was -3.6 kPa, and the inclination angle of the stirring plate was 26.2°. The optimized results were tested and verified, and the error between the bench test results and the theoretical calculation results was less than 5%. This research can provide a reference for the optimization and improvement of wheat suction precision metering devices.

Key words: wheat, air suction seed metering device, discrete element method, orthogonal test

摘要： 针对气吸式小麦排种器因充种效果不佳导致排种性能下降的问题，设计一种辅助托种、搅种种盘的小麦气吸式精量排种器。该型排种器能够利用型孔凸台在充种过程扰动种群，同时利用搅种板增加种群的离散度并提高充种性能；在携种区种子更易在型孔凸台的托持作用下稳定吸附，减小种子所需吸附的负压。运用EDEM对4种不同设计的排种盘进行种群离散元仿真，分析各排种盘的种群平均速度和种群法向应力跳动量的变化规律。以转速、气室压强和搅种板倾斜角为因素，对所设计的最佳排种盘进行正交台架试验，通过试验结果的方差分析，确定各试验因素对排种性能指标的拟合优度及回归方程。最后，采用试验因素的多目标寻优，以合格指数最大，重播、漏播指数最小为寻优条件，得出所设计排种器的最佳性能参数：排种盘转速为36.7r/min，气室压强为-3.6 kPa，搅种板倾斜角为26.2°。对优化后的结果进行试验验证，台架试验结果与理论计算结果误差小于5%。该研究可为小麦气吸式精量排种器优化改进提供参考。

关键词: 小麦, 气吸式排种器, 离散元法, 正交试验