Abstract
To improve the seed-filling performance of pneumatic precision seed metering devices for small-seeded crops, a U-shaped seed agitation plate and a combined-type agitation plate were developed. The agitation performance of cylindrical, U-shaped, and combined-type agitation plates was evaluated using the average and maximum velocities of the seed population as quantitative indicators. A three-factor, three-level simulation experiment based on the Discrete Element Method (DEM) was conducted, with agitation plate type, rotational speed, and knob height as the main factors. The optimal parameter combinations were determined as follows: for millet, a combined-type agitation plate with a rotational speed of 24.85 r/min and a knob height of 8.36 mm; for broomcorn millet, 24.17 r/min and 7.96 mm; and for rapeseed, 22.93 r/min and 8.57 mm. Bench experiments were carried out to validate the optimized combined-type agitation plate. The seed-filling rates reached 99.3%, 100%, and 99.7% for millet, broomcorn millet, and rapeseed, respectively. The results indicate that the combined-type agitation plate significantly improves seed mobility and filling performance, providing an effective solution for precision seeding of small-seeded crops.