Working Process Analysis and Parameter Optimization of Millet Hill-Drop Seed Metering Device

Due to the small size, light weight, and impurities of millet, the existing seeders have poor quality when sowing millet, this study analyzed the working process of the pneumatic-mechanical combined seed metering device, established the equations of seed movement in the seed filling zone, seed cleaning up zone, seed carrying zone and seed dropping zone by dynamic theory. The theoretical factors affecting the sowing quality were clarified in order to improve the sowing effect of the millet hole sower. Vacuum degree, suction hole diameter, and hole wheel rotational speed served as the test factors, and qualifying rate, reseeding rate, and missing rate served as the evaluation indices in a three-factor, three-level orthogonal test. Better parameter combination is obtained through range and variance analysis: Vacuum degree is 2.0 kPa, suction hole diameter is 1.0 mm and rotating speed of hole wheel is 20 r/min. Verification tests were performed to ensure that the pass rate is 93.9%, reseeding rate is 3.1% and the missing rate is 3.0%, meeting the criteria for millet hole sowing. The results of this study can be promoted and applied in the research and development of millet hole sowing seeders.