Abstract:
Maize is one of the most extensively cultivated grain crops in China. The high-speed precision seeding is required under land intensification, particularly for the optimal timing, entropy-adapted sowing, and yield enhancement. Among them, the air-suction precision seeding can be combined with the constrained seed guide and zero-speed seeding. The disturbing seed filling and multi-stage seed cleaning have been reliable for the high-performance seeding. However, the constrained seed guiding has been confined to the uncontrollable trajectory of seed migration, especially under the strong collision between the seed and the constrained seed guiding device at the high speed. Eventually, there is a sharp increase in the coefficient of variation of the seed spacing, when the seed is thrown. The large initial speed of the seed can be found, when leaving the seed plate in the high-speed corn planter. The collision and bouncing with the inner wall of the seed guide tube can also lead to the decrease in the qualified rate of the seed spacing. In this study, a high-speed seed guiding device with brush belt was designed to transfer the seed into the control wheel that assisted seed-brush synchronous belt. The direction control wheel was utilized with the opening/closing finger shafts to form the seed cavities during guidance. Single grain was sequentially deposited on the brush tubes. The stable transportation and zero-speed delivery were realized after the brush-belt rotation. The performance factors and their operational ranges were identified after structural optimization and theoretical analysis. The dynamic model was constructed for the rotary steering to the control wheel, as well as the transfer and seeding of the brush belt. The influencing factors on the steering trajectory of the control wheel were obtained as the installation angle of the control wheel relative to the seeding plate. The length of the brush and the diameter of the belt wheel were the influencing factors on the stability of the seed holding and seeding of the brush belt. A single-factor test was carried out on the directional control wheel that assisted the seed acceptance using Adams-EDEM coupling platform. The seed was fully met the guidance requirements, when the installation angle of the directional control wheel relative to the seed plate was 15°. The stable guidance trajectory was also achieved after simulation. The secondary rotation orthogonal test was carried out with the brush length and the pulley diameter as the test factors, and the qualified spacing rate, the multiple seeding rate and the missed seeding rate as the test indexes. The test results show that the qualified spacing rate was 96.03%, the missed seeding rate was 1.76%, and the multiple seeding rate was 3.48%, when the operating speed was 13km/h, the brush length was 24.9 mm, and the pulley diameter was 53 mm. The performance of the seed guiding device was verified at different operating speeds, according to the optimal combination of parameters. Once the operating speed was 12-16 km/h, the qualified spacing rate was not less than 94.3%, the multiple seeding rate was not higher than 3.92%, the missed seeding rate was not higher than 3.19%, and the damage rate was not higher than 0.19%. This finding can provide a strong reference to optimize the high-speed seed guide device.
