Design and experiment of air-assisted high speed precision maize seed metering device

In order to meet the requirements of maize precision seeding under high-speed conditions, from the working principle, we designed a high-speed precision seed metering device that could fundamentally solve the problems of poor filling performance and complex structure caused by high-speed operation. The device used the centrifugal force generated by high-speed operation to fill and clean seeds, and traditional seed stacking was changed into a gas-filled seed by means of gravity filling. Theoretical analysis and parameter design were carried out on the shape of seed tray, hole insert and seed plate. Seed supply mechanism was used for seed supply, and venturi tube was used for orderly gas blowing, and plug of type hole was matched with seed plate to fill and carry seeds, and changed width of the seed plate to clean seeds, and gravity of seeds and driving force of airflow were used for seeding. Single factor test was carried out on working speed of seed meter device, seed feeding speed and wind pressure. The qualified index, missing index and multiple index were used as test indicators to obtain the influence of various factors on seeding performance. The principle and structure of seed metering device was different from conventional seed metering device. In the case of increasing working speed of seed metering device, it did not increase missing index, but decreased and basically went to zero. When wind pressure was 130 Pa and seed feeding speed was 1 kg/min, the seeding performance was best when working speed was 9.8 km/h. When wind pressure was 130 Pa and working speed was 14.4 km/h, the seeding performance was best when seed feeding speed was 1.2 kg/min. When seed feeding speed was 1.5 kg/min and working speed was 14.3 km/h, the seeding performance was best when wind pressure was 465 Pa. In order to obtain the best performance parameter combination of seed metering device, the ternary quadratic regression orthogonal rotation combination test was carried out with above factors and test indexes, and the mathematical model between test index and test factor was established, and working principle and structure were obtained. Working speed had no significant effect on missing index for this metering device. The multi-objective optimization of the regression equation was carried out by using the response surface method. The optimal parameter range was: working speed was 9 km/h, seed feeding speed was 1.91 kg/min, and wind pressure was 492.17 Pa. Qualified index was 93.14%, missing index was 1%, and multiple index was 5.86%. It was verified by experiments and basically consistent with optimization results. It can be seen that working principle and structure of metering device had a low missing index, and missing index was not increased due to increase of working speed. It showed that this air-assisted high-speed maize precision seed metering device solved the problem of difficult to fill in high-speed operation, and its seed cleaning structure was simple, and could maintain good seeding performance under high-speed working conditions. It provided a reference for design and optimization of high-speed precision metering devices.