Design and Experiment of Pneumatic Cylinder Array Precision Seed-metering Device for Cotton

Xinjiang is the largest production base of quality cotton and commodity cotton in China. Sowing is one of the most important links which affects the development of cotton industry. In order to improve the precision and efficiency of seed-metering device for cotton, a pneumatic cylinder array precision metering device for cotton was designed, which combined the features of array suction and pneumatic clearing with side direction. The working principle and component of precision seeder were introduced, the key structure parameters were determined, and the mechanical model of single cotton seed during the air-suction filling process was established. In test, cotton seed Xinluzao 48 was selected as experimental material. Based on pre-experiments, the cylinder speed, hole diameter and vacuum pressure were taken as main impact factors, the quality of feed index, miss index and multiple index were taken as response indices, and the second orthogonal rotation combination test was executed, which used the Design-Expert software. The regression models were established, and effects of various factors on the performance indices were analyzed. The research gained the best combination of the parameters by using multi-objective optimization, which was as follows: the cylinder speed was 15.5 r/min, the hole diameter was 3.5 mm, and vacuum pressure was 4.2 kPa. Under the condition of the optimal combination parameters, the quality of feed index, miss index and multiple index were 93.5%, 2.0% and 4.5%, respectively. According to optimization parameter combination, the verification test was repeated five times, the results showed that the experimental results were basically consistent with the optimization results, and the sowing quality satisfied the requirements of precision sowing for cotton. The sowing adaptability experiment was carried out under the same conditions with three cotton seeds (Xinluzao 48, Xinluzao 52 and Xinluzao 60), whose overall dimension existed some differences from each other. All the qualities of feed index were more than 92%, all the miss indices were less than 3%, and all the multiple indices were less than 5%, indicating that when planting different cotton seeds, the precision seeder had certain adaptability to different varieties of cotton seeds. The study provided a theoretical reference for the design of pneumatic cylinder precision seed-metering device for cotton. © 2017, Chinese Society of Agricultural Machinery. All right reserved.