| Potatoes are tuber crops,most of which are sown with micro-potatoes or diced potatoes.Both micro-potatoes and diced potatoes have problems of large mass and irregular shape,which makes it difficult for traditional seed metering devices to achieve precise seeding of potatoes.Based on the research of potato seed metering device at home and abroad,this paper designs a pneumatic scoop-belt combined potato precision seed metering device for potato micropotatoes,which can realize single-grain precision seeding,and is equipped with an automatic seed feeding device.Through the EDEM-Fluent coupling simulation test and bench test,the optimal working parameter combination of the seed meter was obtained.The main research contents of this paper include:（1）Research on the characteristics of micro-potato seed potatoesThe measurement of the three-axis size,radius of curvature and other parameters of micropotato seed provides a reference for the design of potato seed scoops;The material parameters such as moisture content,density,static friction coefficient,rolling friction coefficient,and collision recovery coefficient of micro-potato seed potatoes are measured to provide data support for the structural design of potato seed metering devices and simulation experiments.（2）Structural design and theoretical analysis of micro-potato precision seed metering deviceBased on the material properties of micro-potato seed potatoes,the basic structure and working principle of the potato seed metering device were studied.Combined with the production mode and agronomic requirements of micro-potato sowing,a preliminary design of the seed metering scheme of the potato seed metering device was carried out.According to the characteristic parameters of the micro-potato material,the structure and size of the key components such as the scoop and air chamber of the potato seed metering device are designed and optimized.Kinematic analysis and dynamic analysis are carried out on the seeding process,and the parameter value range of each main component is determined to provide data support for simulation test and bench test.（3）Simulation test of the working process of the seed metering device based on EDEMFluentUsing the EDEM-Fluent coupling method to simulate the working process of the potato seed meter.The main influencing factors are the inclination angle of the seed metering device,the height of the seed layer,the belt speed of the seed metering belt,the wind speed of the positive pressure seed clearing duct and the negative pressure of the negative pressure air chamber.The main evaluation indicators are the missed seeding rate,qualified rate and replay rate of seeding.With reference to national standards and relevant agricultural norms,singlefactor simulation experiments and orthogonal experiments dominated by each factor were carried out.The influence of various parameters on the performance of the seed metering device is analyzed,and the structure and parameters of each component of the seed metering device are optimized.When the inclination angle of the seed metering device is 74.8° and the height of the seed layer is maintained at about 145 mm,the best seed picking effect is obtained,and the missed seeding rate is 1.04%.At the same time,the range of the bench test for each parameter is determined: the wind speed of the positive pressure seed cleaning pipe is25m/s～29m/s,the negative pressure of the air chamber is 3k Pa～5k Pa,and the movement speed of the seed scoop is 0.4m/s～0.6 m/s.（4）Bench test of potato precision seed metering deviceIn order to further obtain the optimal working parameter combination of each component of the potato seed metering device and verify the simulation test results.After the approximate parameters of each component of the potato seed metering device were obtained through the simulation test,the potato seed metering device prototype and the automatic seed supply system were processed.Through the bench test,the influence of the movement speed of the seed scoop,the wind speed of the positive pressure seed clearing duct and the negative pressure of the air chamber on the seed metering performance was analyzed.The results of the simulation test were verified.At the same time,the optimal combination of working parameters of each component of the seed metering device is determined: the inclination angle of the seed metering device is 74.8°,the wind speed of the positive pressure seed cleaning pipe is 28.2 m/s,the negative pressure of the air chamber is 4.5 k Pa,and the movement speed of the seed scoop is28.2 m/s,the moving speed of the scoop is 0.54m/s,and the height of the seed layer is maintained at about 145 mm.At this time,the leakage rate of the seed metering device is at least1.5%,and the pass rate is the highest at 94.3%.The seed metering performance is higher than the industry average. |
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