Structure Design Of Double-row Scoop-type Seed Metering Device And The Study Of Seed-filling System

The development of precision agriculture puts forward a higher demand for the refined design of agricultural machinery.Corn,as the economic crop that is second only to wheat and soybean,plays a vital role in China's grain reserves.At present,corn leaching machines on the market generally have serious leaks,which endanger national food security and farmers'farming benefits.Therefore,there is an urgent need to design a corn seed meter that can achieve single seed precision sowing under high speed operation conditions.This study designed and developed a seed metering device that can achieve corn precision seeding under high-speed operation,and carried out corresponding experimental research,which has important reference and practical significance for the design of corn precision seed metering device.Based on the analysis of the research at home and abroad,in response to the defects of the common scoop wheel type metering device,a double-row scoop wheel type precision seed meter with an automatic replanting device was improved and designed.The experimental research and verification were carried out.The specific research contents and conclusions are as follows:?1?Study on the physical properties of corn kernels.The characterization experimentations of three representative corn kernels,namely Zhongyuan 505,Kerui Zixiang and Kerui sweet potato F1 was carried out,including geometric characteristics of corn kernels,quality of corn kernels?per 1000 grains?,corn kernel density,static friction between corn kernels and steel plate and itself.By measuring several characteristics of corn,it is classified into three types:long cone,rectangle and near sphere,which provides basic parameters for subsequent seed meter design and simulation analysis.?2?Structural design of the double-row scoop wheel type seeder.Aiming at the problems of low working speed of common scoop wheel type corn seed metering device and large leakage rate and replay rate during high speed operation,through the research on the seed spoon,the partition plate,the double-sided seed wheel and the seed shell,a new seed metering device with double-twist structure was improved and designed.Based on the working principle of the seed metering device,the main structural parameters of the seed metering device are determined through theoretical calculations:The opening angle of the spoon nest is?₁=28°,the angle of the seeding area is?₃=75°,the size of the seeding port is the short axis d₂=54mm,the long axis d₃=80mm,and the size of the seeding port is the width d₆=15mm,length d₇=10mm.?3?Dynamic research and simulation analysis of double-row scoop wheel type seed metering device.Taking the structure characteristics and working principle of the double-row scooping type seeding device as the cutting point,the dynamics of the seed in the seedling,clearing and protecting areas during the acceleration of the seeding device were analyzed.Deducing the maximum acceleration amax that ensures that the kernel does not fall from the seedling in the seedling and clearing areas,and determining a stable and reliable detection position in the nursery area.Simulation study on seeding performance of double-row scoop seeds before and after acceleration by EDEM.The results show that in the range of 4km/h to 8km/h,the effect of variable speed replanting is best,and the effect of acceleration on seeding performance is less than 2%.This provides a theoretical basis for the design of subsequent replanting systems.?4?Design of automatic replanting system.Through the demand analysis of the replanting system,the overall scheme and structural scheme of the automatic reseeding system are designed,and the position and size of the detecting hole are determined.The selection of the hardware part of the automatic replanting system and the encoding of the software part are completed.?5?Prototype and test of meter.The automatic seed replanting system designed in this paper performs the automatic reseeding performance test at the seeding speed of 4km/h to8km/h.The results show that the average missed seeding rate of the improved rear seed metering device is reduced from 9.6%to 1.33%,and the seeding pass rate can reach over90%.It shows that this design can reduce the corn leakage rate to a large extent,and the seeding effect meets the requirements of precision seeding.