Design And Experiment Of American Ginseng Precision Seeder

American ginseng is not only a first-class Chinese medicinal material,but also a nourishing sacred product.In recent years,American ginseng planting industry in China has been developing rapidly,and 70% of the national American ginseng output comes from Wendeng,Shandong Province,accounting for about 23% of the world’s total.The planting ridge type of American ginseng in Weihai area is special,and the seeds need to be germinated,with poor fluidity and high price,which leads to the backward planting mechanization technology and low work efficiency in this area.Aimed at the above problems,this paper designed a precision seeder for American ginseng,and verified the performance of the seeder through field experiments.The main research contents of this paper are as follows:(1)Measurement of physical characteristics and parameter calibration of American ginseng seeds.The physical and mechanical parameters of the germinated American ginseng seeds were measured,and the triaxial size,sphericity,1000-grain weight,density,elastic modulus,shear modulus,Poisson’s ratio and contact parameters were obtained.The seed particle model of American ginseng was established in EDEM software,and the contact parameters between American ginseng seed and seed,stainless steel and ABS plastic were determined by bench and simulation calibration test.(2)Design of American ginseng precision seeder.According to the agronomic requirements of American ginseng planting in Wendeng,Shandong Province,a 14-row American ginseng precision seeder was designed,with a row spacing of 10 cm,an adjustable planting distance of 4.5～8cm,an adjustable planting depth of 0～4cm,and a working width of 1.5m m.The structures and working principles of American ginseng precision seeder,ditching-seed metering assembly and chain spoon precision seed metering device were described respectively.(3)Design of seed stirring device and seed filling performance test of spoontype American ginseng precision seed metering device.Based on the physical characteristics of American ginseng seeds,the chain spoon type precision seed metering device,which had good adaptability to ginseng seeds in the early stage,was selected as the seed metering component,and the structural parameters of the seed spoon and the seed stirring device were determined through theoretical calculation and stress analysis.Based on DEM-MBD joint simulation,the working condition of the seed metering device with stirring device was simulated.Through the simulation test comparison with the seed metering device without stirring device,it was found that the seed metering device with stirring device could effectively improve seed filling with the increase of seed metering speed.Through single factor simulation experiment,the influence of different arrangement of seed stirring teeth,relative installation position of seed stirring device,relative inclination angle of seed spoon hole,seed stirring and metering speed ratio and seed layer height on seed filling performance of seed metering device was analyzed,and the arrangement of seed stirring teeth,relative installation position of seed stirring device and relative inclination angle of seed spoon hole were determined.A test bench of seed metering device was set up,and a quadratic regression rotation orthogonal combination test was designed with the driving sprocket speed,the ratio of stirring and metering speed,and the height of seed layer as test factors,and the qualified index,leakage index,and refill index as test indexes.Through regression analysis and parameter optimization,it was found that the qualified index of seed metering device was 95.09%,the refill index was 3.98%,and leakage index was 0.93%when the driving sprocket speed was 102r/min,the ratio of stirring and metering speed was 0.25,and the height of seed layer was 82.5 mm.Under the same working conditions,the experimental verification showed that there was no obvious difference between the verification result and the optimization result,and the reliability of the optimization result was high.Through the performance test of the seed metering device,it was found that the variation coefficient of seed quantity was 4.14%,the average number of damaged seeds was 0.33,the seed spacing was uniform,and the damage rate was low.Therefore,the performance of the designed seed metering device met the design requirements.(4)Design of key components and whole machine test of American ginseng precision seeder.Double-disc ditcher was selected as ditcher,and the key structural parameters of double-disc ditcher were determined by theoretical calculation.Doubledisc ditcher and chain spoon seed metering device were assembled into a single form,and the assembly parameters are determined and the ditcher-seed metering assembly structure was designed.Designed the walking wheels to ensure better walking passability;The transmission system and structure of the whole machine were designed,and a six-speed governor was added to make the whole machine meet the requirements of adjustable sowing depth and plant spacing.Finally,according to the optimized parameters of the seed metering device structure and the design of key components,the three-dimensional prototype assembly and machine processing were completed,and the field test was carried out.When the working speed was 2.14km/h,the ditching depth was 2.5cm,and the plant spacing was 5cm,the qualified index of the designed precision seeder for American ginseng was 93.29%,the multiple index was 3.79%,the missing index was 2.92%.The working performance of the machine can meet the specifications,and it can be used in Wendeng,Shandong.