| American ginseng(Panax quinquefolium L.)is a perennial medicinal herb of the genus Ginseng in the family Pentacostaceae,and is the main ingredient of many medicines with high medicinal value.In recent years,the planting area of American ginseng in China is increasing year by year,and has gradually become the third largest planting country and the largest purchasing power country in the world.Western ginseng has strict requirements on the growing environment and operation process,and the growing period is mostly 3～6 years,usually transplanting after 2～3 years of growth.At present,there is a single variety of transplanting equipment for American ginseng,and most of them are semi-mechanized products,with more manual assistance,low efficiency,high labor intensity,high production cost.Besides,it is not easy to guarantee the quality of operation.Therefore,the design of a transplanting machine with good performance which is also suitable for the agronomic requirements of American ginseng transplanting in China has become a pressing problem to be solved.In this paper,the author designed and produced a roller and groove combination ginseng transplanting machine for seedling placement,taking 2-year-old seedlings as the research object and conducting grading and physical characteristics tests.After the simulation analysis and test,the structure parameters of the roller groove were optimized to achieve the purpose of seedling placement for the mechanized transplanting of American ginseng.The main research contents and conclusions are as follows.(1)Determination of physical characteristics of American ginseng seedlings.The ginseng seedlings were divided into three grades according to size and shape,and the second grade seedlings,which accounted for 69.2% of the seedlings,were tested and studied.The physical properties of seedling mass,diameter,density,stacking angle,moisture content,shear modulus,elastic modulus,Poisson’s ratio,and static friction coefficient,rolling friction coefficient and collision recovery coefficient between seedlings and Plexiglas plates were tested to provide a theoretical basis for the subsequent design of seedling placement device of ginseng transplanting machine.(2)Design and fabrication of the roller groove combination ginseng transplanter.According to the physical characteristics of the selected ginseng seedlings and their agronomic requirements,the structure of the seedling delivery device of the ginseng transplanter was determined: the diameter of the delivery drum was 150 mm and the length was 210mm;four grooves were evenly machined on the drum;three different shapes of trapezoidal grooves,circular grooves and square grooves were designed and produced by 3D printing technology for experimental research;the drum speed 9r/min,12r/min and 15r/min were selected for the experimental study;and the seedling box,seedling cleaning and guiding device were determined according to the stacking angle and friction coefficient of American ginseng seedlings.(3)Simulation analysis of the seedling placement device of the combined roller groove type ginseng transplanting machine.The kinematic and kinetic analysis of the trajectory of the seedlings in the transplanting machine using Adams software showed that the maximum velocity of the seedlings in the transplanting process was 0.9m/s,which occurred at the initial moment when they fell into the seedling delivery drum.The maximum force on the seedling during transplanting is 7N,which occurs when it comes into contact with the elastic lifting plate.The animation trajectory of the seedling transplanting simulation process supports the structural optimization of the transplanter.(4)Experiment and test of seedling placement device of roller groove combination type ginseng transplanter.With the shape of the groove,the speed of the seedling cleaning and guiding roller,and the speed of the seedling delivery roller as the test factors,17 sets of test combinations were measured with the help of response surface model analysis and the software Design-Expert 8.0.6.1 test design program.According to the results of the software,the optimal combinations were: 23.91 r/min for the curved groove,seedling cleaning and guiding device,and 11.52 r/min for the seedling placement roller,and the data were optimized by selecting 24r/min for the curved groove,seedling cleaning and guiding device,and 12 r/min for the seedling placement roller for five replicate tests.The average values of seedling leakage index,seedling injury index and transplanting pass index were 8.20%,4.83% and 85.44%,respectively.The test results were consistent with the optimized results and close to the predicted results of the model,indicating that the combination method based on the response surface model analysis was feasible.In this paper,the author designed and fabricated the seedling placement test device of ginseng transplanting machine for the physical characteristics of ginseng seedlings and the agronomic requirements of transplanting operation,and conducted theoretical analysis and experimental research on its main working parts,which provided the theoretical basis for the development of new ginseng transplanting machine. |
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