Research On Key Technologies Of Sorghum Precision Seeder For Wine Productio

Sorghum is an important cereal crop in China,and its planting area and total output are second only to wheat,rice and corn.In recent years,with the vigorous development of Maotai-flavor liquor industry in Guizhou,the planting area of sorghum for wine has been expanding continuously.At present,the mechanized planting of sorghum for wine has been applied in the aspects of tilling,land preparation,field management and harvest,etc.,but there are still shortcomings in the mechanized planting of sorghum,mainly artificial drilling and broadcast sowing.General purpose small seed seeder has been introduced in some planting areas of Guizhou province,but the quality of operation is not high,and it is difficult to meet the requirements of precision sowing of sorghum for wine.In order to improve the quality of mechanical sowing of sorghum for wine,increase the single grain rate of seed feeder and reduce the recharge rate and leakage rate,theoretical analysis,EDEM simulation test and physical test were used in this paper.The research work of sorghum seed material characteristic measurement,EDEM simulation parameter calibration,precision seed dispenser structure design and optimization,filling theory analysis,filling performance simulation test and bench test were carried out.The main research results of this paper are as follows:(1)The material characteristics of "Maoliangnuo 2" sorghum seeds have been determined.Taking "Maoliangnuo 2" sorghum seeds as the research object,the threedimensional dimensions,thousand-grain weight,bulk density,density,and moisture content of the seeds were measured.A specialized universal testing machine for crops was used to perform compression tests on the sorghum seeds,and the Poisson’s ratio,elastic modulus,and shear modulus of the seeds were measured.A test rig was set up to conduct physical experiments and measure the collision restitution coefficient,static friction coefficient,and rolling friction coefficient of sorghum seeds with different materials(nylon,ABS,65Mn).The angle of repose of the sorghum seeds was measured using the cylinder lifting method.The research results mentioned above can provide data support for the establishment of discrete element simulation parameter models for sorghum seeds and the design and optimization of seeders’ structures.(2)A discrete element simulation parameter model for "Maoliangnuo 2" sorghum seeds has been established.Reverse engineering techniques were employed to create a three-dimensional model of the "Maoliangnuo 2" sorghum seeds.By combining the experimental tests on the test rig with simulation experiments,the simulation contact parameters between the sorghum seeds and the seeder materials were first calibrated.Using the Box-Behnken method,experiments were designed to optimize the maximum measured horizontal rolling distance.The collision restitution coefficient,static friction coefficient,and rolling friction coefficient between the sorghum seeds and nylon(ABS,65Mn)plates were determined to be 0.44,0.45,0.065(0.41,0.46,0.054;0.52,0.57,0.072)respectively.Subsequently,the simulation parameters for the sorghum seeds themselves were calibrated,with the measured angle of repose as the optimization target.The collision restitution coefficient,static friction coefficient,and rolling friction coefficient among the sorghum seed particles were determined to be 0.422,0.504,0.074 respectively.(3)The structural design and theoretical analysis of the nest wheel-type seeder have been completed.Based on the agronomic requirements for liquor sorghum cultivation in Guizhou Province and the material characteristics of the seeds,a precision nest wheel seeder was designed,and its working principle was elucidated.The seed filling process of the seeder was analyzed,and it was proposed to increase the seeding groove to improve the filling performance of the nest wheel.The key component parameters of the nest wheel-type seeder were analyzed and designed,and the preliminary determination was made for the nest wheel diameter,mold hole dimensions(length,width,depth),seeding groove structure,and number of mold holes.Through the analysis of the filling process,it was determined that the maximum speed of the nest wheel should be less than or equal to 125.4 rpm.(4)The filling performance of the seeder was investigated through EDEM simulation experiments and bench-scale tests.Initially,single-factor simulation experiments were conducted to determine the optimal values for the number of mold holes,seeding groove inclination angle,and nest wheel speed,which were found to be 7,30 °,and 20-80 rpm,respectively.Subsequently,based on quadratic regression orthogonal rotation combination simulation experiments,the optimal values for mold hole length,mold hole depth,and nest wheel speed were obtained as 4.84 mm,3.10 mm,and 38.13 rpm,respectively,resulting in a single grain rate of 90.06%.Finally,based on the optimal results from the simulation,a nest wheel was 3D printed and a small-scale seeding test system was constructed to carry out bench-scale tests on the filling performance.The drainage effect of the seeding groove was validated,and the filling single grain rate,re-filling rate,and leakage rate of the nest wheel with the seeding groove were determined as 89.94%,9.55%,and 0.51%,respectively.The relative error between the bench-scale test results and the simulation-optimized single grain rate of90.06% was 0.13%,validating the effectiveness and reliability of the simulation experiments.The research findings of this thesis have theoretical and practical significance in enhancing the design capabilities and research level of precision seeders for liquor sorghum,improving the theory of precision seeding for small-seed grains,and promoting the healthy development of the liquor sorghum industry in Guizhou Province.