Analysis And Experiment On The Perturbation Process Of Corn-Soybean Composite Row Seed Population Based On DEM-MBD Coupling

As an important grain,oil and feed crops in our country,the conflict between corn and soybean is prominent.The No.1 central document proposed the zone-type composite planting model of soybean and corn.In this planting model,the lower seed drainer is the key component.However,during the sowing operation,the rack will vibrate due to the installation mode of the seed drainer,the amount of straw on the surface and the flatness of the soil,and the vibration will affect the filling process of the mechanical and pneumatic seed drainer to varying degrees.As a result,the performance of high speed precision seed arrangement decreased,and in this mode,corn and soybean seed arrangement were seeded under the same frame platform,but the adaptability of the two populations of materials to vibration parameters was different.Therefore,this project intends to select spoon-wheel corn seed platter and hole-eye soybean seed platter as the core mechanical seed platter of the same machine.Based on the discrete element method and multi-body dynamics(DEM-MBD)coupling method,the public comfortable vibration parameter interval of corn and soybean seed platter is studied.Specific research contents and conclusions are as follows:(1)Briefly introduce the two kinds of corn and soybean compound planting modes in the Huang-Huai-Hai region,select the typical corn(Zhengdan 958)and soybean(Zhonghuang37)in the region as the experimental varieties,test the material characteristic parameters of the corn and soybean,and then establish the corn and soybean seed models based on the measured material parameters,and complete the preliminary preparation for the numerical simulation.It provides reference basis and boundary conditions for theoretical analysis and virtual simulation test of seed arrangement.(2)Explain the DEM-MBD coupling simulation principle and software selection,and then carry out mathematical analysis of vibration characteristics of corn and soybean strip complex planting drill.On this basis,establish a three-dimensional model of corn and soybean seed planter,analyze the seed planter principle,simplify the simulation model,and then apply constraints and add driving functions to it,providing the prerequisite for obtaining effective simulation results.(3)The results of vibration simulation test of DEM-MBD coupling seed seeder were analyzed.4km/h was selected as the normal forward speed of the machine to simulate seeding conditions.Different vibration frequencies and amplitude were taken as test factors to conduct multi-group simulation tests.The results showed that the optimal frequency range of the spoon-wheel corn seed setter was 5-10 Hz,and the qualified rate reached 95.12%,the replay rate was 1.93%,and the leakage rate was 2.95%.The optimal amplitude range was 1-2mm,and the qualified rate reached 94.55%,the replay rate was 2.31%,and the leakage rate was 3.14%.The optimal vibration frequency interval of the socket type soybean seed separator is 10-15 Hz,and the qualified rate is the highest,reaching 93.25%,the replay rate is 2.36%,and the leakage rate is 4.39%.The optimal amplitude interval is 2-3mm,and the qualified rate is the highest,reaching 93.62%,the replay rate is 4.21%,and the leakage rate is 2.17%.Therefore,in the process of compound planting of jade bean,the common comfortable vibration frequency parameters of the two seed arrangers were 10 hz and the amplitude parameters were 2mm.(4)A vibration test platform was built,and the corn and soybean seed platters were installed on the platform at the same time to carry out the test.The seed platters were compared with the simulation test results.The results of the bench test and the simulation test were basically consistent,which verified the accuracy of the DEM-MBD coupling simulation test.Finally,the results showed that the optimal vibration frequency interval of10 hz and the optimal amplitude interval of 2mm could be taken as the target to optimize the structure of the spoon-wheel type corn seed harvester and maintain the same optimal vibration interval as the socket and eye type soybean seed harvester,so as to improve the seed performance and sowing quality.