Optimization Design And Experiment Of The Suspended Cup Planting Mechanism Of Vegetable Transplanter

Vegetables are rich in various vitamins,minerals,and other nutrients that the human body needs,and are one of the essential foods in daily life.At the same time,vegetables are also the second largest cash crop in China,and the planting area has increased year by year,which has become the pillar and advantageous industry of agricultural and rural economic development.Mechanized vegetable transplanting can better ensure agricultural requirements,improve work efficiency,and alleviate the current situation of labor shortage.At present,in the process of mechanized vegetable transplanting,there are different systems for bowl making,seedling raising,and transplanting.There is a problem of disconnection between agricultural machinery and agronomy,and the structure of the transplanting machinery mainly relies on experience design,most of which do not combine the requirements of verticality and hole formation.There is little research on the changes in the performance of the planter in soil planting.Therefore,based on the agronomic requirements of vegetable transplanting,studying the significant parameter action rules that affect the verticality and hole formation effect,improving the structural design of the transplanting machine’s planter,and optimizing its soil planting parameters,improving the verticality of vegetable bowl seedling transplanting and improving the hole formation effect,has certain research value.This study reviewed the current research status of vegetable transplanting machines both domestically and internationally,and combined with the current agricultural requirements for vegetable transplanting,designed an improved spatial cam eccentric disc hanging cup planting mechanism.Focusing on the research goals of"high verticality""good hole forming effect"and"high planting qualification rate",theoretical analysis,ADAMS-EDEM-ANSYS joint simulation,and field experiments were conducted.The main research contents are as follows:（1）According to the agronomic requirements,the overall structure of the eccentric disc transplanter was determined,the key components were selected and designed,the mathematical model of the soil insertion process of the transplanter was established,the process of transplanting seedlings and dropping seedlings of the transplanter was analyzed in kinematics and dynamics,and based on the zero speed planting theory,the trochoid track shape and the corresponding range of motion characteristic parameters that can achieve zero speed planting were determined,The optimal planting position was determined to be located in the ascending segment of the planting trajectory after passing the lowest point,which established a theoretical basis for subsequent simulation experiments.（2）Taking the soil of rotary tillage experimental field as the research object,the physical and mechanical properties of soil,such as density,water content,percentage of particle size,shear modulus,and stacking angle,were measured.According to the measurement results,the soil soil and soil bucket contact mechanics models were determined.Through the Box Behnken test,the regression model of soil stacking angle was established,and the soil contact parameters were calibrated with the measured stacking angle of 41.36°,The calibration results are:soil soil static friction coefficient 0.41,soil soil rolling friction coefficient 0.09,and JKR surface energy10.36 J·m^-2;We established an ADAMS-EDEM bidirectional coupling simulation model,and obtained the trajectory,displacement,velocity and acceleration curves of the end of the planter suspension cup at the coupling simulation ADAMS control end.We analyzed its motion characteristics.（3）The process of planting into soil was simulated through bidirectional coupling simulation.At the EDEM simulation control end,a virtual simulation experiment on hole formation performance was conducted using planting frequency（f）,planting characteristic parameters（λ）,and planting depth（h）as variables.The influence of different working parameters on soil particle disturbance and hole formation effect was analyzed.Based on the BOX Behnken test method,a three factor,three level,quadratic orthogonal rotation combination experiment was conducted.Determine the optimal working parameter combination through parameter optimization as follows:planting frequency 72 plants/min,soil depth 90 mm,and planting characteristic parametersλ（28）1.4,the corresponding vertical size of the planting hole is 7.49 cm,and the effective planting depth is 8.25 cm.（4）Based on EDEM-ANSYS unidirectional coupling simulation,pre-stressed modal analysis was conducted on the key components of the planting mechanism,and the first six natural frequencies and modal shapes were obtained.Transient dynamic analysis was conducted for the working stability under extreme working conditions,and the maximum stress and strain of the planting device were obtained,verifying the working stability of the planting mechanism;Based on the simulation results,the structural parameters of the planter were optimized.The optimization results were as follows:the thickness of the roller bracket was 3 mm,and the thickness of the hanging cup was 3 mm,ensuring that its strength and stiffness met the working requirements and had a higher safety factor.（5）Based on the optimization results of the structural and motion parameters of the planter,a prototype trial production was conducted.Field validation tests were conducted on the simulation test results,and the results showed that the errors between the measured values of the longitudinal size of the hole opening and the effective planting depth and the simulation values were 5.61%and 4.85%,respectively;Three factors,three levels,quadratic orthogonal rotation combination experiment and analysis of variance of experimental results were conducted for planting verticality.Through parameter optimization,the optimal working parameters were determined:planting frequency f=72 plants/min,planting characteristic parametersλ（28）1.4.Hanging cup seedling placement angleθ=32°,the validation test showed an average upright degree of 86.78°,and the qualified rate of upright degree was 96%;Finally,a full performance test of the entire machine was conducted to verify the various performance indicators specified in the transplanting machine industry standards.The results showed that the coefficient of variation of plant spacing was 2.97%,with a relative error of 3.50%compared to the theoretical plant spacing.The planting qualification rate was greater than 85%,which can achieve the required upright degree of seedlings for zero speed planting and has a good effect on soil penetration and hole formation.