Design And Experiment Of Transplanting Mechanism Of Modified Elliptical Gear Planetary Gear System For Sweet Potato Seedlings

China is the largest producer of sweet potatoes,and the total output of sweet potatoes accounts for 67%of the world’s total output of sweet potatoes.The mechanization of sweet potatoes transplanting has a relatively important role in improving farmers’income and promoting the development of sweet potato industry.At present,sweet potatoes transplanting mechanisms at home and abroad have problems such as low transplanting efficiency,unstable operation,high price and easy to miss seedlings.Therefore,this paper designs a new sweet potato seedlings transplanting mechanism based on modified elliptical gear planetary gear system,and the research is carried out from four aspects:kinematic modeling and analysis,parameter optimization,virtual simulation and experiments of the transplanting mechanism.The main research contents and results are as follows:（1）The transmission characteristics of the modified ellipse were analyzed;according to the agronomic requirements of sweet potato seedlings transplanting,a new sweet potato seedlings transplanting mechanism with the modified elliptical gear planetary gear system was proposed,and its structural composition and working principle were analyzed,and the kinematic model of the transplanting mechanism was established.（2）According to the design requirements of the transplanting mechanism and the agronomic requirements of sweet potato transplanting,six kinematic numerical optimization objectives were established,and the optimization objectives were described by applying the affiliation function in fuzzy optimization theory;the parameter-guided optimization method was used and based on VB6.0 software has compiled the parameter-guided optimization software of the sweet potato seedlings transplanting mechanism.Using this optimization software,a set of optimal mechanism parameters were obtained:α=25 mm、k=0.268、m_{1 1}=1.29、φ₀=185、δ₀=50、α₀=107.5、S=190 mm.（3）The structural design of the transplanting mechanism of the modified elliptical gear planetary gear system was completed according to the optimized transplanting mechanism parameters;the 3D modeling and virtual assembly of the transplanting mechanism were carried out by Solid Works software and imported into Adams for the simulation tests of the virtual prototype;the post-processing function of the software was used to obtain the movement trajectory of the end point of the seedling clamping claw,and the simulation trajectory was compared with the theoretical trajectory obtained by the parameter-guided optimization software,which verified the correctness of the theoretical model of the transplanting mechanism and the design results.（4）Through the 3D model of the transplanting mechanism,Auto CAD software was used to draw 2D drawings,and the parts were processed,assembled and debugged,build the test bench for the sweet potato transplanting mechanism,and carry out the idling tests of the transplanting mechanism,the actual motion trajectory,picking seedling angle,planting seedling angle and other motion characteristics of the prototype were tested and compared with the corresponding theoretical and simulation results,and the three results were basically consistent.At the same time,the transplanting experiments with seedlings of the transplanting mechanism were carried out.The horizontal distance of the sweet potato seedling into the soil and the vertical distance from the ground were 121.1 mm and51.1 mm respectively,and the size of the transplanting hole was 40.3 mm,and the mechanism speed was 10 r/min,20 r/min,30 r/min,the success rate of sweet potato seedlings transplanting was 94%,90%,82%,respectively.It shows that the transplanting mechanism can meet the requirements of institutional design and agronomic requirements of sweet potato seedlings transplanting,and has practical application value and feasibility.