Parameter Optimization Design And Experimental Study Of Variable Differential Gear Train Seedling Planting Mechanism

By 2020,China’s vegetable planting area as high as 21.3 million hectares,annual output of 750 million tons,vegetables have become China’s largest agricultural products;moreover,there are many kinds of vegetables in China,including 200 kinds.Different vegetables have different requirements for transplanting plant spacing,and even the transplanting plant spacing of the same vegetable is different at different times and in different regions.In order to improve the adaptability of seedling transplanting mechanism to different transplanting spacings,a variable differential gear train seedling transplanting mechanism was proposed in this paper.The related theoretical research was carried out,the design of software and mechanism structure was optimized,the simulation analysis of virtual prototype and the processing,assembly and experimental research of physical prototype were carried out.The main research contents of this paper are as follows:(1)Referring to the relevant information,the existing transplanting machines at home and abroad were analyzed,and the types of seedling planting mechanism on the transplanting machine and their advantages and disadvantages were studied.After comparative analysis,it was finally decided to adopt the design scheme of variable differential gear train seedling planting mechanism based on the planetary gear train seedling planting mechanism to adapt to the requirements of different plant spacing of vegetable transplanting.(2)The variable differential gear train mechanism based on accurate position and trajectory control was proposed by combining the rod group and the gear train.According to the given three accurate position points,Burmester curve was established,and the solution domain of the mechanism parameter range was established.The trajectory shape control point was introduced.Finally,the rod group solution domain of the mechanism was constructed,the solution domain was screened,and the optimal solution was obtained.The transmission ratio and the pitch curve of the noncircular gear were calculated.(3)The seedling-planting trajectory of the seedling-planting mechanism was analyzed.The graphical interface design module of MATLAB software was used to complete the design software of the variable differential gear train mechanism.The parameters of the linkage group of a group of variable differential gear train mechanisms were obtained by software optimization.On the basis of this group of parameters,a total of three groups of non-circular gear pitch curves were designed by only changing the coordinate parameters of locus control points,and the adaptability to seedling spacing of 300 mm,400mm and 500 mm was realized respectively,and the optimization results of mechanism parameters were obtained.(4)The structure design and three-dimensional model construction of the variable differential gear train seedling planting mechanism were carried out.The interference inspection of the virtual prototype was carried out,and the rationality of its structure was preliminarily judged.The simulation software ADAMS was used to carry out the simulation test on the variable differential gear train seedling planting mechanism,and the simulation trajectory was compared with the theoretical trajectory.The processing of the physical prototype and the construction of the seedling test bench were carried out.The air-rotating physical prototype test was carried out,and the test images were processed.The experimental results and theoretical results were compared and analyzed.The actual seedling planting test was carried out,and the statistical analysis of seedling planting results verified the correctness of the design of variable differential gear train seedling planting mechanism.