Research On Structural Synthesis And Application Of Gear Type Transplanting Mechanism Based On Graph Theory

The rice pot seedling transplanting has the advantages of not hurting the seedlings and non-time of seedling.Therefore,the seedling transplanting is an important way to improve the yield of rice.Transplanting mechanism is the core of transplanting machine,which simulates the hands to insert the seeding in the seedling box into the soil.The transplanting trajectory and attitude of transplanting mechanism will affect the quality and yield of planted plant directly.With the development of transplanting theory,the complexity of the transplanting of the agronomic requirements and the operation of the mechanism has been gradually improved,and some complex transplanting trajectories have been put forward.For the complex transplanting track,it is difficult to realize with the single planet carrier two stage transmission structures which have been widely applied.In in order to get the gear train type mechanism which can achieve complex trajectory systematically,topologys suitable for transplanting have been obtained through the structure synthesis and screening,and the specific transplanting mechanism was reverse designed.The main contents of this paper are as follows:1.Firstly,the research background of the gear type transplanting mechanism was been analyzed,and the limitations of single planet carrier transplanting mechanism was been illustrated.Then,the isomorphism identification of topology,structure synthesis and gear type transplanting mechanism were discussed.Then the structure synthesis and screening of topology corresponding to gear train was proposed to obtain new transplanting mechanism and the research content and technical route were determined.2.The method of isomorphism identification of monochrome topology and double color topology was proposed by means of the assignment and reassignment of the points.The principle of judging method,the role of all isomorphic correspondence manners and so on were explained,and the method was expounded by means of examples,and the corresponding program was compiled.The functional isomorphism(non-isomorphism but with identical kinematics)of double color topologys were detected by permutation and combination.3.The structure of the double color topology was analyzed,and the relationship between the number of points and the number of edges of the topology was obtained.The single color topologys was synthesized by the method of inserting points to contracted graphs.Based on single color topologys,the double color topologys were synthesized by the addition of rough edges and the labeling of the letter layer.According to the structure characteristics of transplanting mechanism,the selection standards of double color graph were put forward.Double color graphs suitable for transplanting were obtained by screening.4.A double color graph was selected and the specific transplanting mechanism was reverse designed.According to the selected data points,a transplant trajectory was fitted by cubic non-uniform B-spline curves.And the total transmission ratio curve was obtained through the inverse method of four-bar Redemonstrating.The fitting transplanting trajectory cannot been reverse designed by the existing single planet carrier mechanism,so the double planet carrier mechanism can achieve a more complex trajectory.According to the structure of the transplanting mechanism,the total transmission ratio was divided,and the pitch curve of all gears was obtained.5.According to the design parameters,the three-dimensional model of transplanting mechanism was established by Solidworks,and the model was introduced into the ADAMS through the intermediate format.And the transplanting trajectory of clip tip was obtained after the model was processed.Prototype parts were completed through 3D printing technology.The experiment was carried out after the completion of the assembly.And the trajectory transplanting of clip tip was captured by the camera.The theoretical analysis and the feasibility of structural design were verified by comparing the theoretical trajectory,the trajectory of the virtual simulation and the test trajectory.