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

Compared to the traditional blanket seedling transplanting,the pot seedling transplanting has the advantages of non-time of seedling,high survival rate and turns green quickly,and it is the most important way to increase crop yield in the world.Different transplanting objects have different shapes and posture requirements of transplanting trajectory.In recent years,with the rapid development of pot seedling transplanting and the deepening of transplanting requirements,more and more complex transplanting trajectories have been proposed,while the traditional single planet carrier two-stage transmission structures has been difficult to meet the needs.The reciprocating motion characteristics of the connecting rod mechanism have been added to the movement of gear linkage mechanism,thus,it has stronger ability than the traditional gear train mechanism to describe the transplanting trajectory,and can meet the requirements of various crop transplanting movement and trajectory.In this paper,in order to obtain gear linkage mechanisms that can achieve pot seedling transplanting systematically,the method of graph theory was employed combined with function vertices screening to synthesize transplanting mechanisms,and the forward kinematics solution,parameter optimization,structural design simulation and test of the specific transplanting mechanisms were carried out.This paper is divided into the following four parts:1.Combining with the research background of transplanting mechanisms,the shortcomings of traditional single planet carrier two-stage gear train transplanting mechanism was analyzed,the research status of structure synthesis and transplanting mechanisms at home and abroad was discussed,and the structure synthesis of gear linkage transplanting mechanisms was put forward,what's more,the main research parts of this paper were determined.2.Based on the analysis of the gear linkage mechanism,the quantitative relation table of the basic elements was obtained.According to the quantity relation,the adjacency matrix assignment method was employed to synthesize the unlabeled graphs and then labeled graphs.The synthetic results were identified by rigid sub-chain,isomorphism,structural rationality and functional isomorphism,and the drawing program of the labeled graphs was compiled and all the labeled graphs of gear linkage with reasonable structure were obtained.3.According to the structural features of existing pot seedling transplanting mechanism,the screening criteria of 1 degree of freedom(DOF)gear linkage transplanting mechanism were formulated,that is,the selection rules of frame,input and output,and the screening program was compiled to screen the labeled graphs.Finally,the labeled graphs of gear linkage mechanisms which are suitable for transplanting were obtained.4.The optimum selection rules of transplanting mechanism were put forward,and two configurations with double planetary frames were selected for the design and application of transplanting mechanism.The kinematics models of the mechanism were established,and the parameter optimization programs were compiled,and got reasonable parameters in human-machine interaction mode.According to the parameters,the3 D design and simulation of the transplanting mechanisms were carried out,and then the physical prototypes were processed,through high-speed camera to capture the pinch point trajectories,compared the theoretical and experimental trajectories,to verify the feasibility of the comprehensive theory and the rationality of structural design.