Motion Synthesis And Design Of Rice Pot Seedling Transplanting Mechanism Based On Constraint Of Output Swing Angle

Rice pot seedling transplanting technology has the advantages of turns green quickly and non-time of seedling,which is one of the most important ways to increase rice yield in the world at present.Transplanting mechanism is an important part to realize mechanization of rice seedling transplanting.The quality of rice seedling transplanting is affected by its transplanting trajectory.With the in-depth study of transplanting theory,the requirements of transplanting agronomy are increasing,and more complex transplanting trajectories posture have been proposed for transplanting mechanism.However,the traditional transplanting configuration of single planetary gear train is difficult to meet the complex trajectory and posture requirements.In recent years,scholars have broken through the limitation of configuration to complete the design of double planetary gear train transplanting mechanism,which achieved the ideal trajectory posture.However,it is difficult to realize the seedling picking and planting action by the existing double planet gear train transplanting mechanism due to the output rotation problem of double planet gear train transplanting mechanism.Therefore,a design method is proposed in this paper to rice seedling transplanting mechanism with double planetary gear train based on output swing angle constraint,which not only realizes complex trajectory posture and transplanting arm picking and planting action,but also has better non-circular gear.The main contents of this paper are as follows:1)The research status of rice pot seedling transplanting mechanism was analyzed and the limitations of existing transplanting mechanism design was summarized in this paper.In order to obtain ideal trajectory posture and good roundness of non-circular gear,the double planet carrier gear train configuration was selected to design rice pot seedling transplanting mechanism.In order to solve the problem of planting action in the existing double planet gear train transplanting mechanism,a design method was proposed in this paper to transplanting mechanism with double planetary carrier gear train based on output swing angle constraint.2)According to the agronomic requirements of rice pot seedling transplanting,the transplanting trajectory was planned and the key positions were determined.The double planetary carrier transplanting mechanism was simplified as a planar open-chain 3R mechanism.The mechanism parameter solving model was established by using the planar linkage motion synthesis method combined with the given output angle constraint to obtain the mechanism parameters which can accurately pass through four key positions and have the correct output angle constraint.3)In view of the difficulties and blindness in the selection of the number of the existing gear train mechanism configuration library suitable for transplanting,a selection method of double planetary carrier gear train transplanting mechanism configuration was proposed to select the most suitable configuration from the gear train mechanism configuration library.The optimum configuration was obtained by the steps of planetary frame number screening,motion law matching and non-circular gear convexity comparison.4)According to the mechanism parameters and the most suitable configuration,the transmission ratio distribution and pitch curve of the non-circular gears were completed.In order to obtain better pitch curve of non-circular gear,the parameters of pitch curve of non-circular gear were optimized by genetic algorithm.5)The structure design of double planetary carrier transplanting mechanism was completed.The consistency between the theoretical trajectory posture and the simulation trajectory posture was compared by the virtual prototype simulation analysis,and the correctness of the theoretical design of the transplanting mechanism was verified.Finally,the processing and assembly of the physical prototype was completed,and the seedling-picking test of the double planet carrier transplanting mechanism was completed on the test bench at 60r/min and 90r/min respectively.The success rate of seedling picking was 91.53% and 87.46% respectively,and the test analysis was completed according to the seedling picking test results.