Type Synthesis And Design Method Of Transplanting Mechanism With Epicyclic Gear Trains

The transplanting machine is a kind of equipment that transplanting the crops from the seedling tray to the field.The transplanting mechanism is used as a core part of the transplanting machine to replace human hands to complete a series of actions such as clipping,bringing and planting seedling,having the advantage of reducing cost,reducing labor intensity,improving labor efficiency.The transplanting mechanism with epicyclic gear trains(TEGT)is widely used in the field of transplanting because of its high working efficiency and small vibration.Due to the variety of transplanting crops and the diversity of planting patterns,different mechanisms are needed to complete the actions suitable for transplanting specific seedlings.The key to solve this problem is to get rid of the structural limitations of the traditional TEGT,synthesize new mechanism configuration of epicyclic gear trains(EGT),and design the reasonable structure transplanting mechanism with EGT having greater potential in motion trajectory and attitude.In this dissertation,the system design method of TEGT is studied: the method to similarity recognition and isomorphism identification of plane kinematic chain is put forward.The synthesis method of double-color graph of EGT is improved and the transformation from topology graph to functional schematic is realized.The optimization method of TEGT is put forward,and the topological graphs with the transplanting feasibility are screened out.Based on the application background of rice seedling transplanting mechanism requiring spatial trajectory,mechanism selection,parameter optimization,virtual simulation,prototype manufacturing,and experiment verification are completed.The main contents and results of this thesis are as follows:(1)In order to solve the problem of isomorphism identification in the process of configuration synthesis,the method of similarity recognition and isomorphism identification is presented,including identification logic,numbering rules and identification procedures.The single-joint kinematic chains with 10,15,21,28 components are arranged in three different configuration computers to verify the isomorphism identification method respectively.Similarity recognition and isomorphism identification of 8 components contracted graph,42 components single color graph,6 components double-color graph and 28 components multicolor graph are carried out.(2)In order to solve the problem to get the double-color graphs of the EGT quickly and efficiently,the synthesis method is improved in this paper.By adding the screening conditions of the longest binary chain,the single color graph synthesis of EGT based on enumeration of contracted graph is improved.The single-color graphs with 5 elements(5,7)and 6 elements(6,9)of EGT are obtained by computer program.The double-color graphs synthesis of EGT is improved.The identification of pseudo-isomorphic is carried out by the method of similar point recognition and isomorphism identification on the basis of adding the virtual point.The isomerous layered double-color graphs with 5 elements are obtained by computer program.The enumeration of pseudo-isomorphism is presented by extracting characteristic matrix,combining transformation of multiple joints and recombining matrix of gear pairs.According to the design requirements(degree of freedom and number of components),the synthesis of EGT is carried out,and finally the double-color graphs are obtained.(3)During the process of mechanisms synthesis of TEGT,it appears that the feasible functional schematic would be omitted easily conversing from double-color graph to functional schematic by experience.The method generating functional schematic of EGT is put forward: extracting cell circuits,describing code value matrix and obtaining schematic of cell circuits.The schematic of cell circuits are matched based on the cell circuit matrix.The systematic atlas of functional schematic of EGT is completed by coaxial principle and code value matrix.The functional schematics of the 5 component EGT are generated by computer program.(4)In view of the working characteristics of transplanting machinery,the optimizing method of TEGT is presented.The double color graphs with 4,5 and 6 components of EGT are screened by using the function of point as the screening condition.The atlas of EGT that suitable for transplanting is obtained.The discriminant formula of transplanting potential considering the number of gears,planets and layers of the topological graph is put forward.The method of judging the compactness of transplanting mechanism based on the distance matrix value is presented.In this way,the optimizing of TEGT is realized.(5)Based on the application background of rice seedling transplanting mechanism which requiring spatial trajectory,the big loop and straight seedling transplanting mechanism of wide and narrow line Z-shaped rice bowl seedling with double planar shelves(TWNZD)is put forward.The function between the nine optimization objects of the transplanting mechanism and the parameters of the mechanism is established.The optimization software is written,and the mechanism parameters which can realize the ideal trajectory for wide and narrow seedling are obtained.(6)On the basis of obtaining the parameters of the transplanting mechanism,TWNZD is designed,simulated and manufactured.The detection of kinematic characteristics of mechanism(track shape,seedling speed and gesture)is carried out by high-speed camera on the test stand.The results matched the technology index of rice seedling transplanting,that verify the feasibility of selected configuration and the correctness of design method.