| The research status of mulch film collector is analyzed in this paper.For the problems of tobacco mulch film collector in the seedling stage such as low recovery rate,film leakage and incomplete mulch film collection,a design thought of mulch film collector in the tobacco seedling stage is proposed.The model machine scheme is confirmed through calculating and designing complete machine transmission and key components of film uncovering operation as well as conducting kinematics analysis and finite element optimization analysis of critical components such as film cutting knife,mulch film shovel and rack.Through systematical field experiments of model machine,the optimal operation parameters of mulch film collector in the tobacco seedling stage are gained.The following researches are mainly conducted in this paper:1.Through analyzing working conditions in the film uncovering process,simulated analysis was conducted for film picking process with Matlab and Ansys transient dynamics to confirm the optimal motion track curve.Besides,the theory of kinematics was used to carry out kinematics analysis of the major component of collector – film picking tooth,and the kinematic model of film picking tooth in the motion process was established.The motion track of mulch film was analyzed to optimize the arrangement mode of film picking tooth when the installation angles of film picking tooth were 30°,60° and 100°respectively.2.The 3D model of the rack was established on the basis of Solidworks software,and Ansys was adopted to solve static stress and modality.On this basis,the cloud chart of inherent frequency and vibration mode variation of the first 6 orders of the rack was obtained.The fatigue life of the rack was calculated by combining external excitation frequency analysis,S-N curve of rack structure and fatigue sensitivity curve.It is found that,the maximum stress value is 140.36 MPa,and the minimum stress value is 3.74 MPa after the increase and decrease of vibration pieces.The fatigue life of the rack is1.1314×106.Under the condition of meeting strength requirement,topological optimization was conducted for the rack by combining static stress analysis result and applying finite element Beta.After topological optimization,the rigidity of X,Y and Z axis of the rack changed little.Moreover,light design scheme of the rack was obtained in combination of multi-goal driven optimization,which improved the working performanceof the structure.Based on the stress analysis of film cutting knife and finite element goal optimization method,the following conclusion is drawn: under the condition of meeting the allowable stress,when high-speed alloy steel with the thickness of 0.9mm is chosen as the material of film cutting knife,non-elastic deformation will not happen,and maximum deformation is 0.000402 mm,which satisfies working requirements.Furthermore,EDEM was applied to verify the power correctness of mulch film shovel.3.The test platform and model machine are processed,and field experiments were done.The orthogonal experiment and Design-Expert optimization experiment were conducted respectively for the operating speed of the machine,depth of mulch film shovel in the soil,and installation angle of film picking tooth.The results show that,mulch film recovery rate is maximum under the following conditions: operating speed 0.3m/s,depth of mulch film shovel in the soil 0.04 m,installation angle of film picking tooth 90°.The operating speed of the machine has significant influence on recovery rate of mulch film collector in the seedling stage. |
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