| With the huge development of China economic,the consumer demand of flowers and seedlings has also increase.Seedling transplanting has been one of hard graft.In our country,the suitable machine is only used in digging holes,but not for digging tree which are still mainly dependent on labor.On the other hand,Imported tree planting machines are usually expensive,which resulting that planting machine can not spread in our country.At present,there are few enterprises develop their own tree-planting machines,but due to the limitation of technical conditions,these tree-planting machine generally works in a low efficient condition and cause large consumption.Therefore,the tree planting machine technology in our country needs to be further improved.Based on these situations above,this study aims to reduce the power consumption,enhance the applicability and flexibility of the existing tree planting machine,and focusing on the stress situation in the process during soil cutting by shovel blade,designs a new kind of non-smooth bionic shovel according to the structure of the jaw of ground beetle.Stress state of the swing arm of tree-planting machine is also analyzed and optimal size of arm has been confirmed based on the analyses above.The main content of this paper are as follows:1)Finite element model of shovel and soil were established,after that,the dynamic process of soil cutting was simulated by ANSYS/LS-DYNA to analyze the force of the shovel.When the soil cutoff angle was between 60° to 85°,resistance of the blade was calculated with the step of 1 degree.According to the result of analyze,the optimum soil cutoff angle was confirmed as 83 degree.2)The non-smooth bionic shovel was designed according to the structure of the jaw of ground beetle.Crown-shaped bulge was designed on the surface if the original shovel,and the bionic shovel and soil finite element model were established.Then,simulation calculation was carried out through ANSYS/LS-DYNA using the models above,and the influence of the height,the size and the distance of the protrusion on the force of the blade is studied under the condition of the same soil penetration angle so as to determine the optimal protrusion size and the protrusion pitch.3)Transmission principle and force situation of the arm on tree-planting machine was studied,its kinematics model and the dynamic model were established respectively,instantaneous stress of each hinge point of the arm was solved,finally,the work formula of hydraulic cylinder was listed.4)The study aimed at minimum of working energy and track swing of arm’s terminus towards the way forward,and built a structure parameter optimization model for the arm on tree-planting machine with constraints of component transmission angel requirement and the demand that structure space and working space of arm shouldn’t be interfered.The optimization program is complied by using MATLAB software to calculate the optimized size of each bar of the arm.5)According to the optimized design results,the bionic shovels and arms were fabricated and installed on the tree-planting machine prototype to carry on the excavation test.Result of test found that it has been in good agreement with the simulation results,which proves the rationality of the optimum design we have made in this study. |
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