Design And Optimization Of Potato Pickup Machine

Potato is the fourth food crops following wheat, rice and corn in the world, and it has many advantages such as rich nutrition 、strong adaptability、high yield、wide usage and others. Planting potato in a large scale is of great significance to adjust and optimize the agricultural structure, to increase farmers’ income and our national food security can be ensured. At present, the mechanization of potato production is lower, especially the mechanized harvesting, which still depends on the segmented harvesting method of mechanized mining and spreading, and then artificial pickup. This methods can only realize the half mechanization of potato harvesting, which causes low production efficiency、large labor intensity and high operation cost. Further, it severely restricts the large-scale production of potato in our country, and the mechanization of potato production will be the development direction in the future. After careful review of the the present situation, this thesis finds out the existing problems of the mechanization of potato harvesting in our country and designs a kind of potato pickup machine, which can finish picking up potato,separating potato and clod, transporting and collecting potato at the same time.Using the finite element analysis method to analyse the rack and optimize the structure, it can improve the working reliability of the machine; experimental study is carried out on the prototype and the parametric design system of the pickup shovel is developed. The followings are the completed work and the conclusions :(1) Complete the overall scheme design of the potato pickup machine According to the demand analysis and a variety of schemes comparison, this thesis determines the key components and the overall design scheme of the potato pickup machine.The machine is connected to the tractor by a single point, and it mainly includs potato pickup device, potato and clod separation device, potato hoisting device and potato collection device.The potato pickup device adopts an active form which combines pickup shovel and bar style transmission chain;the potato hoisting device applies the elevator rake installed on the transmission chain,and it can slide up and down in the guide rail, so it can meet the demand of work and transportation;the potato collection device uses hydraulic pressure device to control the height of the mobile bottom and reduce the potato damage.(2) Finish parts structure design, 3D modeling and virtual assembly This thesis uses AutoCAD to complete parts structure design; with the help of Pro/E, the 3D modeling,virtual assembly and dynamic simulation of the parts are finished to avoid parts interference,and it lays the foundation for the finite element analysis.(3) Complete the rack’s finite element analysis and optimization Based on the theory stress analysis of the rack, this research uses ANSYS to carry out the rack’s statics analysis,which draws the results that the maximum stress of the rack is 260.54 MPa, and the maximum deformation is 8.957 mm. According to the results of the finite element analysis on the rack, after optimizing the structure and reselecting the material, the maximum deformation and maximum stress of the optimized rack are 2.773 mm and 136.328 MPa,which can meet the design needs.(4) Make the prototype and the experiment The simulated field experiment and real field experiment are carried out after the main parts design drawings and the prototype production. The simulation results show that the prototype runs stably; the potato and clod thoroughly separate; the average potato pickup rate is 3.9%, and the collection rate is 97.5%,which can meet the national standards and design requirements of the industry. In practical field experiments, the prototype performes well, and basically meets the design requirements.The average rate of potato collection, injury and impurity are 96.5%, 8.8% and 12.8%respectively. The injury and impurity rate are higher than the national industry standards.(5) Parametric design of the pickup shovel The C++ language is taken in the Visual Studio development platform to develop the Pro/E, and then the parametric design of the pickup shovel is completed. It will automatically creat the 3D model and 2D engineering drawings after changing the parameters.