Design And Research Of The Pruning System For Harvesting Head

This thesis introduces the development of plantations worldwide,and the history of domestic plantations were also introduced and introduced.The destruction of the ecological environment and the land desertification,which is increasingly attracting public attention are comprehensively analyzed.It puts forward the idea that forest tending and harvesting machinery should be vigorously developed.The purpose and significance of the development of multi-functional joint breeding machine are expounded.The structure and working process of multi-functional joint breeding machine are introduced.The development history and current situation of multi-functional joint breeding machine are introduced.The basic working conditions of the pruning system are analyzed to determine the basic design goals and general parameters.According to the design goal and the determined measurement parameters,the basic mechanism design and key parameters of each execution part are determined according to the principle of mechanical design.The basic parameters of the cutting head are taken as the starting point,the mechanism analysis and some preliminary mechanics are carried out.Analysis,design and selection of key components of the operation of the organization,for the non-standard parts after considering the working conditions and work requirements,the size design,the preliminary design of the two actuators,the application of the Creo Parametric 2.0 to the various components designed A three-dimensional model is built,and the parts are assembled to obtain an assembly for subsequent research and simulation.The working state of the knife is analyzed.Based on this,the objective function for evaluating the mechanical properties of the blade is established.The genetic algorithm is used to obtain the curve of the tool with the largest value.The virtual experiment device is built by SolidWorks and the ANSYS Workbench is imported.In the middle,the experimental parameters are determined by the method of structural analysis.Taking the optimized shape of the knife as the experimental group,the two kinds of knife shapes commonly used in engineering design are used as the control group,and the static analysis is carried out by using the finite element.The three kinds of shapes under the same pressure are obtained,which are 110mm,120mm and 130mm respectively.The deformation of wood of different diameters,the experiment find that the difference between the three shapes of the smaller diameter of the wood is not obvious,but the optimization of the knife to the larger diameter of the wood deformation is significantly smaller than the other shape,in this case the wood The risk of damage is significantly reduced.The results show that the optimized blade shape has less damage to wood of various tree diameters,especially for wood with larger tree diameter.For the operation of the feeding system of the pruning system,the opening and closing mechanism of the feeding system is analyzed,so that in order to optimize the movement trajectory of the two arms when opening and closing,the motion symmetry of the mechanism is determined after the initial rod length parameter is determined.Theoretical numerical analysis is carried out.Through the established mathematical model,the stochastic gradient descent algorithm is applied to adjust the position of each rod length and hinge point,so that the symmetry of the mechanism is optimized.In order to verify the optimization results,the CAD simulation model is built using Creo Parametric 2.0 to calculate and simulate kinematics and dynamics,and whether the motion characteristics can meet the actual working requirements.The simulation results show that after optimizing the structure,the left and right feed sticks are always less than 3°,and the motion symmetry and other motion characteristics can meet the normal production requirements.