| Peppers is distributed in 28 provinces of China,accounting for more than 12 percent of the total area of vegetable cultivation,with a total output value of 70 billion yuan,ranking first in the vegetable industry.Sichuan as a major pepper production province,due to planting methods and terrain characteristics,the current pepper harvest is still dominated by manpower,picking methods and harvest efficiency are backward,cost is high.For resolve the above difficulties,a design scheme of small-scale hand-held pepper harvester was put forward,in which the harvesting process includes four steps:picking,transferring,cleaning and collecting.According to the characteristics and process of pepper harvesting designed components structure and the pepper harvester of the three-dimensional virtual prototype.The finite element analysis of the key parts,such as screw rod and frame,provide a theoretical basis for the subsequent structural optimization.The specific contents of the study are as follows:（1）A large number of investigations had been carried out on Sichuan pepper,and the planting patterns,plant parameters,pepper size and physical characteristics of the research objects had been determined,the general structure scheme of Pepper Harvester was designed.（2）Based on the analysis of the common picking mechanisms at home and abroad,and combined with the relevant parameters of pepper,the double helix line type unfurling picking device was designed,the size parameters and installation relations of the helix rod were determined,and the maximum rotation speed of the helix rod was determined to be 600r/min,the picking power is 0.6k W.On the basis of the picking device,the installation space and the actual kinematic parameters,the linear tape transport mechanism was designed and the power was calculated to be 0.014k W.On the basis of the principle of air cleaning,the cleaning mechanism was designed,and the fan is selected by calculating the flow rate.According to the ergonomics and the working environment of the whole machine,the driving power of the rear wheel type walking mechanism was calculated to be 2.03k W.On the basis of the total power of each working part,the type of engine and reducer were determined,the transmission scheme of the whole machine was designed,and the transmission ratio and working parameters of each working part were calculated.According to the parameters of each part,the torque and energy were calculated,the type of electromagnetic clutch and battery are selected,and the control scheme of the whole machine was designed.（3）Based on ANSYS Workbench,the finite element analysis of key parts was carried out.The harmonic response of the helix rod of the picking device was analyzed.The consequence indicated that the max displacement of the screw rod is 9.43×10-4mm,and the maximum equivalent stress is 9.09Pa,which fully meets the application requirements under the conditions of 45 steel,0～400 Hz excitation frequency and 9550N?mm excitation torque.（4）The static stress analysis and prestressed modal analysis method was used to analyze the frame.The results of static stress analysis shown that the maximum deformation is 0.094mm,and the maximum equivalent stress is 59.27MPa,which meets the strength and stiffness requirements of the frame.The results of pre-stressed modal analysis shown that the first order resonance frequency of the model is 37.38Hz,which is close to the actual working vibration frequency of the frame.Then,Based on the first order vibration deformation of the model,the frame structure was optimized.The second solution indicated,First-order frequency is 51.60Hz,which is higher than the actual working frequency of the frame,avoiding resonance.Finally,the application requirements are satisfied. |
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