Design And Research On Drag Reduction Of Bionic Digging Shovel Of Cassava Harvester

As an important part of cassava harvester,the resistance and adaptability of digging shovel are the restricting factors affecting the development of cassava industrialization.In this study,the shovel-toothed bionic cassava excavator was designed by using bionic drag reduction theory,bionic design technology,discrete element simulation and soil crushing theory.The drag reduction effect of excavating shovel was studied by simulation analysis and field experiment.The main research contents and conclusions are as follows:In this study,the paw toe of the forefoot of Rattus losea was selected as the bionic prototype.The whole middle section of the toes of the forepaws of Rattus losea was cut by frozen section.Images were collected by means of a normal microscope.MATLAB and ORIGIN software were used to fit the characteristic parameters of toe tip contour.Through the method of single factor experiment,9 kinds of bionic excavators with shovel teeth were designed.The model parameters between soil particles of different depths and the model parameters between soil particles of different depths and the excavated parts were calibrated by the method of combining physical experiment and simulation experiment.The drag reduction effect of the shovel-tooth bionic cassava excavator was compared by using "Hertz-Mindlin Cohesion" with JKR contact model.A wireless test system for dynamic parameters of agricultural machinery was applied.Field experiments were carried out on type 0(prototype digging shovel),type3(number of shovel teeth is 8,tooth width is 50mm),type 5(number of shovel teeth is 10,tooth width is 40mm)and type 7(number of shovel teeth is 12,tooth width is30mm)bionic digging shovel.During the test,the rotation speed of the rear output shaft of the tractor was 540 rpm and the working speed of the machine was 1km/h.The results show that: The measured resistance value of each bionic digging shovel is less than that of the type 0(prototype)digging shovel,and the average resultant level force at three points measured by the cassava harvester equipped with the type 5digging shovel is 31796.85 N.The average level resultant force at three points measured by the cassava harvester with type 0(prototype)excavator shovel was35726.80 N.In this condition,the resistance of the bionic cassava digging shovel type5 was reduced by 11% compared with the cassava digging shovel prototype.The rates of bright potato and broken potato were 97.84% and 4.36% respectively.Under the actual working conditions in the field,the bionic digging shovel with shovel teeth has a better drag reduction effect and a better application prospect.