Research On Potato Coupled-bionic Digging And Its Drag Reduction

In the hilly areas of southwest China,the soil is viscous-weight and has high moisture content,and the potato are planted in large ridge and double row with high density,which results in large digging resistance during the operation of traditional potato harvesters.Therefore,it is urgent to solve the problems of insufficient tractor power and increased fuel consumption.This paper is based on coupled-bionic theory,the soil organisms with excellent excavation capabilities was selected,the structure and digging track of potato digging shovel was designed and optimized.The disturbed condition and drag reduction effect of coupled bionic excavation on soil were studied and verified in the experiment.The research methods and results of this thesis provide a theoretical reference for the research on drag reduction of soil cultivation components.Choosing Gryllotalpa orientalis as the object,the information of the front paw of the jaw was extracted,and the structure of the potato digging shovel was designed.Through experimentation,the data of digging was captured,and through image processing,curve fitting and digging motion decomposition,the most effective soil digging behavior to study the ridge digging trajectory of potato digging shovel was selected,the potato coupled bionic digging technology was obtained.Compared with the ordinary digging technology of the fixed digging shovel,the experiment verified that the coupled bionic digging has better drag reduction effect.Looking at the full paper,the main work and features of this paper are as follows:(1)Static bionics of potato digging shovel.The digital image of the profile was obtained by the digital stereomicroscope.The outline of the target image was extracted using MATLAB and discretized into data points.The extracted data points were polynomial curve-fitted six times to obtain the internal and external paws of the palatal toes.The functional expression of the inner and outer contour curves were used to design the upper and lower surfaces of the bionic digging shovel.(2)Dynamic bionics of potato digging shovel.High-speed camera system was used to collect the image of the digging motion of the forepaw in the soil simulation medium,the moving image of forepaw was obtained,and the points were marked in the image.The trajectory of the point was extracted and discretized into data points.After six polynomial curve fittings,the kinematic law of potato bionic digging was obtained.(3)Discrete element simulation in coupled-bionic digging process.The soil particle mechanics model was analyzed.Based on the wet particle contact mechanics model,the discrete element simulation models of coupled bionic digging and ordinary digging were established respectively.The simulation was performed in the EDEM discrete element system and the different shovels in the two excavation techniques were compared.The difference between the disturbance and the resistance of the digging was analysed.The result shows that coupled bionic digging is nearly 32% than ordinary digging in drag reduction.(4)The soil bin test of coupled-bionic digging.The digging shovel and test scheme are designed respectively.By comparing the test of coupled-bionic digging and ordinary digging,digging resistance and energy consumption were analyzed.The results of test proved that coupled-bionic digging has 27.5% reduction in resistance and 9% reduction in energy consumption.