DESIGN AND EXPERIMENT OF DRAG REDUCTION CHARACTERISTICS OF CASSAVA BIONIC DIGGING SHOVEL BASED ON RED SOI

Aiming at the digging shovel of the red soil harvester in the cassava planting area, problems such as high digging resistance and difficulty in breaking the soil when harvesting cassava tubers will lead to blockage at the connection between the digging device and the transmission device. Using the rabbit's front paws as a bionic prototype, three-dimensional scanning and reverse engineering technologies were employed to extract their unique geometric features. These quantified geometric structural characteristics were then applied to the design of an excavation shovel, aiming to reduce resistance during excavation operations. Based on the discrete element (EDEM) coupled RECURDYN, using the resistance of the excavation shovel and the Bonding key breakage rate as evaluation indicators, the discrete element orthogonal analysis of three factors including the shovel tooth length, shovel tooth width, and shovel edge inclination angle was carried out based on the simulation test results. Test was performed to determine the best parameter combination for drag reduction and crushing rate of the bionic shovel; the working resistance of the shovel was used as an evaluation index to verify the excavation performance of the bionic shovel through field tests. The optimal parameter combination of the bionic shovel based on the discrete element simulation test is the tooth length of 220 mm, the tooth width of 65.1 mm, and the blade inclination 60°. The excavation resistance of this combination is 1733.66 N and the maximum soil fragmentation rate is 92.9%. Through field tests, it can be found that when the excavation depth is 310 mm and the forward speed is 300 mm/s. The Type 1 bionic digging shovel exhibits a reduction in resistance of 6.84%, while the Type 2 bionic digging shovel demonstrates a more significant reduction of 9.21%, compared to the traditional digging shovel. Tests have shown that the bionic shovel type 2 has excellent soil excavation characteristics and can complete cassava excavation operations in tropical red soil areas. It can provide a design reference for reducing drag and saving energy for cassava harvesters.