Authors

Abstract

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.

Abstract in English

针对木薯种植区域的红土壤收获机挖掘铲在进行收获木薯块茎时挖掘阻力大、土壤破碎困难等问题会导致挖掘装置与传输装置连接处出现堵塞情况，以兔子的前爪为仿生原型，采用三维扫描和逆向工程技术提取其独特的几何特征。然后将这些量化的几何结构特征应用于挖掘铲的设计，旨在减少挖掘作业期间的阻力。基于离散元（EDEM）耦合RECURDYN，以挖掘铲所受阻力、Bonding键破碎率为评价指标，基于仿真试验结果进行了铲齿长度、铲齿宽度、铲刃倾角等3个因素的离散元正交试验,确定仿生铲的减阻的和破碎率最佳的参数组合；通过田间试验以挖掘铲所受工作阻力为评价指标验证仿生挖掘铲的挖掘性能。基于离散元仿真试验可得的仿生铲最佳参数组合为铲齿长度220mm、铲齿宽度65.1mm、铲刃倾角60°，该组合的挖掘阻力为1733.66N和较大的土壤破碎率为92.9%。通过田间试验可得挖掘深度为310mm、前进速为300mm/s时，试验表明仿生铲2型有优秀的土壤挖掘特性，能在热带红土壤地区完成木薯挖掘作业，能为木薯收获机减阻节能做出设计参考。