基于穿山甲前足的三七仿生挖掘铲设计与试验

Design and Experiment of Panax notoginseng Bionic Digging Shovel Based on Front Foot of Pangolin

摘要:

针对三七收获作业时挖掘铲存在挖掘阻力大和能耗高等问题，以穿山甲前足爪趾为仿生原型，设计了一款高效减阻仿生挖掘铲。以三七根茎及种植土壤为研究对象，计算得本征物理参数，设置 Bonding 键参数建立三七根茎离散元模型，分析根土黏结机理，利用Hertz-Mindlin with JKR 建立三七根茎-种植土壤离散元复合模型;通过三维扫描获取穿山甲爪趾点云模型，并运用Solidworks建立仿生挖掘铲三维模型，根据爪趾三维模型设计仿生挖掘铲外形结构;对挖掘铲铲尖与铲柄进行力学分析，确定影响作业质量的设计参数;基于EDEM离散元法建立部件-土壤-作物多元仿真模型，以土壤颗粒速度矢量、土壤扰动率及挖掘阻力为评价指标进行仿真试验，得到不同指标的影响规律;通过台架试验验证仿生挖掘铲作业性能，获取仿生挖掘铲和平面挖掘铲平均挖掘阻力分别为1 171.69、1 442.36 N，平均减阻率为18.81%，台架与仿真试验结果基本一致。试验结果表明仿生挖掘铲具有良好减阻降耗特性，仿生结构设计合理，能满足酸性红土条件下三七收获挖掘作业。

Abstract:

Aiming at the problems of high digging resistance and high energy consumption of the digging shovel during the harvesting operation of Panax notoginseng, a high-efficiency drag reducing bionic digging shovel was designed with the toe of the front foot of pangolin as the bionic prototype. Taking Panax notoginseng rhizome and planting soil as research object, the intrinsic physical parameters were calculated, and the bonding key parameters were set to establish the discrete element model of Panax notoginseng rhizome. The root soil bonding mechanism was analyzed, and the discrete element composite model of Panax notoginseng rhizome planting soil was established by Hertz Mindlin with JKR. The point cloud model of pangolin′s claw toe was obtained by three-dimensional scanning, and the threedimensional model of the bionic excavator shovel was established by using Solidworks. The shape and structure of the bionic excavator shovel were designed according to the three-dimensional model of the claw toe. The mechanical analysis of the shovel tip and handle was carried out to determine the design parameters that affected the operation quality. Based on EDEM discrete element method, the component soil crop multiple simulation model was established, and the simulation experiments were carried out with soil particle velocity vector, soil disturbance rate and excavation resistance as evaluation indexes，and the influence laws of different indexes were obtained. The operation performance of the bionic excavator was verified by bench test. The average digging resistance of the bionic excavator and the plane excavator were 1 171.69 N and 1 442.36 N, respectively, and the average drag reduction rate was 18.81%. The bench test results were basically consistent with the simulation test results. The test results showed that the bionic excavator had good characteristics of reducing resistance and consumption, and the bionic structure design was reasonable, which can meet the harvesting and excavation of Panax notoginseng under the condition of acid laterite.