三七茎叶采收机仿生切割刀片设计与试验

Design and Experiment of Bionic Cutting Blades for Panax notoginseng Stem and Leaf Harvesting Machine

针对传统三七茎叶采收机切割刀片在滑切减阻、刀片刃口锋利性等方面存在明显不足,以切叶蚁上颚结构特征为仿生原型,运用逆向工程技术,提取切叶蚁上颚轮廓曲线,分别基于切叶蚁的切齿齿顶尖锐端和上颚轮廓曲线设计了A、B两种不同的仿生切割刀片;开展了EDEM仿真与台架对比试验,仿真试验结果表明,仿生刀片A、B相较于传统刀片的平均最大剪切力分别降低7.74%和3.07%;台架试验结果表明,仿生刀片A、B相较于传统刀片的平均最大剪切力分别降低8.84%和2.53%,并且仿生刀片A、B在提高三七茎秆横切面平整度方面效果显著;3种刀片仿真试验与台架试验所测得的最大剪切力误差均不大于3.64%,仿真试验结果与实际试验结果基本一致。以刀型、切割倾角、切割速度为试验因素,开展正交试验,确定了较优参数组合为仿生刀片A、切割倾角0°、切割速度400 mm/min。基于较优参数组合开展田间试验,结果显示其对三七茎叶采收平均完整率为97.37%,较传统刀片提升2.01个百分点,平均漏割率为2.64%,较传统刀片降低1.46个百分点,表明以切叶蚁上颚切齿齿顶尖锐端为特征点设计的仿生刀片能够有效提升三七采收机作业性能。

In response to the obvious shortcomings of traditional Panax notoginseng stem and leaf harvesting machine cutting blades in sliding cutting resistance reduction and blade edge sharpness,taking the upper jaw structure characteristics of leaf cutting ants as a biomimetic prototype,reverse engineering technology was used to extract the upper jaw contour curve of leaf cutting ants.Two different bionic cutting blades,A and B,were designed based on the sharp end of the cutting tooth tip and the upper jaw contour curve of leaf cutting ants;EDEM simulation and bench comparison experiments were conducted,and the simulation results showed that the average maximum shear forces of bionic blades A and B were reduced by 7.74%and 3.07%compared with that of traditional blades,respectively.The bench test results showed that the average maximum shear force of bionic blades A and B was reduced by 8.84%and 2.53%compared with that of traditional blades,respectively,and bionic blades A and B had a significant effect on improving the flatness of the transverse cutting surface of Panax notoginseng stem.The maximum shear force errors measured by the three blade simulation tests and bench tests were all not more than 3.64%,and the simulation test results were basically consistent with the actual test results.Using blade shape,cutting angle,and cutting speed as experimental factors,an orthogonal experiment was conducted to determine the optimal parameter combination as bionic blade A,cutting angle 0°,and cutting speed 400 mm/min.Based on the optimal parameter combination,field experiments were conducted,and the results showed that the average intact rate of harvesting Panax notoginseng stems and leaves was 97.37%,which was 2.01 percentage points higher than thta of traditional blades.The average missed cutting rate was 2.64%,which was 1.46 percentage points lower than that of traditional blades.This indicated that the bionic blade designed with the sharp end of the cutting teeth on the upper jaw of the leaf cutting ant can effectively improve the operational performance of the Panax notoginseng harvester.