基于鼹鼠爪趾仿生的茶园旋耕刀减阻设计与试验

Design and Experiment of Bionic Drag-reducing Rotary Blade for Tea Gardens Based on Mole Claw Toes

摘要:

针对南方丘陵山地茶园旋耕整地作业阻力大、能耗高等问题,基于仿生鼹鼠前足物理特征对丘陵山区茶园旋耕刀进行减阻设计。利用逆向工程技术提取了鼹鼠前足中间3个趾(第2、3、4趾)的尖端轮廓和侧向轮廓特征,运用高斯方程和五阶多项式方程进行曲线拟合(决定系数大于等于0.998 6,误差平方和小于等于0. 008 5),进行楔形简化处理和齿形排布优化。根据拟合结果设计了3种仿生齿形旋耕刀(A、B、C型),在EDEM 2023离散元软件上建立了刀具-土壤互作仿真试验模型,得出不同参数条件下传统刀具和3种仿生刀具的平均扭矩和碎土率。并结合台架和田间试验进行了多工况性能验证,试验中前进速度为0.5m/s,旋耕深度为120mm,刀轴转速分别设置为150、200、250r/min。仿真结果表明,3种仿生刀具相较于传统刀具平均扭矩分别降低6.40%、3.73%、5.08% ,碎土率分别提升7.09、8.82、4.68个百分点,其中A型刀具减阻效果最优,B型刀具碎土性能最佳。台架试验结果表明,3种仿生刀具相较于传统刀具平均扭矩分别降低7.25%、4.01%、5.49%。田间试验结果表明仿生刀具A、B、C平均碎土率分别为91.68%、92.84%、89.86% ,相较于传统刀具碎土率分别提升了5.39、6.55、3.57个百分点。

Abstract:

Aiming to address the issues of high resistance and energy consumption during rotary tillage in tea gardens of southern hilly and mountainous areas, a drag-reducing design for a ditching blade was developed based on the bionic physical characteristics of mole forefeet. Reverse engineering technology was employed to extract the tip and lateral contour features of the middle three toes (the 2nd, 3rd, and 4th toes) of the mole forefoot. Gaussian equation and the fifth-order polynomial equation were used for curve fitting (R2≥0.9986, SSE≤0.0085), followed by wedge simplification and tooth arrangement optimization. Based on the fitting results, three types of bionic toothed rotary blades (types A, B, and C) were designed. A tool-soil interaction simulation model was established in the EDEM 2023 discrete element software, and the average torque and soil fragmentation rate of the conventional blade and the three bionic rotary tiller blades under different parameter conditions were obtained. Multi-condition performance verification was further carried out via bench tests and field experiments, in which the forward speed was 0.5m/s, the rotary tillage depth was 120mm, and the blade shaft rotational speeds were set to be 150r/min, 200r/min, and 250r/min, respectively. Simulation results showed that the average torques of the three bionic rotary tiller were reduced by 6.40% , 3.73% and 5.08% compared with that of the conventional rotary tiller blade, and the soil breaking rates were increased by 7.09, 8.82 and 4.68 percentage points, respectively. The optimal drag reduction performance was obtained for type A bionic rotary tiller blade, and the best soil crushing capacity was achieved by type B bionic rotary tiller blade. Bench test results indicated that the average torques of the three bionic rotary tiller blades were decreased by 7.25% , 4.01% and 5.49% in comparison with the traditional cutter. Field test results demonstrated that the average soil breaking rates of bionic rotary tiller blades A, B and C were measured as 91.68% , 92.84% and 89.86% , which were improved by 5.39, 6.55 and 3.57 percentage points relative to that of the traditional cutter.