仿生半圆弧齿顶水田除草刀设计与试验

Design and Experiment of Bionic Semi-circular Arc Tooth Top Paddy Field Weeding Knife

摘要:

水稻是我国的主要粮食作物,杂草严重影响水稻的生长与产量。针对现有水田除草刀入土冲击大、结构稳定性不足等问题,本文围绕除草刀关键部件开展结构设计与参数优化研究。基于犬齿结构仿生原理,构建一种半圆弧齿顶结构除草刀模型,系统分析其结构组成与工作原理,并结合水稻栽培行距及根系分布特征,完成关键结构参数设计。通过建立除草刀运动学模型,确定刀轴转速与前进速度的匹配关系,实现结构参数与作业性能的协同设计。此外,采用离散元软件EDEM构建除草刀-土壤耦合仿真模型,以入土深度、转速与前进速度为试验因素,以除草扭矩和土壤扰动速度为试验指标,以降低功耗为目标进行了三因素三水平正交试验,以考察试验因素对除草刀作业性能的影响规律。结果表明:刀轴转速为主要影响因素,其次为入土深度,前进速度影响较小。综合多指标评分结果表明,入土深度50mm、转速180r/min和前进速度0.7m/s的工况参数组合为最优工况,能在增大作业区域内土壤扰动的同时,减少机械负载。同时,提取不同推进距离下的扰动断面轮廓进行几何对比,验证了仿生齿形结构对土壤扰动行为的优化作用,证明其具有较优的作业性能。

Abstract:

Rice is the main food crop in China, and weeds seriously affect the growth and yield of rice. Aiming at the problems of large impact and insufficient structural stability of the existing paddy field weeding knife, focusing on the structural design and parameter optimization of the key components of the weeding knife, based on the bionic principle of canine tooth structure, a weeding knife model with semi-circular tooth top structure was constructed, and its structural composition and working principle were systematically analyzed. Combined with the row spacing and root distribution characteristics of rice cultivation, the key structural parameters were designed. By establishing the kinematics model of the weeding knife, the matching relationship between the rotation speed of the cutter shaft and the forward speed was determined, and the collaborative design of the structural parameters and the working performance was realized. In addition, the discrete element software EDEM was used to construct the weeding knife-soil coupling simulation model. The three-factor and three-level orthogonal test was carried out to investigate the influence of test factors on the performance of the weeding knife by taking the soil depth, rotation speed and forward speed as the test factors, the weeding torque and soil disturbance speed as the test indexes, and the power consumption as the goal. The results showed that the rotation speed of the cutter shaft was the main influencing factor, followed by the depth of penetration, and the influence of the forward speed was relatively small. The results of comprehensive multi-index scoring showed that the combination of working parameters with soil depth of 50mm, rotation speed of 180r/min and forward speed of 0.7m/s was the optimal working condition, which can increase the soil disturbance in the working area and reduce the mechanical load. At the same time, the contour of the disturbed section under different propulsion distances was extracted for geometric comparison, which verified the optimization effect of the bionic tooth structure on the soil disturbance behavior and proved that it had better operation performance.