Abstract: Aiming to solve the problem that the roots of stalk crops affect soil quality in the field,  the hoe plate of the root excavation equipment was taken as the research object,  and the JKR contact model was used to describe the movement of soil particles when they are in contact with each other. Based on the discrete element method,  the influence of the different speeds (forward speed),  the rotation speed of the hoe plate (the rotational angular velocity of the hoe plate around the turning point),  and the height from the ground (the distance of the knife tip from the ground) were analyzed by EDEM software. Using the maximum resultant force in the hoe plate rotation at 60° in the simulation,  the ternary quadratic linear mathematical model was established based on the BoxBehnken Design response surface analysis method,  which was obtained by ANOVA (P<0.01) that shows the rationality and correctness of the built mathematical model. The mathematical model determines that the speed of 0.41 m/s,  rotational speed of 40°/s,  and offground height of 115 mm, the maximum resultant force on the hoe plate can reach a minimum value of 563.36 N. A field test was carried out in the tobacco planting test plot. The field test results showed that the relative error of the measured force value and simulation force value is 5.1%,  verifying that the simulated soil model conforms to the soil mechanical characteristics and can simulate the soil properties of the test site. The study shows the feasibility of the method and that it can further provide a reference for the optimization design of hoe plates.

Key words: hoe plate, discrete element method, response surface analysis method, parameter optimization

摘要： 针对茎秆农作物根系残留田间影响土质的问题，以根系掘除设备的锄板为研究对象，利用JKR接触模型来描述土壤颗粒间相互接触时的运动情况。基于离散元法，采用EDEM软件分析锄板入土过程中不同速度(整机前进速度)、转动角速度(锄板绕转动点旋转的平均角速度)和离地高度(刀尖距地面的距离)对所受合力的影响，并利用仿真得到锄板从初始位置转到指定角度过程中的最大合力值。基于BoxBehnken Design响应面分析法建立三元二次线性数学模型，由方差分析结果得到该数学模型极为显著(P<0.01)，说明所建数学模型的合理性和正确性。由数学模型确定前进速度0.41 m/s，转动角速度40°/s，离地高度115 mm时，锄板所受最大合力可达到其最小值为563.36 N。在烟草种植试验地进行田间实测试验，结果表明，仿真数据数值与田间试验数值相对误差为5.1%，验证模拟的根土复合体土壤模型基本符合土壤力学特性，能真实模拟该试验地土壤属性。研究表明采用离散元法分析锄板入土作业所受合力的可行性，可进一步为锄板的优化设计提供参考。

关键词: 锄板, 离散元法, 响应面分析法, 参数优化