Corn and soybean triaxial dimensions.

In response to issues such as high miss-seeding rates and uneven seed grain distribution during the operation of the pendulum-lever camshaft hole seeders under the compound planting mode of corn and soybeans in hilly mountainous areas, a method for optimizing the hole seeders by adjusting movable pendulum-lever angle and the number of cam roller groups is proposed. By analyzing the motion process and mechanism of hole formation of the hole-forming device, it was possible to elucidate the influence of the movable pendulum-lever angle and cam roller group number on the improvement of seeding quality. Based on the DEM-MBD coupled simulation, single-factor simulation experiments were conducted using the hole seeders shaft speed, movable pendulum- lever angle, and cam roller group number as test factors, with the seed grain qualification rate, reseeding rate, and miss-seeding rate as test indicators. A three-factor, three-level orthogonal rotation combination simulation experiment was designed to derive a mathematical model of the relationship between test factors and indicators. Data analysis was performed using Design-Expert 13 soft-ware to optimize the regression model for multiple objectives and obtain the optimal parameter combination. The simulation test results indicate that when the hole seeder shaft speeds were 47.43 r/min and 48.09 r/min, the movable pendulum- lever angles were 100.23° and 101.70°, and the number of rollers in the cam group were 2.81 and 2.95,the qualified rates of corn and soybean seeding were 95.19% and 96.07%. The reseeding rates were 3.58% and 2.35%, while the missed seeding rates were 1.23% and 1.58%. The field test results indicate that under the optimal parameter combination, the relative errors of the qualification rate, the reseeding rate, and the missed seeding rate between the simulation tests and the field tests were 0.4% and 0.13%, 1.17% and 0.36%, and 1.57% and 0.23%. This serves to validate the accuracy of the coupled simulation model, and the research findings can provide theoretical support and a point of reference for the design and performance optimization of pendulum- lever cam-type hole seeders in hilly and mountainous areas.

针对丘陵山区玉米大豆复合种植模式下，摆杆凸轮轴式穴播机（pendulum-lever camshaft hole seeders）作业时存在的漏播率（miss-seeding rate）偏高、籽粒分布不均等问题，本研究提出一种通过调节可动摆杆角度与凸轮滚轮组数量优化穴播机的方法。通过分析成穴装置的运动过程与成穴机理，阐明了可动摆杆角度及凸轮滚轮组数量对播种质量的影响规律。基于离散元法-多体动力学（DEM-MBD）耦合仿真平台，以穴播机主轴转速、可动摆杆角度及凸轮滚轮组数量为试验因素，以籽粒合格率（seed grain qualification rate）、重播率（reseeding rate）与漏播率（miss-seeding rate）为试验指标，开展单因素仿真试验。设计三因素三水平正交旋转组合仿真试验，建立试验因素与评价指标间的数学关联模型。采用Design-Expert 13软件进行数据分析，对多目标回归模型进行优化，得到最优参数组合。仿真试验结果表明：当穴播机主轴转速为47.43 r/min、48.09 r/min，可动摆杆角度为100.23°、101.70°，凸轮滚轮组数量为2.81、2.95时，玉米与大豆的播种合格率分别为95.19%、96.07%，重播率分别为3.58%、2.35%，漏播率分别为1.23%、1.58%。田间试验结果表明：在最优参数组合下，仿真试验与田间试验的玉米、大豆播种合格率相对误差分别为0.4%与0.13%，重播率相对误差分别为1.17%与0.36%，漏播率相对误差分别为1.57%与0.23%，该结果验证了耦合仿真模型的准确性，研究结论可为丘陵山区摆杆凸轮式穴播机的设计与性能优化提供理论支撑与参考依据。