油莎豆种子籽粒离散元仿真参数标定与试验

Calibration and Experiments for Discrete Element Simulation Parameters of Cyperus Esculentus Seeds

为了解决新型油料作物油莎豆排种器设计过程中种子物理参数不清及仿真参数与实际差异较大,造成模拟试验不准确,制约油莎豆排种器的发展的问题,测定了油莎豆种子的几何参数、弹性模量、泊松比、摩擦因数、碰撞恢复系数和休止角。以截面圆跳动法测出油莎豆种子精确外形轮廓并建立仿真颗粒模型,通过离散元仿真参数标定得出油莎豆种间静摩擦系数为0.662,油莎豆种间滚动摩擦因数为0.024。通过休止角试验验证,得到误差为1.61%,较标定前降低92.9%。通过排种仿真试验、排种器试验台试验和播种田间试验验证,得到仿真重播指数相对误差为3.79%、4.64%,漏播指数相对误差为6.81%、8.64%。由此表明,油莎豆仿真参数标定值可靠,可为油莎豆单粒精播排种器设计优化提供参考。

The problems of unclear physical parameters of seeds and significant differences between simulated and actual parameters in the design process of seed disperser for new oilseed crops can affect the exact type of simulation tests and restrict the development of seed dispersers for cyperus esculentus.In this study,the geometric parameters,elastic modulus,Poisson's ratio,friction coefficient,collision recovery coefficient and rest angle of the seeds were measured.The detailed profile of the seeds was measured by the cross-sectional beating method,and the simulated particle model was established.The discrete element simulation parameters were calibrated to give a static friction coefficient of 0.662 and a rolling friction coefficient of 0.024,and the rest angle was verified to be 1.61%,92.9%lower than before calibration.The relative errors were 3.79%and 4.64%for the simulated reseeding index and 6.81%and 8.64%for the missed sowing index,as verified by the seeding simulation test,seeder test bench test and sowing field test.The calibration values of the simulated parameters are reliable,providing a reference for optimising the design of a single grain precision sowing seeder for cyperus esculentus.