作　　者： ; ; ;

机构地区： 华南农业大学工程学院

出　　处： 《农业机械学报》 2018年第2期93-99,共7页

摘　　要： 水稻播种时芽种含水率高、种芽长度差异大,表现出与其他作物种子不同的物理特性。为减小仿真分析时芽种参数设置不准确而形成的模拟系统误差,本文基于水稻芽种摩擦角的试验与仿真测定,标定出不同含水率下的水稻芽种离散元主要接触参数。通过芽种的摩擦角(两种休止角及滑动摩擦角)离散元仿真试验,建立了芽种-不锈钢板静摩擦因数、芽种-芽种静摩擦因数、芽种-芽种滚动摩擦因数与3个摩擦角之间的三元回归方程。以芽种的3个摩擦角试验结果作为修正指标,对回归方程数值求解,得到当仿真结果与试验结果的拟合误差达到允许范围内的3个主要接触参数。将标定后的参数进行试验验证,分别对不同含水率下的芽种摩擦角的仿真测定与实测结果进行对比分析,相对误差均小于2.75%,表明水稻芽种离散元模型与实际颗粒物料体现出相同的摩擦特性,建立的回归模型满足不同含水率芽种参数的标定要求。对其他5个品种的水稻芽种摩擦角实测值与仿真结果进行对比分析,相对误差均在5.54%以内。该水稻芽种的离散元模型及接触参数可为水稻精密播种装置的动态仿真提供参考。 Rice bud seeds exhibit different physical properties from other crop seeds as high moisture content and large length difference of rice buds. Therefore,it is essential to calibrate the main discrete elements contact parameters of rice bud seeds with different moisture contents,and reduce the simulation system error that caused by inaccurate parameters of rice bud seeds. Three main contact parameters were calibrated,including coefficient of static friction between bud seeds and stainless plate（ X_1）,coefficient of static friction between bud seeds（ X_2） and coefficient of rolling friction between bud seeds（ X_3）,through experimental determination combined with simulation test of rice bud seeds friction angle. Two dynamic repose angles α and β and slipping friction angle γ were formed with three devices,and measured with the software In-Sight Explorer based on image processing technology. Then through discrete element simulation test of bud seeds frictions with EDEM,the ternary regression equation between the three coefficients X_1,X_2 and X_3 and the three friction angles was established. The experimental results of the three frictions were the correction index,and the regression equation was numerically solved to obtain the three main content parameters. The verification test of the calibration parameters showed that the relative error between simulation and experiment results of the bud seeds friction angles with different moisture contents was less than 2. 75%. So the discrete element model of rice bud seeds and the actual particle material reflected the same friction characteristics,and theregression model satisfied the calibration requirements for bud seeds parameters with different moisture contents. Furthermore,the relative error of the other variety rice bud seeds was less than 5. 54%,which indicated that the calibrated discrete element model and contact parameters of the bud seeds can be applied to the dynamic simulation of the precision sowing device.

关 键 词： 芽种 休止角 离散元法 接触参数 标定

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