基于逆向工程的水稻精准模型构建及试验验证

Precise Modeling Method of Rice Based on Reverse Engineering and Test Verification

为了更加切实反映水稻谷粒在介质中的运动及颗粒间的碰撞情况,利用逆向工程技术建立谷粒的精准三维模型。使用三维扫描仪测得饱满籽粒和瘪谷的点云数据,在后处理软件中经过数据处理、曲面重构最终生成质量较好的谷粒三维模型,与实际谷粒误差均小于2%。为了进一步验证基于逆向工程方法所建谷粒模型的准确性,采用离散元素法,将构建的谷粒不同模型导入离散元软件中,进行堆积角的仿真模拟及试验验证。堆积角的对比仿真模拟及试验表明:颗粒模型对堆积角的形成有较大影响,所构建模型模拟得到的堆积角与实际试验结果误差更小(3%以内)。该模型可更好地反映水稻籽粒间的接触碰撞和摩擦运动,为水稻籽粒收获清选过程中的动力学仿真分析提供了一种准确性和实用性更高的模型。

In order to reflect the motion in the medium and the collision of particles between grain and mechanism more conscientiously, precise three-dimensional model of grain is constructed using reverse engineering technique. Using a three-dimensional scanner, point cloud data of plump and blighted grains which were measured were imported in post-processing software, processed and reconstructed curve, lastly high quality three-dimensional model was got. Comparing the three-dimensional model of grain with the actual one, it shows that their size error were less than 2%. In order to further validate the accuracy of grain model with reverse engineering techniques, different models of grain which were constructed simulate the angle of repose using discrete element method. The result of simulation and field test showed that particle model has a great influence on the formation of the angle of repose. The simulation results which used modal con-structed in this paper are smaller than the actual test results （3% or less） . That modal better reflect the contact collision and friction between grains, which provides a more precise and practical model for the dynamic simulation of rice grain harvest.