基于EDEM的茶树切割刀片仿真优化设计与试验

Simulation Optimization Design ad Experiment of Tea Tree Cutting Blade Based on EDEM

摘要:

针对茶树修剪过程枝条力学行为复杂和切割工况多变等问题，本文以多年成熟茶树为对象，通过物理试验测定其本征参数、表面接触参数;基于标定参数构建切割装置EDEM仿真模型，以切割角、刀刃角、切割速度3个参数为试验因素，以最大剪切力为试验指标，开展Box-Behnken优化试验。以标定茶树枝条离散元参数开展剪切仿真试验，结果表明，仿真最大剪切力与实测最大剪切力平均值相对误差为2.25%;最优刀片参数组合为切割角16.7°、刀刃角38.8°、切割速度0.43 m/s，利用最优参数组合进行验证，结果表明最大剪切力与回归方程预测值相对误差为1.75%。研究结果可为茶叶收获设备研发提供参考。

Abstract:

In response to the complex mechanical behavior of branches during tea tree pruning and the variable cutting conditions, in order to improve the accuracy and reliability of the discrete element method in guiding the optimization design of the tea branch cutting device, a discrete element model of the aggregate was established, and on this basis, the cutting blade was optimized through the discrete element method (DEM) simulation. Taking mature tea trees as the object, the intrinsic parameters and surface contact parameters of the tea branches were measured through physical experiments. Based on the calibrated parameters, an EDEM simulation model of the cutting device was constructed, focusing on the three core parameters of the cutting angle, the blade angle, and the cutting speed. With the goal of maximum cutting force, Box-Behnken experiments were carried out to optimize the parameters of the cutting blade. A shear simulation experiment was conducted by using the calibrated discrete element parameters of the tea branch, and the relative error between the maximum cutting force obtained and the measured maximum cutting force was 2.25%. The optimal parameter combination of the blade was the cutting angle of 16.7°, the blade angle of 38.8°, and the cutting speed of 0.43 m/s. The EDEM simulation of the optimal parameter combination verified the relative error between the maximum cutting force and the regression equation prediction as 1.75%. The parameter calibration results of the tea branch aggregate discrete element model can provide a reference for tea tree cutting discrete element simulation, and the optimization design results of the cutting blade can be used for the subsequent development of tea harvesting equipment.