基于离散元的菠菜收获机根切铲优化设计与试验  

Optimal Design of Spinach Root-cutting Shovel Based on Discrete Element Method

作　　者：苑进[1,2,3] 李金光 邹亮亮 刘雪美[1,2,3] YUAN Jin;LI Jinguang;ZOU Liangliang;LIU Xuemei(College of Mechanical and Electronic Engineering,Shandong Agricultural University,Taian 271018,China;Shandong Provincial Key Laboratory of Horticultural Machinery and Equipment,Taian 271018,China;Shandong Agricultural Equipment Intelligent Engineering Laboratory,Taian 271018,China)

机构地区：[1]山东农业大学机械与电子工程学院,泰安271018 [2]山东省园艺机械与装备重点实验室,泰安271018 [3]山东省农业装备智能化工程实验室,泰安271018

出　　处：《农业机械学报》2020年第S02期85-98,共14页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家自然科学基金项目(51675317);国家重点研发计划项目(2017YFD07011033)。

摘　　要：针对菠菜收获过程中收获散乱、根切阻力大等问题,从根土复合体特性着手,分析收获过程中菠菜根、土壤与根切铲之间的互作关系,以优化根系聚拢、减少土壤雍堵和降低铲切阻力,提高菠菜切根效率。设计了一种兼具切根与根系聚拢功能的新型根切铲,建立了根切受力模型,对铲刀的关键参数进行计算优化,确定了铲刀滑切角为60°,刃口角为45°;测定了菠菜根的生物力学特性,建立菠菜根柔性体离散元模型,并基于颗粒接触力学模型的本构方程计算出菠菜根的粘结参数,结合土壤模型建立菠菜根土复合体,并对各项参数进行标定;构建了根切铲与根土复合体的铲切过程仿真,明晰根切铲的工作机理,确定影响切根与根系聚拢性能的主要参数。利用响应面法对根切铲各项参数进行优化,确定根切铲的最优设计参数为:铲翼角76°、铲翼长度占比57%、铲槽面积占比40%。田间根切试验表明:根切合格率均值为93.8%,采收率均值为87.2%。本研究可为菠菜收获机根切机构的研制提供理论指导。In order to settle the problems of loose spinach harvesting and large root-cutting resistance,starting from the characteristics of root-soil composite,the interaction between spinach roots,soil and root-cutting shovel in the harvest process was analyzed to optimize root gathering,reduce soil clogging,reduce shovel cutting resistance,and improve spinach root cutting efficiency.Firstly,a new type of root-cutting shovel with both root-cutting and root-gathering functions was designed.A root-cutting force model was established to calculate and optimize the key parameters of the blade.The blade cutting angle was determined as 60°,and the blade angle was 45°;the biomechanical properties of spinach roots were measured,a discrete element model of spinach roots with flexible body was established,and the bonding parameters of spinach roots were calculated based on the constitutive equation of the particle contact model.The spinach root-soil composite was established in combination with the soil model and the parameters of that were calibrated.A cutting simulation process of the root-soil composite with root-cutting shovel was built to clarify the working mechanism of the root-cutting shovel,and the main parameters that affected the performance of root-cutting and root-gathering were determined.The response surface simulation design was used to optimize the parameters of the root-cutting shovel.The optimal design parameters of the root-cutting shovel were determined as follows:blade angle was 76°,blade length ratio was 57%,and shove groove area ratio was 40%.Field spinach harvesting test showed that the root-cutting average rate was 93.8%,and the harvesting average rate was 87.2%.This research can provide theoretical guidance for the development of spinach harvester.

关 键 词：菠菜收获 根切铲 离散元法 根土复合体 设计优化 

分 类 号：S225.92[农业科学—农业机械化工程]