甘薯收获与秧蔓回收联合作业机的设计与仿真

发布时间：2019-01-28 22:35

【摘要】：我国是甘薯种植面积最大的国家。近些年,甘薯种植户渴望早日实现机械化生产,现有甘薯收获机械主要参考马铃薯收获机械,缺乏针对性。另外秧蔓的处理多采用人工处理,费事费力,虽然出现几款甘薯秧蔓处理机械,功能比较单一。在了解国内外现有甘薯生产机械的基础上,研制一款可同时实现甘薯收获和秧蔓回收的复合机械。主要内容有:(1)总体方案设计。主要由动力及传动系统、履带底盘、秧蔓回收装置、挖掘机构、分离输送机构和集薯、秧箱等组成,利用Solid Works软件对整机三维建模和虚拟装配。(2)甘薯秧蔓力学特性试验。对甘薯秧蔓茎叶和根部分别进行拉伸和剪切试验,得到甘薯茎叶的拉伸负荷和根部的弹性模量,为后续相应部件的设计和仿真提供理论依据。(3)关键部件的设计。对圆盘切割器、立式滚筒拨禾机构、挖掘铲进行受力分析,保证其工作强度符合要求,另外对分离输送器、夹持输送链进行运动学分析保证其输送甘薯块茎和秧蔓的效果最好。在分析的基础上对各部件进行结构设计和三维建模,其中立式滚筒中凸轮的设计采用MATLAB编程提取轮廓曲线上的数据点的方式,保证了凸轮机构的运行精度。(4)对关键部件的运动学、动力学仿真。根据设计参数运用Adams软件对圆盘切割器进行运动学仿真,得到了刀片的运动轨迹,保证了不漏切秧蔓主秧茎,设计了正交试验,对圆盘切割器的参数进行优化;利用EDEM离散元仿真分析软件对薯、土分离过程进行仿真,得到最优运动参数,减小了甘薯破损率;利用Adams软件对立式滚筒拨禾机构进行了动力学仿真,得到了拨禾齿的位移、速度、加速度曲线图,验证了机构的设计合理性。(5)对主要受力部件挖掘铲进行静力学仿真。利用ANSYS对挖掘铲进行了静力仿真保证结构设计的合理性和在作业时安全可靠性。(6)秧蔓回收装置的田间试验。通过试验对甘薯秧蔓除净率、伤薯率、留茬高度、生产率等指标进行考察,验证圆盘切割器和夹持输送链的性能。并通过正交试验得到机器前进速度、刀盘转速、刀盘倾角的最佳参数组合。(7)创新点。设计一款可同时对甘薯块茎收获和秧蔓回收的复合机械,提高了甘薯生成的效率。对拨禾机构进行了创新性设计,解决了秧蔓缠绕拨禾齿的问题。
[Abstract]:Our country is the country with the largest planting area of sweet potato. In recent years, sweet potato growers are eager to realize mechanized production at an early date, and the existing sweet potato harvesting machinery mainly refers to potato harvesting machinery, which lacks pertinence. In addition, the processing of the seedlings more manual, time-consuming, although there are several sweet potato vine processing machinery, the function is relatively simple. On the basis of understanding the existing production machinery of sweet potato at home and abroad, a compound machinery was developed to realize the harvesting of sweet potato and the recovery of seedling vine at the same time. The main contents are as follows: (1) overall scheme design. It is mainly composed of power and transmission system, crawler chassis, seedling vine recovery device, excavating mechanism, separating conveying mechanism and collecting potato, seedling box, etc. The three-dimensional modeling and virtual assembly of the whole machine are carried out by using Solid Works software. (2) Mechanical properties test of sweet potato seedling vine. The tensile load and elastic modulus of the roots and stems of sweet potato seedlings were obtained by tensile and shear tests on the stems, leaves and roots of sweet potato seedlings, which provided the theoretical basis for the design and simulation of the corresponding components. (3) the design of the key components. The mechanical analysis of disc cutter, vertical roller plucking mechanism and excavating shovel is carried out to ensure its working strength meets the requirements. In addition, the kinematics analysis of separating conveyer and gripping conveying chain ensures the best effect of conveying sweet potato tuber and seedling vine. On the basis of analysis, the structural design and 3D modeling of each component are carried out. The design of cam in vertical drum adopts MATLAB programming to extract the data points on the contour curve. The operating accuracy of cam mechanism is guaranteed. (4) Kinematics and dynamics simulation of key components. According to the design parameters, the kinematics simulation of the disc cutter was carried out by using Adams software, the movement track of the blade was obtained, and the main stem of the seedling was not cut out. The orthogonal test was designed to optimize the parameters of the disc cutter. The EDEM discrete element simulation software was used to simulate the separation process of sweet potato and soil, and the optimal motion parameters were obtained, and the breakage rate of sweet potato was reduced. The dynamic simulation is carried out by using Adams software, and the curves of displacement, velocity and acceleration are obtained, which verifies the rationality of the design of the mechanism. (5) static simulation is carried out on the excavating shovel of the main force components. The static simulation of excavating shovel was carried out by using ANSYS to ensure the rationality of structure design and the safety and reliability in operation. (6) Field experiment of seedling vine recovery device. In order to verify the performance of disc cutter and gripping transport chain, the net rate of vine removal, rate of damaged potato, stubble height and productivity of sweet potato seedlings were investigated. Through orthogonal test, the optimum parameters combination of the machine's forward speed, the speed of the cutter head and the inclination angle of the cutter head are obtained. (7) Innovation points. A compound machine was designed to harvest sweet potato tuber and recover seedling and vine at the same time, which improved the efficiency of sweet potato production. The innovative design of the mechanism solves the problem of the twining of the seedling vine and the drawing of the grain teeth.
【学位授予单位】：山东农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S225.71

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