蔬菜穴盘苗自动取苗装置的设计与研究

发布时间：2018-01-02 20:22

本文关键词：蔬菜穴盘苗自动取苗装置的设计与研究　出处：《沈阳农业大学》2015年博士论文　论文类型：学位论文

【摘要】：移栽是蔬菜生产过程中的重要一环,目前我国主要依靠人工和半自动机具进行移栽,后者依然需要人工喂苗,效率提升有限,全自动移栽效率高、用工少,是我国蔬菜移栽机械化的发展方向。目前全自动移栽机在我国尚处在研发试验阶段,其中的制约移栽机自动化发展的关键问题就是自动取苗装置的研发。本文在分析了国内外自动取苗先进技术的基础上,结合我国蔬菜种植的实际情况,确定了以机械式顶出-夹取的取苗方式,据此方式研制了穴盘苗自动取苗装置,并对其进行了理论分析、虚拟建模和试验研究。主要的研究结论如下：1.进行了基质苗顶出和夹取钵体力学性能试验,研究得到不同基质含水率、顶杆直径、顶出速度对顶出率的影响；并通过试验建立了128穴番茄基质苗在不同含水率下的抗压力与压缩量的变化曲线。结果表明顶杆直径、基质含水率对顶出率的影响为高度显著,而顶苗速度对顶出率没有显著影响,随着基质含水率的上升、顶杆直径的减小,顶出率会逐渐下降,在含水率为35.09%,顶杆直径为8mm时,顶出率达到100%；在含水率为57.23%,顶杆直径为5mm时,顶出率最低,仅为81.25%。基质块抗压力随压缩量的增加呈加速上升趋势,在压缩量到达12mm时三种含水率下的抗压力分别为48.89N.43.87N、35.85N。2.根据得出的钵体力学特性,建立各个执行机构的数学模型,并对顶苗机构和苗盘输送机构进行运动学和动力学分析。在Microsoft Visual Studio开发环境下,编写了可视化的蔬菜穴盘苗自动取苗装置时序分析程序。对各个机构的动作进行匹配,并进行了参数优化,得到一组最佳参数：纵移机构的初始相位角φz=185°,顶苗机构的初始相位角φd=108°,曲柄长度a=78mm,连杆长度b=112mm,偏心距e=20mm,苗爪翻转机构的初始相位角φf=15°,翻转凸轮的行程为29mm,苗爪开合机构的初始相位角φk=135°。3.利用有限元分析软件,模拟柔性苗爪的工作情况,分析其夹持基质块时的变形情况,得出了在苗爪上端强制位移为2mm、3mm和4mm时,苗爪在基质苗抗压力的作用下各点的位移和von-mises应力云图,证明了柔性苗爪的可行性。利用虚拟样机技术建立了蔬菜自动取苗装置所有零部件的三维模型,并进行了虚拟装配,对取苗机构进行了运动仿真,结果显示蔬菜自动取苗装置设计合理,各个动作符合设计构想,能较好的完成取苗动作。4.试制了蔬菜穴盘苗自动取苗装置样机,进行了性能试验。空盘运行时,在取苗速度低于140株/min时,依然能保持动作平稳有序,在取苗速度提升至接近200株/min时,取苗机械手末端在翻转时出现了较为明显的振动。取苗试验的结果显示,蔬菜穴盘苗自动取苗装置具有较高的取苗成功率,取苗速度为140株/min时的取苗成功率在95%以上,达到我国旱地移栽机对。含水率对取苗成功率和基质损失率有显著影响,基质损失率随含水率的上升而上升,在基质含水率为43.09%时,基质的平均损失量为40%。
[Abstract]:The process of transplanting is an important link in the vegetable production, at present our country mainly depends on manual and semi automatic machine transplanting, the latter still need to improve the efficiency of artificial seedling feeding, automatic transplanting, high efficiency, less labor, is the development direction of vegetable Transplanting Mechanization in China. The automatic transplanting machine is still in the trials in China, the development of automatic transplanting machine control are the key problems of automatic seedling pick-up device is developed. Based on the analysis of the seedling automatic advanced technology at home and abroad, combined with the actual situation of China's vegetable planting, the seedlings from the way to the top - mechanical clamping, accordingly the way the development of the automatic picking seedling seedling device, and has carried on the theoretical analysis, virtual modeling and experimental research. The main conclusions are as follows: 1. the seedling top and clip bowl mechanical performance test, research The different substrate moisture content, the diameter of the push rod, the top speed of the top rate; and the establishment of the change curve was 128 points in Tomato Seedling under different moisture content and compression pressure resistance through experiment. The results showed that the diameter of the push rod, the matrix moisture content on the top rate of high degree significantly the top speed on the top, and seedling rate had no significant effect with increasing soil moisture, reduce the diameter of the push rod, the top rate will gradually decline, when the moisture content is 35.09%, the diameter of the push rod is 8mm, the top rate of 100%; when the moisture content is 57.23%, the diameter of the push rod is 5mm the top, the lowest rate is only 81.25%. matrix block pressure resistance was increased with the increase in compression, compression to 12mm three kinds of moisture under the anti pressure are respectively 48.89N.43.87N, 35.85N.2. according to the mechanical characteristics of the pot body, to establish the mathematical model of each actuating mechanism, and the Kinematics and dynamics analysis of top seedling mechanism and seedling tray conveying mechanism. In the Microsoft Visual Studio development environment, written visualization of vegetable plug seedling automatic pick-up device timing analysis program. By matching on each action, and parameter optimization, get a set of optimal parameters: longitudinal initial phase shift mechanism the angle of z=185 degrees, the initial phase of the top seedling mechanism angle d=108 degrees, the length of the crank connecting rod length of a=78mm, b=112mm, eccentricity e=20mm, initial phase of seedling claw turnover mechanism angle of f=15 degrees, flip cam stroke is 29mm, the initial phase of seedling claw switching mechanism angle of k=135 DEG.3. by using finite element analysis software simulation of flexible work seedling claw, analyze the deformation of the matrix block to clamp, obtained in the seedling claw top forced displacement of 2mm, 3mm and 4mm, von of each point displacement and pressure resistance in seedling seedling claw under the action of -mises stress nephogram, proves the feasibility of flexible seedling claw. Establish the three-dimensional model of automatic seedling pick-up device for all parts of vegetables by using the virtual prototype technology and virtual assembly, the pick-up mechanism motion simulation is carried out, results showed that the vegetable automatic seedling pick-up device has the advantages of reasonable design, each action can better meet the design idea complete the pick-up action.4. trial vegetable plug seedling automatic seedling pick-up device prototype was tested. The empty plate when running in the pick-up speed is lower than 140 /min strains, can still maintain a smooth and orderly movement, in the pick-up speed upgrade to close to 200 strains of /min, the seedling manipulator appears at the end of the vibration the more obvious in turnover. Seedling test results revealed that the vegetable seedling automatic seedling pick-up device has high feeding success rate, seedling rate of 140 strains of /min feeding success rate above 95%, up to China's Dryland The transplanter has a significant effect on the success rate and the loss rate of matrix. The matrix loss rate increases with the increase of water content. When the matrix moisture content is 43.09%, the average loss of matrix is 40%..

【学位授予单位】：沈阳农业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：S223.9

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