【作者】 李建平；

【导师】 赵匀；

【作者基本信息】 浙江大学 ， 农业机械化工程， 2006， 博士

【摘要】 抛秧是种新型的水稻栽植技术，有序抛秧是一种具有一定行距和株距的抛秧方式，具插秧和传统抛秧的优点，有序抛秧机械是国内热门的研究课题。其核心部件，分秧机构是有序抛秧机研究的关键和难点。本课题提出并研究了一种基于气流的振动式有序抛秧分秧新机构，本机构完全不同于现有有序抛秧分秧机构。本课题的研究目的，是通过对分秧机构的各参数对钵苗分秧的影响，建立模型并进行参数选择与优化。本文主要的研究内容和结果如下：1)通过对国内外有序抛秧机的研究，指出现有抛秧机存在分秧机构复杂、作业效率低、需带盘操作，增加了机子的操作空间等问题，提出了一种基于气流的振动式有序抛秧分秧新机构，该机构将振动与气流作用相结合，振动使秧苗在振动板上运动，气流使钵苗保持直立，钵苗自动排序，拨秧轮拨指把钵苗一棵棵地拨离，钵苗顺着导苗管落入田中，完成有序抛秧作业。2)用有限元技术研究了抛秧机振动输送机构的动力学性能，得到机构的各阶频率和相应振型，并进行了模态试验分析，试验结果与仿真数据基本一致，可以利用模态分析对振动输送机构的参数进行优化。3)对钵苗在振动输送板上运动学和动力学进行了分析，并模拟计算和实验验证，证明钵苗运动特征值的模拟计算值与实验值接近，用高速摄影进行瞬时速度的分析，发现钵苗瞬时速度是变化和波动的。钵苗在振动板运动的理论分析与计算方法可用于抛秧机振动输送机构的参数分析与优化计算。4)提出了钵苗自动正位的概念，并对钵苗在振动输送过程中受到钉子阻碍后，其运动学和动力学进行了分析。用高速摄影对单颗钵苗和群体钵苗进行观察分析，证明钵苗在运动过程中受到钉子的阻挡后会自动在惯性力的作用下沿振动方向产生土钵在前的运动，通过合理的机构参数选择，钵苗自动正位是可行的，可使原来杂乱的钵苗自动排序。5)对钵苗在气流作用下的动力学特性进行了理论分析，并用试验验证了钵苗在气流作用下是完全可以直立的，通过对钵苗在气流作用下的特性分析与试验，可以确定钵苗在振动时的合适的气流速度，保证钵苗以一种直立的姿势向前运动，做到有序排列。6)建立了拨指拨秧的力平衡式，在不同拨轮转速情况下，对弧形、水平、倾斜三种形状拨指在无挡条和有接条时的拨苗过程的进行高速摄影观察与分析，发现加挡后钵苗能比较容易地达到土钵在下，叶子在上的钵苗下落效果，而无挡条时，则很难做到，拨轮转速太高，则钵苗易掉落，不能可靠地工作。一般情况下，速度较低时拨秧效果较好。7)建立了钵苗在导苗管运动的方程，并对钵苗的入土深度进行了试验，通过试验发现钵苗落差高度在0.75～1.5 m范围内时，秧苗栽植深度为3～13 mm，可以满足秧苗栽深的农艺要求。8)总结全文并提出进一步研究的设想及方法。更多还原

【Abstract】 Seedling throwing is a new type of seedling planting technology and Ordered seedling throwing which has the advantage of planting and traditional seedling throwing is one of seedling throwing methods with a certain row and column space. Ordered seedling thrower is a hot research topic. As an important part, dividing seedling organization is the key point and difficulty in the research of ordered seedling thrower. In this research a new mechanism of dividing seeding based on acting of airflow and vibration, which is total different with present ordered seedling throwing and dividing mechanism, is put forward. The purpose of this research is to build a model to choose and optimize parameters through the study of the effect of dividing mechanism factors on seedling dividing. The research content and results are as following:1) based on the study of ordered seedling thrower all over the world, pointed out the complexity of current seedling dividing mechanism, low efficiency and big operating space problems because of put seedling tray on the thrower, a new mechanism of dividing seedling based on airflow and vibration is put forward. This new mechanism combines vibration together with airflow. Vibration makes seedlings move forward on vibration board and air makes seedlings stand straight. Then seedlings will arrange their order automatically and rotor claws will throw seedlings one by one to soil. Seedlings fall on ground through direct tubes for seedlings.2) Study the kinetics of vibration transport parts by using method of finite element and got the machine parts natural frequency and vibration model. According to the mode test, the result of test indicated that the datum of the finite element analysis and the test datum were in good agreement. Thus it is possible to optimize the parameters of vibration transport mechanism.3) The kinematics and kinetics of seedlings are analyzed on vibration transport board. Through test, it is proved that the simulation seedlings movement value is similar to the test value. Seedling instantaneous velocity is changeable and fluctuant by the analysis of instantaneous velocity using high speed camera. Theoretic analysis and calculation method of seedlings on vibration board can be used in the vibration transport parts parameter analysis and optimization.4) The concept of seedlings automatic position correction is put forward ,and kinematics and kinetics of seedlings are analyzed when seedlings are blocked by nails on vibration board during the process of vibration transportation. Through test of single seedling, group seedlings and the observation and analysis of high speed camera, it can be proved that seedlings soil bowl will move forward under the force of inertia when they are blocked off by nails on vibration board. Seedlings automatic position correction which orders the disordered seedlings automatically can be realized by appropriate machine parameter choice.5) It is feasible that seedlings stand straight by the theoretic analysis of seedlings kinetics under the force of airflow. By the characteristic analysis and test on seedling, a suitable airflow speed during seedlings vibration can ensure seedlings move toward in the stand-up posture and arrange orderly. 6) The rotor force formula are built. By using high speed camera, the situation of taking seedlings is observed and analyzed nuder having block strip or no block strip at different the claw shape and rotor speed, such as arc shape, level shape and slope shape. It is easy for seedlings to fall down with the effect of soil bowl down and leaf above when there are block strips, while it is difficult to have the same effect without block strips, when the rotors speed is very high, stable work can’t be done. Usually good operation effect can be obtained under the low rotors speed.7) The movement formula of seedlings is built in the guide tube and test the depth of seedlings in the mud. Through the experiment, it can be found that the depth of seedlings in the mud is about 3～13 mm which meet the seedlings plant agriculture requirement when the drop height is 0.75～1.5m.8) In the end, there was a conclusion for the paper, and tentative plans for further research were put forward.更多还原