【作者】 郜楠；

【导师】 李建桥； 崔占荣；

【作者基本信息】 吉林大学 ， 农业机械化工程， 2008， 硕士

【摘要】 本研究结合高校与企业之间的科研项目,分析了中小型水稻割捆机的基本组成、工作机理、发展概况与趋势。通过割捆机打捆试验,确定了影响打捆成功率的主次因素,优水平组合及割捆机打捆机构受力参数;发现打捆机构对割捆机的打捆性能的优劣影响最为重要。受人手打结动作行为特征的启发,利用仿生学原理,着重对割捆机打捆机构进行分析研究。使用三维建模软件Pro/E,基于整机设计中确定的机构尺寸参数,创建了割捆机打捆机构的三维装配模型。将打捆针部件简化为曲柄摇杆四杆机构,进行了四杆机构的动力学分析,确定了四杆机构的设计关系。通过Mech/Pro接口程序,将机构的三维模型导入到机械系统动力学仿真分析软件ADAMS中,对机构进行了限位约束。根据打捆试验中确定的打捆机构受力参数,在ADAMS环境下对打捆针部件进行了动态仿真,获得了相关的运动学及动力学特征曲线。基于上述特征曲线,对打捆针的运动规律进行了研究分析,以寻求出打捆机构合理的铰链点位置。对打捆针部件进行参数化分析,建立设计变量,以曲柄驱动力矩为优化目标,使其绝对值能够最小。在既定目标下对打捆针部件进行优化,得到打捆针部件的最优设计。本论文以Pro/E与ADAMS联合仿真的虚拟样机技术为手段,对中小型水稻割捆机打捆机构动力特性进行分析研究,是现代化数字检测及设计方法的应用。打捆针部件优化的结果,为整个打捆机构的优化提供了重要依据,为割捆机打捆机构和其它农业机械中的类似机构进行更加深入的数字化研究奠定了坚实的基础,对农业机具优化设计研究具有较强的参考意义。更多还原

【Abstract】 The planting area and total production of rice takes about a proportion of 34% and 44% respectively of all crops in China, which means rice is the most dominant foodstuff in terms of planting area and production. Because of climate, planting scale, geometry conditions, there are a lot of regions in China where big-scaled combine harvesters can’t work. If mid-small-scaled rice reaping-binders can be used for indirect harvesting in steps, we could save time for lack of harvest machines. Also, the harvest quality, machine productivity and total rice production can be raised. Harvest reaping-binders are used for reaping and binding crops, for example of rice, and it is to some degree complicated comparing with other mid-small-scaled harvest equipment. It consists of walking parts, power transporting parts, pre-processing parts, reaping parts, crop transporting parts, and binding parts, the property of which is most important to the whole working quality. Enlightened by bionics of the flexible binding process of human fingers, this research focuses on the binding parts study by using virtual prototyping technologies.Firstly the main parts of a rice reaping-binder were designed, including the reapers, the grain lifters, the grain dividers, and the binding parts, which was emphasized for studying. Then all parts were assembled together for drawing. In this process, the property of parts was deeply understood. An orthogonal-supplemental experiment of binding productivity was taken, under the condition of various working transmission of the reaping-binder, various crop qualities, and various binding ropes, in the inside soil bin lab, for measuring the force data on the binding parts. We found that the factors which affect the experiment, in the sequence of importance, are crop qualities, type of binding ropes, and the working transmission of a reaping-binder. An optimized combine of the factors are crop moisture content of 30.1%, transmission of manual operating, original ropes. The factors affect very little the force on binding parts. The fact that binding parts affect a lot the binding parts has been validated. Also, the force data on the binding parts has been acquired, which is an important reference reason for the next step of establishing models.Virtual prototyping technology, which is also called mechanical system dynamic simulation technology, was developed in 1980s. Not only Applying virtual prototyping technologies in developing new production can decrease production costs by saving capital and time, but also increase production’s competence in market. Thereby, studying the application of virtual prototyping technologies in agricultural machinery design, actualizing numeral development of agricultural machinery, can raise the agricultural machinery research level, also can promote the development of agricultural mechanization. By using Pro/E software, 3-D models of binding needle parts and binding nib were established and they were assembled virtually in the Pro/E environment. Afterwards, the binding parts were placed in the 3-D environment under the space limit and all the models were converted into ADAMS from Pro/E by using the interface software Mechanism/Pro. The 3-D models were restricted virtually so that they could be analyzed in motion.The author predigested the binding needle parts into a crank-rod mechanism and its kinemics was analyzed. The design relation of the crank-rod mechanism was confirmed and its motion was simulated in ADAMS environment, so the dynamic and kinetic characteristic was gained. The binding needle parts were analyzed and they were parameterized in the ADAMS environment. Design Variables of locations of the mechanism joints were established and a first optimization of the mechanism under the optimum aim of smallest driving moment was undertaken. Afterwards the sensitivity Design Variables (DV) of this mechanism could be found. Then a second modification of the sensitive DVs was conducted and the crank-rod mechanism was optimized. The most sensitive DVs were confirmed and the optimum combine of DVs was assured. As a result, an optimized location of joints leaded to an optimized mechanism.This work established the 3-D geometric models of the binding parts of a reaping-binder, the dynamics & kinetics characteristics of which has been analyzed by utilizing the Virtual Prototyping Technologies. An optimized location of the binding needle parts under the aim of smallest driving moment on the crank of the parts has been found. The modern digital detection and design method of virtual assembling, motion simulating, and optimizing in the dynamic characteristics research on the mid-small-scaled rice reaping-binder are applications of computer technologies in agricultural & mechanical design, which lays the foundation for ulterior research in the binding parts of reaping-binders and similar mechanisms of other agricultural machines. This paper work has novel reference to the agricultural & mechanical design.更多还原