移栽水稻幼苗机制和发展外文翻译、中英文翻译、毕业外文文献翻译

原文 2： Development of a mechanism for transplanting rice seedlings Transplanting of seedlings is a labor intensive operation in the cultivation of rice. It is also a skilled job and involves working with a stooping posture in a puddled field. There exists a need to mechanize this operation. For this purpose the design of a mechanism was carried out following the method of analytical synthesis. A planar four-bar linkage with coupler extension was selected as the basic design. The path generated by the mechanism was plotted on a computer screen. By varying the dimensions of various links in the mechanism different paths of output motion of the coupler point were obtained. The potential link dimensions were identified based on the suitability of the path for picking, conveying and planting of seedlings as well as the return motion. A four-row self-propelled transplanter using the above mechanism and an optimized-planting finger was then developed and tested. The machine transplanting system was found to be technically viable. India is predominantly an agricultural country with rice as one of its main food crop. It produces about 80 million tons rice annually, which is about 22% of the world rice production.Culturally, transplanting of young seedlings of 2035 days age in water-inundated field is preferred over direct seeding. The former leads to better yield due to better crop management practices that are possible in a transplanted crop. The operation of transplanting requires large amount of manpower (about 400 man-hour/ha) and the task is very laborious involving working in a stooping posture and moving in muddy field. Hence, this is considered as an activity that needs mechanization. Mechanization of transplanting facilitates mechanization of subsequent activities also in the production of the crop. The machines that are already successful in Japan and Korea could not be adopted in India because of economic cost constraints and due to the prevailing cultural practices of this country. Design of planting mechanisms used in power operated transplanters. Anon. states that most of the planting devices of power operated transplanters can be classified as crank and rocker mechanisms of four-bar linkage. A planting finger, which is a part of the coupler link of the mechanism, separates the seedlings from the seedling tray and places them in the soil. The curve traced by the planting finger may have an influence on the stability of the planted seedlings. The kinematic analysis of the planting mechanisms is considered essential for an understanding of its operation and its further improvements. Design of mechanism Erdman and Sandor state most mechanism tasks require a single input to be transferred to a single output. Therefore, single-degree-of-freedom mechanisms are the forms used most frequently.Shigley states that Grublers criterion is concerned with the numbe r of links in the mechanism and with the numbe r and kinds of kinematic pairs. It can be used for determining the degree of freedom of a mechanism. Erdman and Sandor state that analysis techniques can be used to replace costly and time consuming building and testing of physical prototypes in a trial and error design process. Analysis techniques generally form a basic part of most synthesis methods. Norton states that the four-bar linkage should be among the first solutions to motion control problems to be investigated. The fewest parts that can do the job will usually give the least expensive and most reliable solution. Norton states that the Grashof condition can be used as a very simple relationship, which predicts the behavior of a four-bar linkage, based on the link lengths. Zimmerman states that a four-bar mechanism is physically impossible if one of the links has a length greater than the sum of the other three. Hirschhorn states that in a four-bar linkage distinct types of mechanisms could be obtained by inversion. A crank-rocker mechanism is obtained by fixing one of the two links paired with the shortest link. Paul suggested that NewtonRaphson method could used be used to solve the non-linear equations developed for solving the four-bar linkage position problem. Zimmerman states that one basic mechanism design problem for which the four-bar chain can provide solutions is that of finding a point of the coupler of a four-bar mechanism, which describes a path closely approximating the desired one. In a mechanical transplanter the finger follow a desired path of motion. A planar four-bar linkage with all revolute pairs is chosen, as this is very simple, a mechanism made of that may be E. Vareed Thomas / Mechanism and Machine Theory37 (2002) 395410 397 easy to maintain and may cost less to manufacture. The input motion is applied to the crank so that the motion is continuous and rotary. The output motion follow a suitable path in order to meet the requirements of a transplanter specified below. The mechanism should have one degree of freedom and a coupler point that is capable of making a loop may be incorporated. The planting finger will be attached at the coupler point. The dimensions of four links in the four-bar loop, orientation of the fixed link, length of the coupler extension and orientation angle of the coupler extension are to be decided for the design.Since these values could not be synthesized directly it was decided to examine various trial values for the above parameters and study the suitability of the path generated by such mechanism for the purpose of transplanting. The above parameters were changed systematically using arbitrarily set ranges. During the present investigation around 0.23 million linkage designs were examined. The choices of link dimensions were made following a method of analysis and selection. The link dimensions were varied as stated above. The path of motion of the transplanting finger point was calculated and displayed on a computer screen for every trial value of link dimensions.Initially, link dimensions which met the output motion requirements as stated in Section 2.1 were selected. Details are given in Section 2.4. In order to study the linkage design further and to bring out paths that may be better, small ranges of link dimensions were set around the above selected design values. The path of finger point motion was again examined keeping in mind the requirements stated earlier. Out of several designs, one, which would likely give the best path, was selected. Thus, analysis and selection formed the main strategy in the design procedure. Initially the forward travel speed of the transplanting machine was neglected since this was small in comparison to the speed of the planting finger (Stage 1 of design). The angle of the fixed 398 E. Vareed Thomas / Mechanism and Machine Theory37 (2002) 395410 link was also assumed to be zero. After arriving at an approximate design these values were also varied in Stage 2. Finally, the shape of the coupler extension link was also designed such that it moves without interference with other members of the machine . 作者： Edathiparambil Vareed Thomas 出处： Department of Agricultural & Food Engineering, IIT, Kharagpur 721092,India；Received 29 March 2000； accepted 13 September 2001 译文 2： 移栽水稻幼苗机制和发展 在种植水稻的时候移植苗是一个密集型劳动的操作。它也是一个熟练的工作 ,涉及到使用一个弯腰的姿势。便需要一个需要机械化这 个操作。为此设计一个机制进行分析综合的方法后。一个平面四杆机构连杆与耦合器扩展被选为基本设计。路径生成的机制是绘制在计算机屏幕上。通过改变尺寸的各种链接机制不同的路径的输出运动的耦合器点了。潜在的关联尺寸确定了基于适度性的路径选择、输送和种植的树苗以及返回运动。一列 4行的自行式插秧机使用上述机制和优化种植的手指是那么的开发和测试。这台机器移植系统被发现技术上可行。 印度是一个农业大国 ,水稻是主要粮食作物之一。它每年生产大约 8000万吨大米 ,这是大约是世界水稻生产 22%的。在文化上 ,移栽苗的年轻的年龄 20 - 35天是优于直接播种。前者导致更好的产量，由于更好的作物管理措施 ,有可能在一个移植的作物。移植的操作需要大量的人力 (约 400工时 /公顷 )和任务，是非常艰苦的工作，在一个涉及弯腰的姿势和移动在泥泞的田地。因此 ,这被认为是一个活动 ,需要机械化。机械化移栽机械化促进后续活动也在生产的农作物。机器已经成功的在日本和韩国在印度不能采用 ,因为经济成本约束 ,由于这个国家的主流文化实践。 设计种植机制用于电力移栽机操作 。 不久 ,大多数州的移栽机种植设备操作可以分为曲柄摇杆机制的四连杆机构。一个种植的机构 ,这是一个部 分的耦合器连接的机理 ,分离了幼苗苗盘和将它们在土壤中。曲线跟踪的种植的手指可能有一个影响种植幼苗的稳定性。运动学分析是认为必须为种植机制理解其操作及其进一步的改善。 机制的设计 。 Erdman和桑德尔州大部分问题是需要一个输入机制 ,可以转移到一个输出。因此 ,单自由度机制是最经常使用的形式。 Shigley州 ,Grubler的准则是关于链接的数量在机制和数量和种类的运动副。它可以用于确定自由度的一种机制。Erdman和桑德尔状态 ,分析技术可以用来替代昂贵和耗时的构建和测试物理原型在审判和错误的设计过程。分析 技术通常形成一个基本的部分大多数合成方法。诺顿州 ,四连杆机构应该在第一个解决运动控制问题需要研究。最少的部分 ,可以做这项工作通常会给最便宜、最可靠的解决方案。诺顿州 ,格拉晓夫条件可以作为一个非常简单的关系 ,预测了四连杆机构的行为 ,基于链路长度。齐默尔曼指出 ,一个四杆机构是身体不可能如