外文翻译--机电一体化的做法

机电一体化的做法机电一体化的做法1 数控机床科普知识数字控制机床是用数字代码形式的信息(程序指令)，控制刀具按给定的工作程序、运动速度和轨迹进行自动加工的机床，简称数控机床。数控机床具有广泛的适应性，加工对象改变时只需要改变输入的程序指令；加工性能比一般自动机床高，可以精确加工复杂型面，因而适合于加工中小批量、改型频繁、精度要求高、形状又较复杂的工件，并能获得良好的经济效果。随着数控技术的发展，采用数控系统的机床品种日益增多，有车床、铣床、镗床、钻床、磨床、齿轮加工机床和电火花加工机床等。此外还有能自动换刀、一次装卡进行多工序加工的加工中心、车削中心等。1948年，美国帕森斯公司接受美国空军委托，研制飞机螺旋桨叶片轮廓样板的加工设备。由于样板形状复杂多样，精度要求高，一般加工设备难以适应，于是提出计算机控制机床的设想。1949年，该公司在美国麻省理工学院伺服机构研究室的协助下，开始数控机床研究，并于1952年试制成功第一台由大型立式仿形铣床改装而成的三坐标数控铣床，不久即开始正式生产。当时的数控装置采用电子管元件，体积庞大，价格昂贵，只在航空工业等少数有特殊需要的部门用来加工复杂型面零件；1959年，制成了晶体管元件和印刷电路板，使数控装置进入了第二代，体积缩小，成本有所下降；1960年以后，较为简单和经济的点位控制数控钻床，和直线控制数控铣床得到较快发展，使数控机床在机械制造业各部门逐步获得推广。为了保证机床具有很大的工艺适应性能和连续稳定工作的能力，数控机床结构设计的特点是具有足够的刚度、精度、抗振性、热稳定性和精度保持性。进给系统的机械传动链采用滚珠丝杠、静压丝杠和无间隙齿轮副等，以尽量减小反向间隙。机床采用塑料减摩导轨、滚动导轨或静压导轨，以提高运动的平稳性并使低速运动时不出现爬行现象。由于采用了宽调速的进给伺服电动机和宽调速的主轴电动机，可以不用或少用齿轮传动和齿轮变速，这就简化了机床的传动机构。机床布局便于排屑和工件装卸，部分数控机床带有自动排屑器和自动工件交换装置。大部分数控机床采用具有微处理器的可编程序控制器，以代替强电柜中大量的继电器，提高了机床强电控制的可靠性和灵活性。随着微电子技术、计算机技术和软件技术的迅速发展，数控机床的控制系统日益趋向于小型化和多功能化，具备完善的自诊断功能；可靠性也大大提高；数控系统本身将普遍实现自动编程。未来数控机床的类型将更加多样化，多工序集中加工的数控机床品种越来越多；激光加工等技术将应用在切削加工机床上，从而扩大多工序集中的工艺范围；数控机床的自动化程度更加提高，并具有多种监控功能，从而形成一个柔性制造单元，更加便于纳入高度自动化的柔性制造系统中。众所周知，一部机器的基本构成包括原动机、传动部分、执行部分和控制部分。其中传动部分是绝大多数机器不可缺少的重要组成部分。从原动机到工作机部分的变速、改变运动方向、改变运动方式、动力与运动的传递分配等等功能。都是由传动装置完成的。在一些机器中(如机床、汽车)中传动装置占整机的大部分，所以机器的工作性能和运转费用在很大程度上取决于传动部分(传动装置)的优劣。因此，为了适应市场对机械产品的要求，提高传动装置的设计水平具有重要的意义。长期以来，我国在设计机械产品时，一般沿用传统的设计方法，机械产品的设计是一个病态结构的、反复迭代的复杂过程，耗费设计者大量的时间和精力，因此，无论从设计性能和设计速度上均远远满足不了用户的要求，形成了先进产品要求与落后的设计方法上的矛盾。同时，市场竞争的加剧，亦要求产品朝着高质量、低成本、短周期的方向发展RI。目前，机械中常用传动的设计方法常用理论设计法。它是根据现有的科学技术理论及实践知识而进行的设计，所以，常用的设计计算公式多是在某些假设的条件下进行理论推导，再引入一系列的修正系数，而得到的半理论半经验公式。利用这些公式手算时，需要查一系列的有关表格或线图来确定修正系数和某些参数，过程烦琐费时:尤其是机械设计是一个不断修改、不断完善的过程。无数事实证明，富有经验的优秀设计师往往能比刚出校门、同样富有才华的设计师以较快的速度设计出较好的产品来。专家系统技术能帮助我们实现专家设计经验的归纳和利用，使经验的继承和发展大大超越了“师徒之间”的时空限制，从而大大推进了设计质量和效率的提高，因而为使传动的设计适应于产品的市场需求，开发机械传动设计专家系统，使传动设计速度快、计算准确、方案优化成为必然的趋势。2 介绍 在这个文件中，机电一体化采取的是为端铣操作数控铣床制定一个数学模型，并模拟其行为。数学模型的伺服电机控制XY工作台。其它方面的发展是同提出的为端铣操作的模型整合在一起，MATLAB是用来模拟仿真的。实验的初衷是建立在XY工作台上履行铣削操作。仿真的结果验证了实验结果。这样的数学模型可用于评价一个新的设计。因此，一个新的设计在市场上将导致时间和成本大幅度减少。日本在20世纪80年代已经介绍了机电一体化技术是一个概念，尽管人民提及任何系统都具有机械、电气、电子元件等，例如洗衣机、复印机、数控机床等，都具有机电一体化系统，是一种真正的机电一体化设计原理。在传统的设计方法中，系统的组成部分都有各自的专家来完成。例如：一名机械工程师设计机械部分，而电机工程师则设计电器元件等等。因为每个设计师都有一定的安全因素要取决于其它无知的领域的合作，从而使整体的价格变大，且系统变得庞大和昂贵。在机电一体化的设计方法中，整个系统被认为要顾及到各个部件，无论是机械、电气、还是电子设备。由于整体的安全因素小了，因此，该系统的设计尺寸和费用减少了。在这个文件中，机电控制的方法以研究数控机床为主，在援助过程中新设计了一种数控机床就座。这项研究需要模型的加工过程。数控端铣的特点在于以正规的序列个别消减，相当于每齿的接触。这些消减多次强烈重叠。都是为了预知这些瞬时切削力、机械理论的运用等。在不同刀具的切削点，该力模型的发展需要工作台中的表和刀具作为输入参数，并给出了瞬时力作为输出。机械传动元件中组成XY工作台的电机轴和滚珠丝杠也要考虑在内。在这个数学模型中，在机械零件的精度方面，由于刚度力学起着重要的作用，因此，他们也在考虑之列。而该模型中XY工作台的伺服电机则来自于Kataria 和Mehta。靠着这些模型，MATLAB被用于模拟仿真。机床操作中的附件也需要设计和制作，它们附着在已有的XY工作台上来验证实验的仿真结果。3 实验初步成立 在数控铣床的研究中提出的假定是必须做的。在我们的研究中端铣通过一个可用的XY工作台来实现。所以一个框架的设计和制作要能够支持马达和主轴。图1显示了在试验中帧的设计和制作。图2用相片显示了一套完整的模型。附件中的主轴以这样的一种方式来设计，其一端与交流感应电机轴连接，并由其带动旋转，而另一端连接在修饰铣刀用的钻夹头上。其它组件下次解释。3.0 主轴电机在生产技术手册中，动力所要求的端铣都做了，通过一个高速钢刀具动力来切削铝，主轴电机选定为：220伏特，每分钟1440转、250瓦特、单三相交流感应电动机。3.1 帧在立铣结构中，其横向连接如图1所示，是起决定性作用的，因为在切削过程中它消减了对电机和主轴的弯曲应力。这个环节被设计为简支梁，其横截面选定为：35毫米*35毫米，3毫米厚，空心。3.2 刀具夹紧装置在实际的数控机床中，设计条状机械装置是为了保证刀具。不过为了确保系统简单，在这里钻孔卡盘的改装是为了持有刀具。3.3 轴承轴承安装于车架上是为了来固定主轴的，来自于主轴上的力主要是弯曲。所以轴承承受径向力。因此，SKF公司主要选定深沟球轴承60043.4 单片机该系统的反应是通过观察单片机上所用的软件来实现的，而另一个DMC软件是用来沟通控制器卡的。DMC1822是一所两轴控制器用来控制发动机沿X轴和Y轴运动的，无论是软件还是操作工，在多组脉冲作用下均显示错误结果。电机转速和转矩的百分比由电动机在任何时间供给。位置误差在这里按定义之间的不同来进行编辑并取得一定位置。4 系统模型数学模型的完整建立是由组成伺服控制的XY工作台、切削条件等等。也是本节所要介绍的。XY工作台是由装有PCI插槽的电脑控制的，它的所有的计算需要工作台沿确定的路径而离开电脑处理器的时间做其他工作的过程。该软件是由松下来研究发展的，以便于在线监测伺服电机。该元素的伺服系统包括电机、驱动器、编码器和控制器等，并在图3显示出来了，而完整的模型在图4显示，充分顾及到机械成分、切削力和刚度。5 结果在仿真的基础上进行模拟输出如图4所示，在进行的试验中，立铣刀应符合以下规格：高速钢刀具的直径为12毫米，螺旋角刀具直径为30，耙角工具直径为11，工件材料则包括铝和有机玻璃。在实验中，参数的不同则视进给和切削深度而定。以每分钟300毫米的进给速度和2毫米的切削深度切割圆形槽样的有机玻璃块时，得出的加工路线如图5所示。当切削直槽时。错误也需要衡量，也可能观察不到太大的变化。所以这种类型对定位精度和进给率可能没有太大的影响。在切削直槽或圆槽时。降低进给速度来减少误差。另一方面，错误也出自如图6所示的脉冲模型上，如果切削条件仍然与图5那样，则误差范围有所变化，他们是相似的。因此，数学模型代表着一个现实模型应用于端铣操作的铣床上。6 结论在本文提出了数学模型为端铣操作，这是结合仿真模型的伺服装置来控制XY工作台的。这是在实验初建成的，在真正的端铣切削加工中，它们都附着在现有的XY工作台上。在编程和完成定位时，定位误差是不同的。无论是从仿真模拟还是实验设定，都是为了获得表。结果配合密切，正如在图5与图6所显示的那样。因此，在没有做出真正的原型时，这样的一个数学模型是有用的业绩考核的一种新的设计，不过这样即费时且费用昂贵。因此，无论是时间还是投资上，把一个新产品投入市场将引起激烈的竞争。因此，在设计者中机电一体化的设计研究已经被越来越多的人所接受。7 一种新的制造技术-采用高速铣削与一些好处的超高速铣削的方法相比，传统的铣可列为如下：增加切割速度，切割动力和芯片体积，改善表面质量。由于较低水平负载的工具和机床工具的热量从切削区传递给晶片，是为了减少切削力而确保更好的精度，使工件温度相对较低，从而减少了加工时间和加工费用。很多时候，与传统方法相比高速加工被认为是一种由于高的切割速度而提高了生产率。它很少强调提高精度和更好的表面光洁度能提高产品质量。这项研究主要是由赫尔辛基科技大学和芬兰的VTT技术研究中心来证明的，他们为不同类型的材料和产品测试是否适合高速切削。结果由HUT和VTT密切合作共同研究工业状况来证实的。这项测试是对7200个垂直型加工中心海事处进行研究证实的。其主轴是装有深沟球轴承，并能达到最高时速每分钟4500转，功率为5千瓦，X轴和Y轴最大进给速度为每分钟24米，Z轴最大进给速度为每分钟20米，数值控制选择的是海德汉跨国公司的415.耐磨性的刀具材料已被视为是限制切削速度的最重要的因素，高速钢和涂层由于他们低的耐磨性已经证实了我们的研究测试。高切削速度的硬质合金的刀具寿命众所周知是短的。不过，它们可用于加工软材料，金属陶瓷是被提供的整理的钢。像立方氮化硼和聚晶金刚石这种超硬刀具材料，自然是被视为属于改集团的高速加工刀具材料。该刀具适用于高速铣削，并可分为单铣和多铣。在我们这个领域的活动中，我们的实验室还包括了制造业的复杂工件，如制造模具等。在那个领域，主要应用于固体铣刀。根据我们的经验，高速加工的刀具都具有标准的几何形状。应用最广的高速铣削加工是加工钢材，因为他们是在工程中应用最广泛的材料。无论是工件中冷点、热点和塑料模具钢，它们在完成硬化状态后会得到许多钢材。采用高速铣削也可用于加工淬硬钢。它通常用于在整理模具溶洞中作代替放电操作。立方氮化硼工具也通常被使用，主要是因为它们有很多优点，例如它给出了一个替代碳化物。这个问题涉及到由于缺乏有关切削参数为硬质材料的参数方面的知识，使得超高速铣削钢已不能胜任工具的耐磨性。刀具材料和刀具几何形状的发展将使之采用高速铣削不同的钢材的调查可能履行。甚至在一定的锻炼条件下使用高合金工具钢。Mechatronics approach1 CNC machine tools popular science knowledgeDigital control machine tools is the digital information in the form of code (programming instructions), the control tool given by the working procedures, velocity and trajectory of the automatic processing machine, or CNC machine tools. NC machine tool with a wide range of adaptability, processing only when the object changes need to change the procedures for the importation of instruction; processing performance than the general automatic machine tools, precision machining can be complicated surface, thus suitable for processing small quantities, modified frequent, high-precision , The shape and the more complicated parts, and access to good economic results.With the development of numerical control technology, the use of CNC machine tools increasing varieties, lathes, milling machines, boring machine, drilling, grinding machines, machine tools and processing gear EDM machine, and so on. There is also the tool change automatically, with a multi-card processing operations of the processing centres, turning centres and so on.1948, the United States to accept the U.S. Air Force commissioned by the Parsons Corporation, the outline of the development model of aircraft propeller blades of the processing equipment. As example of complex and varied forms, high-precision, difficult to adapt to ordinary processing equipment, therefore proposed the idea of computer-controlled machine tools. 1949, the company in the U.S. Massachusetts Institute of Technology Research servo institutions, with the assistance of CNC machine tools began research and trial production in 1952 by the first successful large-scale copying of vertical milling machine converted the 3-D CNC milling machine, Soon start production.At that time, the NC devices using tube components, size, is expensive, only a few in the aviation industry and other sectors with special needs for processing of complex components; 1959, made a transistor components and printed circuit boards, NC Entered a second-generation devices, reducing size, cost has decreased in 1960 after a relatively simple and economic point of control NC drilling machine, CNC milling machine and line control by rapid development so that the NC machine tools in the machine manufacturing industry Gradually promote the various departments.In order to ensure a great machine to process performance and ability to work for stability, structural design of CNC machine tools are characterized by sufficient rigidity, accuracy, anti-vibration, heat and maintain the stability and accuracy. Feed the mechanical transmission systems linked by ball screw, screw and non-static space gear, so as to minimize reverse gap. Machine tools used by motorized plastic rails, rolling or static guide rails to enhance the smooth movement of low-speed and movement when there is no creeping phenomenon.As a result of a wide speed range of feed-speed servo motor and the main motor, you can not drive or less used and Gear Shift, which simplifies the machines drive mechanism. Paixie facilitate the distribution of machine tools and parts handling, with automatic part of NC machine tools and auto parts Paixie exchange device. Most of CNC machine tools used with the microprocessor PLC, strong, to replace the large number of counters in the relay, raising the machine-control, reliability and flexibility.With micro-electronics technology, computer technology and software technology is developing rapidly, the NC machine tool control system at the growing tendency of small-scale and multi-functional, have improved self-diagnostic features, reliability and greatly improve the system itself will generally NC Automatic programming. The type of CNC machine tools the future will be more diversified, multi-processing operations on the more and more varieties of NC machine tools, laser processing technology will be implemented in cutting machine tools, thereby increasing the number of processes on the scope of the NC machine tool automation Further improve the level and a variety of monitoring, thus forming a flexible manufacturing unit, makes it easy to incorporate highly automated flexible manufacturing systems.It is well known, a machine basic constitution including machine, transmission part, and execution part and control section. Transmission part is the overwhelming majority machine essential important constituent. From machine to working machine partial speed changes, change heading, change mode of motion, power and movement transmission assignment and so on function. All is completes by the transmission device. In some machines (for example machine, automobile) center the transmission device occupies the entire machine majority, therefore the machine operating performance and the operation cost are decided are partial (transmission device) to the transmission the fit and unfit quality in the very great degree. Therefore, in order to adapt the market to the mechanical product request enhances the transmission device the design level to have the vital significance. Since long ago, our country when design mechanical product, generally continues to use traditional the design method, the mechanical product design is the complex process which a morbid state structure, repeatedly iterates, costs the designer massive time and the energy, therefore, regardless of by far could not satisfy users request from the design performance and the design speed, has formed the advanced product request and in backwardness design method contradiction. At the same time, market competition intensifying, also requests the product to face, the low cost, and the short cyclical direction high grade is developing RI. At present, in machinery commonly used transmission design method commonly used theoretical design law. It is the design which carries on according to the existing science and technology theory and the practice knowledge, therefore, the commonly used design calculation formula are many is carries on the theory inferential reasoning in under certain suppositions conditions, again introduces aeries of correction coefficient, but obtains half theory semi-rational formula. Calculates using these formulas time, needs to look up a series of related forms or the graph determined the correction coefficient and certain parameters, the process is troublesome time-consuming: The machine designing is a process in particular which unceasingly revises, unceasingly consummates. The innumerable facts proved that, the experienced outstanding designer often could compared to just leave the school gate, the similarly rich talent designer to design a better product by a quicker speed to come. The expert system technology can help us to realize the expert to design the experience the induction and the use, causes the experience the continuation and development had greatly surmounted” between the priests and disciples space and time limit, thus greatly advanced the design quality and the efficiency enhancement, thus for causes the transmission the design to adapt in the product market demand, develops the mechanical drive to design the expert system, quickly causes the transmission design speed, the computation to be accurate, the plan optimizes into the inevitable tendency. 2 INTRODCUTION A mechatronics approach is developing a mathematical model for the end milling operations on a CNC milling machine to simulate its behavior, is taken up in this paper. The mathematical model of the servomotor controlled XY table, developed elsewhere, is integrated with the proposed model for the end milling operations. Simulations are performed using SIMULINK of MATLAB. An experimental set-up was built to perform end milling operation on an existing XY table. SIMULINK results are validated with the experimental results. Such mathematical models are useful for evaluation of a new design. Hence, the lead time and cost to bring a new design in the market will be drastically reduced.Mechatronics is a concept introduced in Japan in 1980s. Even though people refer to any system having mechanical, electrical, electronics components, for example, washing machine,photocopiers, CNC machines, etc., as mechatronics systems, truly mechatronics! is a design philosophy. In conventional design approach, components of a system are designed by respective experts. For example, a mechanical engineer designs the mechanical components, whereas the electrical engineer designs the electrical components, and so on. Since every designer leaves certain factor of safety (FOS) due to the ignorance of the other fields, the overall FOS is large and the system becomes bulky and expensive. In mechatronics design approach, the whole system is treated as one by taking care of all the components, be it a mechanical, electrical or electronics. As a result overall factor of safety is small and, hence, the systems size and cost are reduced. In this paper, the mechatronics approach to the study of end milling in a CNC machine is taken up to aid the process of new design of a CNC machine table. The study requires the model of the machining process. The characteristics of end milling lies in the regular sequence of individual cuts, corresponding to each successive tooth engagements. These cuts many times are strongly overlapped. To predict the instantaneous cutting forces, mechanistic theory (Fuh and Hwang, 1997) is used. The force model developed here takes the feed of table and rpm of cutter as input parameters and gives the instantaneous force as output at different cutter flutes locations. Mechanical transmission elements of the XY table comprising of motor axes and ball screws are also considered. Since stiffness of the mechanical elements plays an important role in accuracy of machined parts they are also taken into account in the mathematical model, whereas the models of the PMBLDC servo motors of the XY table are taken from Kataria and Mehta (2001). Based on these models, simulations are performed using SIMULINK of MATLAB. An attachment for the end milling operation is also designed and fabricated, which is attached to the already available XY table for experimental verifications of some of the simulation results.3 EXPERIMENTAL SET-UPThe study of proposed end milling operation is assumed to be done in a CNC milling machine. In our study, end milling was carried out on an available XY table. So a frame was designed and fabricated which supports motor and locates the spindle. Figure 1 shows the frame designed and fabricated to carryout the experiments, whereas Fig. 2 shows the photograph of the complete set-up. The spindle of the attachment is designed in such a way that its one end is connected with the AC induction motor shaft providing rotation, whereas the other end is connected to a drilling chuck which is modified to hold the end mill cutter . Fig. 1 End milling attachment2.0 Spindle motor .Power requirements for end milling are done as per the production technology handbook . Based on the power to cut Aluminum by an HSS tool, spindle motor is selected as: 220V, 1440RPM, 250W, single-phase AC induction motor.2.1 FrameThe horizontal link of the frame in the end mill attachment, as shown in Fig. 1, is the critical one as it supports the motor and the spindle against bending forces induced during cutting. This link is designed as simple supported beam. Link cross-section is chosen as: 35mm x 35mm, 3mm thickness, hollow. 2.2 Tool holding deviceIn actual CNC milling machines, draw bar mechanism is used to secure the cutting tool. However, to keep the system simple, here a drilling chuck was modified to serve the purpose of holding the end mill cutter. 2.3 BearingBearing is fixed on the frame which houses the spindle. The forces coming on the spindle are predominantly of bending. So, bearings have to withstand radial forces. Hence, the SKF deep groove ball bearings 6004 are selected. 2.4 PanatermThe system response was observed by using the software package PANATERM , whereas DMCterm is another software was used to communicate with the Galil DMC1822 controller card (Galil, 2000). DMC1822 is a two-axis controller which controls the PMBLDC motors along X and Y axes. Both the software allow online monitoring of the driver, which show errors in terms of the number of pulses, motor RPM, and torque percentage supplied by the motors at any time instant. The positional errors are defined here as the difference between the programmed and achieved positions. 3 SYSTEM MODELLINGThe mathematical model of the complete set-up, comprising of the servo controlled XY table, cutting conditions, etc., is presented in this section. The controller of the XY table is mounted on the PCI slot of the PC, which does all the calculations necessary to move the table along a pre-determined path leaving computer processor time free to do other jobs. The software package PANATERM developed by Panasonic facilitates the online monitoring of the servomotors. The elements of servo system including motor, driver, encoder and the controller are modelled and shown in Fig. 3, whereas the complete model is shown in Fig. 4 that takes care of the mechanical elements, cutting forces and stiffness .Fig. 3 Functional elements of the controller.Fig. 4 Complete SIMULINK (in MATLAB) model.4 RESULTSSimulations are performed in SIMULINK based on the model shown in Fig. 4 and experiments were conducted using an end milling cutter with the following specifications: HSS tool with straight shank of diameter 12mm; Helix angle of tool 30 ; Rake angle of the tool 11 . Work materials are considered as Aluminum and Perspex (polymethyl methalcralyte). For experiments, the parameters varied are feed and depth of cut. For the cutting of a circular slot on Perspex block at 300mm/min feed rate with 2mm depth of cut, errors obtained from PANATERM are shown in Fig. 5. Errors were also measured while cutting straight slot but not much variations were observed. So the type of paths may not have much influence on the positional accuracy, whereas the feed rate has. Lowering the feed rate has reduced the variation of errors during straight or circular slots.On the hand, errors from the SIMULINK model is shown in Fig. 6, where the cutting conditions remained same as in Fig. 5. Note the range of error variations, which is similar, i.e., +/- .075mm. Hence, the mathematical model represents the a realistic model for the end milling operation on a milling machine. 5 CONCLUSIONSMathematical model for the end milling operation is proposed in this paper, which is integrated w