数字控制外文文献翻译、中英文翻译
机械毕业设计英文外文翻译460数字控制 (2)
附录科技译文：Numerical ControlNumerical Control(NC) is a method of controlling the movements of machineComponents by directly inserting coded instructions in the form of numerical data(numbers and data ) into the system.The system automatically interprets these data and converts to output signals. These signals ,in turn control various machine components ,such as turning spindles on and off ,changing tools,moving the work piece or the tools along specific paths,and turning cutting fluits on and off.In order to appreciate the importer of numerical control of machines ,let’s briefly review how a process such as machining has been carried out traditionally .After studying the working drawing of a part, the operator sets up the appropriate process parameters(such as cutting speed ,feed,depth of cut,cutting fluid ,and so on),determines the sequence of operations to be performed,clamps the work piece in a workholding device such as chuck or collet ,and proceeds to make the part .Depending on part shape and the dimensional accuracy specified ,this approach usually requires skilledoperators.Furthermore,the machining procedure followed may depend on the particular operators,and because of the possibilities of human error, the parts produced by the same operator may not all be identical .Part quality may thus depend on the particular operator or even the same operator on different days or different hours of the day. Because of our increased concern with product quality and reducing manufacturing costs,such variability and its effects on product quality are no longer acceptable this situation can be dliminated by numerical control of the mathining operation.We can illustrate the importance of numerical concrol by the following example. Asume that holes have to be drilled on a part in the positions shown in the picture.In the traditional manual method of machining thid part, the operator positions the drill with respect to the workpiece, using as erfererence points any of the three of the method shown. The operator then proceeds to drill these holes. Let,s assume that 100 parts, having exactly the same shape and dimensional accuracy, have to be dielled. Obviously, this operation is going to be tediious because the operator has to go throuth the same motions again and again. Moreover, the probabiluty is high that, faor warious reasons, some of the paths machined will be different fromorthers. Let`s further assume that during this production run, the order for these paths is changed, so that 10 of the paths now require holes in difficult positions. The machinisst now has to reset the mathine , wehich will be time consuming and subject to error. Such operations can be perfomedeasily by numerical conctrol machines that are capable of producing parts reeatedly and accurately and of handling differeent parts by simply londing differeent part programs.In numerical control ,data concerning all aspects of the machining operation,such as locations ,speeds,and cutting fluid,are stored on magnetic tape.,cassettes ,floppy or hard disks,or paper or plastic(Mylar,which is a thermoplastic polyester)tape,.Date are stored on punched 25 mm wide paper or plastic tape ,as originally developed and still used .The concept of NC control is that holes in the tape represent specific information in the form of alphanumeric codes ,The presence (on)or absence (off),of these holes is read by sensing devices in the contuol panel ,which then actuate relays and other devices (called hard-wired contuols),These devices control various mechanical and electrical system in the machine .This method eliminnated manual setting of machine positions and tool paths or the use of templates and othermechanical guides and devices. Conplex operations,such as turning a part having various contours and die sinking in milling machine ,can be carried out.Numerical control has had a major impact on all aspects of manufacturing operations.It is a widely applied technology ,particularly in the following areas:a)Machining centersb)Milling,turning,boring,drilling,and gringingc)Electrical-discharge,laser-beam,and electron-beam machiningd) Water-jet cuttinge) Punching and nibbling .f) Pipe bending and metal spinning.g) Sopt welding and metal spinning.h) Assembly operations.Numerical control machines are now used extensively in small-and-medium-quantity(typically 500 parts or less)of a wide variety of parts in small shops and large manufacture facilities. Older machines can be retrofitted with numerical control.Advantages and Limitations Numerical control has following advantages over conventional method of machine control:1.Flexibility of operation and ability to produce complex shape with good dimensional accuracy,repeatability,reduced scrap loss,and high production rates ,productivity,and product quality.2.Tooling costs are reduced,since templates and other fixtures are not required.3.Machine adjustments are easy to make with minicomputer and digital readout.4.More operations can be performed with each setup,and less lead time for setup and machining is required compared to conventional methods.Design changes are facilitated,and inventory is reduced.5.Programs can prepared rapidly and can be recalled at any time utilizing microprocessors,Less paperwork is involved.6.Faster prototype productiong is possible.7.Required operator skill is less,and the operator has more time to attend to other tasks in the work area.The major limitations of NC are the relatively high cost of the equipment and the need for programming and specialmaintenance,requiring trained personal.Because NC machines are complex systems,breakdowns can be very costly,so preventive maintenance is essential.However,these limitations are often easily outweighed by the overall economic advantages of NC.One of the most fundamental concepts in the area of advanced manufacturing technologies is numerical control(NC) Controlling a machine tool using a punched tape or stored program is known as numerical control (NC).NC has been defined by the ElectronicIndustries.Association(EIA)as "a system in which actions are controlled by the direct insertion of numerical data at some point.The numerical data at some point.The numerical data required to produce a part is known as a part program.A numerical control machine toll system contains a machine control unit(MCU) and the machine tool itself(Fig2.16)The MCU is further divided into two elements:The data processing unit(DPU)and the control loops unit (CLU). The DPU processes the code data from the tape or other media and passes information on the position of each axis,required direction of motion,feed rate, and auxiliary function control signals to the CLU. The CLU operates the drive mechanisms ofeach of the axes and signals the completion of operation.The DPU sequentially reads the data.When each line has completed execution of operation.The DPU sequentially read thedata.When each line has completed execution as noted by the CLU,another line of data is read.A data processing unit consists of some or all of the following parts:1)Data input device such as a paper tapereader,RS232-C port,etc2)Data-reading circuits and parity-checking logic3)Decoding circuits for distributing data among the controlled axes4)An interpolator,which supplies machine-motion commands between data points for tool motionA control loops unit,on the other hand consists of the following:1)Position control loops for all the axes ofmotion,where ach axis has a separate control loop2)Velocity control loops,where feed control is required3)Deceleration and backlash take up circuits4)Auxiliary functions control,such as coolanton/off,gear changes,spindle on/off controlGeometric and kinematics data are typically fed from the DPU to the CLU.The CLU then governs the physical system based on the data form the DPU.Numerical control was developed to overcome the limitation of human operators,and it has done so.Numerical control machines are more accurate than manually operated machines,they can produce parts more uniformly,they are faster,and the long-run tooling costs are lower.The development of NC led to the development of several Other innovations in manufacturing technology ;Electic discharge machiningLaser—cutingElectron beam weldingNumerical control has also made maching tools more versatile their manually operated predecessors . An NC machine tool can automatically produce a wide variety of parts ,each involving an assortment of widely varied and complex machining processes . Numerical control has allowed manufacturers to undertaken the production of part ,each involving an assortment of widely varied and complex machining processes .Numerical control has allowed manufactures to undertaken the production of products thatwould not have been feasible from an economic perspective using manually controlled machine tools and processes.翻译：数字控制数控是一种用数字控制机床各部件运动的方法，通过直接向系统输入指令代码（数字和字母)完成的。
外文文献翻译译稿和原文
外文文献翻译译稿1卡尔曼滤波的一个典型实例是从一组有限的，包含噪声的，通过对物体位置的观察序列（可能有偏差）预测出物体的位置的坐标及速度。
在很多工程应用（如雷达、计算机视觉）中都可以找到它的身影。
同时，卡尔曼滤波也是控制理论以及控制系统工程中的一个重要课题。
例如，对于雷达来说，人们感兴趣的是其能够跟踪目标。
但目标的位置、速度、加速度的测量值往往在任何时候都有噪声。
卡尔曼滤波利用目标的动态信息，设法去掉噪声的影响，得到一个关于目标位置的好的估计。
这个估计可以是对当前目标位置的估计（滤波），也可以是对于将来位置的估计（预测），也可以是对过去位置的估计（插值或平滑）。
命名[编辑]这种滤波方法以它的发明者鲁道夫.E.卡尔曼（Rudolph E. Kalman）命名，但是根据文献可知实际上Peter Swerling在更早之前就提出了一种类似的算法。
斯坦利。
施密特（Stanley Schmidt）首次实现了卡尔曼滤波器。
卡尔曼在NASA埃姆斯研究中心访问时，发现他的方法对于解决阿波罗计划的轨道预测很有用，后来阿波罗飞船的导航电脑便使用了这种滤波器。
关于这种滤波器的论文由Swerling（1958）、Kalman (1960)与Kalman and Bucy（1961）发表。
目前，卡尔曼滤波已经有很多不同的实现。
卡尔曼最初提出的形式现在一般称为简单卡尔曼滤波器。
除此以外，还有施密特扩展滤波器、信息滤波器以及很多Bierman, Thornton开发的平方根滤波器的变种。
也许最常见的卡尔曼滤波器是锁相环，它在收音机、计算机和几乎任何视频或通讯设备中广泛存在。
以下的讨论需要线性代数以及概率论的一般知识。
卡尔曼滤波建立在线性代数和隐马尔可夫模型（hidden Markov model）上。
其基本动态系统可以用一个马尔可夫链表示，该马尔可夫链建立在一个被高斯噪声（即正态分布的噪声）干扰的线性算子上的。
系统的状态可以用一个元素为实数的向量表示。
文献综述及外文文献翻译
⽂献综述及外⽂⽂献翻译华中科技⼤学⽂华学院毕业设计（论⽂）外⽂⽂献翻译（本科学⽣⽤）题⽬：Plc based control system for the music fountain 学⽣姓名：_周训⽅___学号：060108011117 学部（系）: 信息学部专业年级: _06⾃动化（1）班_指导教师：张晓丹___职称或学位：助教__20 年⽉⽇外⽂⽂献翻译（译成中⽂1000字左右）：【主要阅读⽂献不少于5篇，译⽂后附注⽂献信息，包括：作者、书名（或论⽂题⽬）、出版社（或刊物名称）、出版时间（或刊号）、页码。
提供所译外⽂资料附件（印刷类含封⾯、封底、⽬录、翻译部分的复印件等，⽹站类的请附⽹址及原⽂】英⽂节选原⽂：Central Processing Unit (CPU) is the brain of a PLC controller. CPU itself is usually one of the microcontrollers. Aforetime these were 8-bit microcontrollers such as 8051, and now these are 16-and 32-bit microcontrollers. Unspoken rule is that you’ll find mostly Hitachi and Fujicu microcontrollers in PLC controllers by Japanese makers, Siemens in European controllers, and Motorola microcontrollers in American ones. CPU also takes care of communication, interconnectedness among other parts of PLC controllers, program execution, memory operation, overseeing input and setting up of an output. PLC controllers have complex routines for memory checkup in order to ensure that PLC memory was not damaged (memory checkup is done for safety reasons).Generally speaking, CPU unit makes a great number of check-ups of the PLC controller itself so eventual errors would be discovered early. You can simply look at any PLC controller and see that there are several indicators in the form. of light diodes for error signalization.System memory (today mostly implemented in FLASH technology) is used by a PLC for a process control system. Aside form. this operating system it also contains a user program translated forma ladder diagram to a binary form. FLASH memory contents can be changed only in case where user program is being changed. PLC controllers were used earlier instead of PLASH memory and have had EPROM memory instead of FLASH memory which had to be erased with UV lamp and programmed on programmers. With the use of FLASH technology this process was greatly shortened. Reprogramming a program memory is done through a serial cable in a program for application development.User memory is divided into blocks having special functions. Some parts of a memory are used for storing input and output status. The real status of an input is stored either as “1”or as “0”in a specific memory bit/ each input or output has one corresponding b it in memory. Other parts of memory are used to store variable contents for variables used in used program. For example, time value, or counter value would be stored in this part of the memory.PLC controller can be reprogrammed through a computer (usual way), but also through manual programmers (consoles). This practically means that each PLC controller can programmed through a computer if you have the software needed for programming. Today’s transmission computers are ideal for reprogramming a PLC cont roller in factory itself. This is of great importance to industry. Once the system is corrected, it is also important to read the right program into a PLC again. It is also good to check from time to time whether program in a PLC has not changed. This helps to avoid hazardous situations in factory rooms (some automakers have established communication networks which regularly check programs in PLC controllers to ensure execution only of good programs). Almost every program for programming a PLC controller possesses various useful options such as: forced switching on and off of the system input/outputs (I/O lines),program follow up in real time as well as documenting a diagram. This documenting is necessary to understand and define failures and malfunctions. Programmer can add remarks, names of input or output devices, and comments that can be useful when finding errors, or with system maintenance. Adding comments and remarks enables any technician (and not just a person who developed the system) to understand a ladder diagram right away. Comments and remarks can even quote precisely part numbers if replacements would be needed. This would speed up a repair of any problems that come up due to bad parts. The old way was such that a person who developed a system had protection on the program, so nobody aside from this person could understand how it was done. Correctly documented ladder diagram allows any technician to understand thoroughly how system functions.Electrical supply is used in bringing electrical energy to central processing unit. Most PLC controllers work either at 24 VDC or 220 VAC. On some PLC controllers you’ll find electrical supply as a separate module. Those are usually bigger PLC controllers, while small and medium series already contain the supply module. User has to determine how much current to take from I/O module to ensure that electrical supply provides appropriate amount of current. Different types of modules use different amounts of electrical current. This electrical supply is usually not used to start external input or output. User has to provide separate supplies in starting PLC controller inputs because then you can ensure so called “pure” supply for the PLC controller. With pure supply we mean supply where industrial environment can not affect it damagingly. Some of the smaller PLC controllers supply their inputs with voltage from a small supply source already incorporated into a PLC.中⽂翻译：从结构上分，PLC分为固定式和组合式（模块式）两种。
计算机专业英语的课文与翻译
Unit 8 Computer NetworkingText 1 Data CommunicationsThe end equipment can be computers, printers, keyboards, CRTs, and so on.They are either generates the digital information for transmission or uses the received digital data. This equipment generally operates digital information internally in word units.DTE is data terminal equipment. A station controller STACO is the corresponding unit at the secondaries. At one time, the DTE was the last piece of equipment that belonged to the subscriber in a data link system. Between the DTEs, first is the modem, and then is the communications equipment. The communication equipment is owned and maintained by Telco. Data communications equipment DCE accepts the serial data stream from the DTE. And DCE converts it to some form of analog signal suitable for transmission on voice-grade lines. At the receive end, the DCE performs the reverse function. It converts the received analog signal to a serial digital data stream. The simplest form of DCE is a modem modulator/demodulator or data set. At the transmit end, the modem can be considered a form of digital-to-analog converter.While at the receive end, it can be considered a form of analog-to-digital converter.参考译文数据通信终端设备可以是计算机、打印机、键盘、CRT等;它们可以生成要发送的数字信息,也可以使用所接收的数字数据;这种设备通常在内部以字为单位处理数字信息;DTE一般称为数据终端设备;辅助设备一方的相应设备是工作站控制器STACO;同时,DTE也是数据链路系统中属于用户端的最后一个设备;在两个DTE之间,先是调制解调器,接着是属于Telco电话公司维护的通信设备;数据通信设备DCE从DTE接收串行数据流,并将其转换成适合于在语音线路上发送的某种模拟信号形式;在接收端,DCE完成相反的功能,把接收到的模拟信号转换成串行数字数据流;最简单的DCE是调制解调器或数据传送机;在发送端,调制解调器可以视为一种数/模转换器,而在接收端则可视为一种模／数转换器;Text 2 Architecture of Computer NetworksComputer network is a complex unit, it consists of two or more connected computing units. It is used for the purpose of data communication and resource sharing. Design of a network and its logical structure should comply with a set of design principles. They include: the organization of functions, the description of data formats and procedure.In the following two sections we will discuss two important network architectures, the OSI reference model and the TCP/IP reference model.(1)the OSI reference modelThe OSI open systems interconnection model was created by the ISO. This model is a foundation for comparing protocols; However, more protocols deviate from the rules set up by the OSI model.The OSI model has seven layers. Note that the OSI model itself is not a network architecture.It just tells what each layer should do. However, ISO has also produced standards for all the layers. Each one has been published as a separate international standard.(2)the TCP/IP reference modelTCP/IP is a communication protocol; it provides many different networking services.The TCP/IP Internet protocol suite is formed from two standards: the TCP Transmission Control Protocol and the IP Internet Protocol. TCP means it is on the transport layer. IP means it is on the network layer. On top of the transport layer is the application layer. It contains all the higher-level protocols. The early ones included virtual terminal TELNET, file transfer FTP, electronic mail SMTP and domain name service DNS.As we know, TCP/IP is the foundation of the Internet.These protocols are continually changing and evolving to support the needs of the user community.参考译文计算机网络结构计算机网络是由两个或多个计算机设备互连而成的一种复合系统,它用于数据通信和资源共享;网络设计及其逻辑结构应该遵循一套设计原则,其中包括：功能的组织以及数据格式和过程的说明;在下面的两小节里,我们将讨论两个重要的网络体系结构,即OSI参考模型和TCP/IP参考模型;(1)OSI参考模型OSI模型开放系统互联参考模型是由国际标准化组织ISO开发的一个建议;相对于其他协议来说,此种模式为基础模式;然而,更多的协议是背离OSI模型的;OSI模型有7层;应该注意的是,OSI模型本身并不是一种网络体系结构,它只是说明每一层应该做什么;然而,ISO还是对各层制定了标准,每一层都是作为一个单独的国际标准来颁布的;(2)TCP/IP参考模型TCP/IP参考模型是一种传输协议,提供了许多不同的网络服务;TCP/IP协议组由TCP传输控制协议和IP网际协议两部分组成;TCP表明是处于传输层,IP意为是在网络层;在传输层上面是应用层;应用层包括所有高层协议;早期的协议包括虚拟终端TELNET、文件传送协议FTP、电子邮件SMTP和域名服务DNS;现在我们知道,TCP/IP协议是因特网的基础;这些协议在用户们的支持下不断地改变和进化着;Text 3 Local Area NetworkA LAN Local area data network is a group of computers. The work devices connected together usually within the same building. By definition, the connections must be high-speed and relatively inexpensive . token ring or Ethernet. For example, a LAN may be used to interconnect workstations distributed around offices within a single building or a group of buildings such as a university campus.LANs consist of carefully selected groups of components hardware and software. They are configured for the specific requirements of the organization. A LAN is generally limited to the size of a department or an organization. And a LAN often consists of 2 to 100 devices. LANs usually contain resources such as servers, printers, and connections to other networks through internetworking devices. The internetworking devices include switches and routers.In the next section we will discuss the structure of the different types of LAN.(1)TopologyMost wide area networks, such as the PSTN, use a mesh sometimes referred to as a network topology. With LANs, however, the limited physical separation of the subscriber DTEs allows simpler topologies to be used. The four topologies in common use are star, bus, ring and hub.The most widespread topology for LANs designed to function as data communication subnetworks for the interconnection of local computer-based equipment is the hub topology. It is a variation of the bus andring.(2)Transmission mediaTwisted pair, coaxial cable and optical fibre are the three main types of transmission medium used for LANs.(3)Medium access control methodsTwo techniques have been adopted for use of the medium access control in the LANs. One is carrier-sense-multiple-access with collision detection, and the other is control token.参考译文局域网局域数据网局域网由若干计算机组成;通常是一幢楼内的工作设备被连接在一起;通过定义可知,这种连接一定是高速并且相对廉价的如：令牌网和以太网;例如,一个局域网可以把一幢楼里或像大学校园内楼群里的各个办公室的工作站连在一起;局域网是由精心挑选的各组设备硬件和软件构成的;它们根据组织的各种特殊需要来配置;局域网的大小一般限制在一个部门或者一个组织,由2～100台电脑组成;局域网经常包含一些资源,如一些服务器和打印机,而且可以通过网络设备与其他的网络连接;这些网络设备包括交换机和路由器等;接下来,我们将讨论不同类型局域网的结构;(1)拓扑结构大多数广域网,如公共电话交换网PSTN,使用网状有时称为网络拓扑结构；而局域网由于用户数据终端设备相距很近,可采用简单的拓扑结构;常用的有星形、总线、环形和集线器等4种拓扑结构;应用最广的、用于互连本部门计算机设备以进行数据通信的局域网拓扑结构是集线器拓扑结构;这种拓扑结构是总线和环形拓扑结构的变种;(2)传输媒体双绞线、同轴电缆和光纤是局域网采用的3种主要传输媒体;(3)媒体访问控制方法局域网中采用了两种媒体访问控制技术,一种是载波侦听多路访问／冲突检测技术CSMA/CD,另一种是令牌控制技术;Text 4 InternetThe Internet is used by millions of people across the world to communicate business and personal information. The Internet is huge. Then we will talk about the difference of “an internet”and “ the Internet”.An internet note the lower case "i" is a computer network. It allows computers with distinctive software and hardware to communicate. Many kinds of computers can be connected to an internet. Each computer can serve a specialized role. It offers a wide variety of services to its users.The Internet is specific kind of internet. In The Internet Passport, the Internet will be defined as the network of networks. It follows a set of rules known as the "Internet Protocol IP suite".But what does this mean to you It means that any computer that is connected to the Internet can communicate with any other Internet computer. From the user's perspective, this works much like the telephone system works. You can dial from your phone to any other phone on the system, no matter what kind of telephone you have; you only need to know the phone number of the person you want to reach.With an Internet connection you can get some of the basic services available are:•E-mail. It’s a fast, easy, and inexpensive way to communicate with other Internet users around the world.•Telnet. It allows a user to log into a remote computer as though it were a local system.•FTP. It allows a user to transfer virtually every kind of file that can be stored on a computer from one Internet-connected computer to another.•Usenet news. It’s a distributed bulletin board which offers a combination news and discussion service on thousands of topics.•World Wide Web . It’s a hypertext interface to Internet information resources. Also, through an Internet connection, you can:•access online library catalogs.•copy computer files or software from archives.•access databases for teaching or research.•obtain free electronic books.•use educational and information services.•use directory services to find Internet users.•access supercomputer sites.It was estimated that at this rapid growth everyone in the world would have an e-mail address in the near future.参考译文互联网因特网是世界上很多人用来进行商业贸易和个人信息交流的网络,它非常巨大;接下来,我们将讨论互联网及因特网;互联网internet注意小写字母i是一种计算机网络,该网络上的计算机在通信时可以使用不同的软件和硬件;多种计算机都可以连入互联网,每台计算机都可以有一独特作用;一个互联网可以向它的用户提供各式各样的业务;因特网Internet是一种专用互联网;因特网在它的证书中定义为网络的网络,该网络使用了一组叫做互联网协议IP组的规则;但对你来说,这意味着什么呢这表明连接到因特网上的计算机可以与因特网上任何其他计算机通信;从用户的角度来看,其工作方式很像电话系统的工作方式;在电话系统内,可以从你的电话机拨打任何其他电话,而不管你使用什么样的电话机,你只需知道对方的电话号码即可;你可以通过因特网得到的基本服务如下：•电子邮件;它是与世界范围内的因特网用户进行联系的一种快速、方便、廉价的交流方式;•远程登录;允许用户连接到远程计算机上,就像这台远程计算机是本地机一样;•文件传输协议;该协议可以将存储在计算机上的各种文件,从因特网上的一台计算机传送给另一台计算机;•新闻组网络系统;一种分布式的电子公告牌,它能提供有关上千种话题的新闻和讨论服务;•万维网;一种因特网信息资源的超文本界面;•访问在线图书馆目录;•从计算机档案库存储器中拷贝文件或软件;•访问教学或科研数据库;•获取免费电子图书;•使用教育和信息服务;•使用目录服务以查找因特网用户;•访问超级计算机站点;估计以这样的高速发展,在不久的将来世界上每个人都将拥有至少一个电子邮件地址;Text 5 The World Wide WebThe World Wide Web also known as or Web is one of the fastest-growing Internet software applications. It is an architectural framework. It linked documents spread out over thousands of machines for accessing all over the Internet.The World Wide Web ties the computers together into a vast collection of interactive multimedia resources. The is a way of exchange information between computers on the Internet.The Web is built around hypertext and hypermedia. A hypertext document has certain keywords or phrases linked to other online documents. A person reading a hypertext document about mobile phone, for example, might be able to select the highlighted word “Nokia 3310”, and he call up another document giving more information about that particular type. With documents intertwined by links into a web of information, you can select paths to browse online resources, a process often referred to as surfing.Hypermedia extends the concept of hypertext to other forms of information. They include: images, sounds, and even video clips. If a person read a hypermedia document about mobile phones, then he might select a video show of a phone and hear the ring of it.The World Wide Web also subsumes previous Internet information systems such as Gopher and FTP. These resources can still be accessed through the Web. But the Web offered by these more restricted connection methods. Now the Web provides a wealth of additional capabilities.Thousands of computers around the world are now connected to the Web. They offer a huge variety of information and services to visitors. These online documents are generally referred to as pages. They are composed and supported by various people and organizations. Web pages are available for an amazing variety of tasks ranging from the playful to the serious. You can get many services access Web pages. For example, you can search database of mailing lists, you can see pictures of your favorite band and their concert schedule, or you can take a “tour” through a foreign country. Thousands of links to new services are added to the Web each day, and its growth has been explosive.参考译文万维网万维网又称或Web是因特网上发展最快的应用软件之一;它是一种结构化框架,用于访问遍布在因特网上的成千上万台机器中的链接文档;万维网把这些计算机连接成了一个巨大的交互式多媒体资源库,它是因特网上的计算机之间进行信息交流的一种方式;Web是用超文本和超媒体设计的;超文本文档中的一些关键词或短语被链接到了其他的在线文档中;例如,某人在阅读一篇有关移动电话的超文本文档时,如果他选择高亮显示的词“诺基亚3310”,就能链接到另一篇有关这一类型移动电话的文章,从而可以获取更多的信息;网络文章通过链接形成了一个网络信息资源库,用户可以选择路径来浏览这些在线资源,这种行为通常被称为“网上冲浪”;超媒体将超文本的概念扩展到了其他的信息形式,其中包括图片、声音,甚至是录像剪辑;在超媒体文档中阅读有关移动电话的文章时,读者可以选择关于该电话的视频演示,还能听见铃声;万维网也包括了以前的因特网信息系统,如Gopher 和FTP;这些资源仍然可以通过网络访问,但是以前那些连接方式的局限性很大,现在的网络提供了许多先辈们没能提供的功能;现在世界上成千上万的计算机都连接到了网络上,而且为访问者提供了相当多的信息和服务;这些由不同的人和组织编写和支持的在线文档被称为网页;Web网页可以跨越从诙谐到严肃的各种风格;通过访问网页,用户可以查看邮件数据库,查阅自己喜爱的乐队的图片和他们的演出时间表,或去国外周游一圈;现在每天都会增加上千种新的服务链接,万维网已经飞速发展起来了;。
外文翻译Numerically Controlled (NC) Machines
本科生毕业设计（论文）外文翻译毕业设计（论文）题目：剪叉式物流液压升降台外文题目：Numerically Controlled (NC) Machines译文题目：数控机床学生姓名：张龙专业：机械设计制造及其自动化指导教师姓名：张凯评阅日期：正文内容小四号字，宋体，行距1.5倍行距。
Numerically Controlled (NC) MachinesWith automatics, programming is expensive and can be justified only for long production runs. However, with machines incorporating feedback control, programs can be provided in the form of punched tapes or punched cards, which are relatively inexpensive to produce compared with disc and drum cams. These machines are known as numerically controlled (NC) machines and can be used economically in small-batch production.As the name implies, numerical control involves control on the basis of numerical information that specifies the relative position of the tool and workpiece. From the block diagram for a machine-tool control system in Fig. 12 it can be seen that two essential elements are added to an otherwise standard machine.The first added element is a means of driving the machine table or toolholder by a servomotor, and hence the motion of the tool or workpiece depends on the signal passed to the servomotor. The second added element is a transducer that continuously monitors the position of the tool or workpiece. The signal from the transducer is compared with that obtained from the tape, and any difference (or error) is converted to analog form, amplified, and used to drive the servomotor until the tool or workpiece position agrees with the position specified by the information on the tape.Fig. 12: Feedback loop for one axis of a machine-tool control system There are two basic types of NC systems: the point-to-point, or positioning, system and the continuous-path, or contouring, system. The point-to-point system would be applied, for example, to a vertical-drilling machine. If control of the two horizontal-motion axes of the table supporting the workpiece is arranged, the machine can be programmed to locate and then drill a specified pattern of holes. In the point-to-point system the path of the tool relative to the workpiece between holes is not important, and only the coordinates of the end point of each motion of the table are specified. The continuous-path system would be applied, for example, to a vertical-milling machine that was required to end mill a complicated shape, such as cam or pocket in a workpiece. In the continuous-path system the position of the tool relative to the workpiece must be continuously controlled while workpieces are being machined.With continuous-path, or contouring, systems the position of the tool relative to the workpiece is specified by a series of coordinates, and the control system is designed to follow a path between these points by interpolation. Some machines follow a straight-line path (linear interpolation); others follow a curved path (circular or parabolic interpolation).Numerical control can be applied to motions along or about any axis,·but two or three-axis control systems are the most common. In general, vertical-milling machines and lathes utilize continuous-path, or contouring control. Vertical-drilling machines jig borers, and small milling machines often use positional control.One sophisticated form of NC machine is known as the machining center. This machine is generally a vertical-milling machine with several axes of control and with automatic tool-changing facilities. The tools are usually held in a rotary magazine, and tool changes are commanded by the punched tape. Thus, with a machining center a complicated workpiece can be completely machined on all faces except the base through a combination of milling, drilling, boring, facing, reaming, and tapping operations. This type of system is therefore most suitable for the batch production of main components.A further refinement of numerical control is adaptive control. This type of system can adapt itself to the prevailing circumstances. These circumstances are measured by the system itself and might include the power required for the machining operation, the wear of the cutting tool or grinding wheel, the forces generated, or the onset of chatter or instability. The system ideally would be designed for automatic adjustment of the feed, speed, or tool position to produce components at minimum cost and within the tolerance specified. Such a system would be very expensive and has not yet found wide application.A relatively simple adaptive control system would automatically vary the cutting speed and feed in such a way as to maximize metal-removal rates without exceeding predetermined cutting forces and power consumption. Systems of this type are relatively inexpensive and can machine under near-optimum conditions.数控机床伴随着自动化产生，只有在长期的生产运行中，编程的价格很昂贵，同时又是合理的。
计算机网络中英文互译
计算机网络中英翻译ACK (ACKnowledgement) 确认帧ADSL (Asymmetric Digital Subscriber Line) 非对称数字用户线AN (Access Network ）接入网ANSI (American National Standards Institute) 美国国家标准协会AP (Access Point) 接入点API (Application Programming Interface) 应用编程接口APNIC (Asia Pacific Network Information Center) 亚太网络信息中心ARP （ Address Resolution Protocol ）地址解析协议ARPA (Advanced Research Project Agency)美国国防部远景研究规划局（高级研究计划署）ARQ (Automatic Repeat reQuest) 自动请求重发ATM (Asynchronous Transfer Mode) 异步传递方式ATU (Access Termination Unit) 接入端接单元ATU-C (Access Termination Unit Central Office ）端局接入端接单元ATU-R (Access Termination Unit Remote) 远端接入端接单元AUI (Attachment Unit Interface ）连接接口单元AWT （ Abstract Window Toolkit ）抽象窗口工具箱BECN (Backward Explicit Congestion Notification) 反向显式拥塞通知BER (Basic Encoding Rule) 基本编码规则BGP (Border Gateway Protocol) 边界网关协议BSA (Basic Service Area) 基本服务区BSS (Basic Service Set) 基本服务集BNA 宝来网络体系结构CAC (Connection Admission Control) 连接准许控制CAP (Carrierless Amplitude Phase) 无载波振幅相位调制CATV (Community Antenna TV, CAble TV) 有线电视CBR （ Constant Bit Rate ）恒定比特率CCIR (Consultative Committee，International Radio) 国际无线电咨询委员会CCITT (Consultative Committee, International Telegraph and Telephone)国际电报电话咨询委员会CCP 通信控制处理机CDM (Code Division Multiplexing) 码分复用CDMA (Code Division Multiplex Access) 码分多址CNNIC (Network Information Center of China) 中国互联网络信息中心CRC (Cyclic Redundancy Check) 循环冗余检验CSMA/CD (Carrier Sense Multiple Access ／ Collision Detection)载波监听多点接入/碰撞检测CSU/DSU （ Channel Service Unit/Data Service Unit) 信道服务单元／数据服务单元CTD (Cell Transfer Delay) 信元传送时延DACS (Digital Access and Cross-connect System) 数字交接系统DCA 数据通信体系结构DCE (Data Circuit-terminating Equipment) 数据电路端接设备DE (Discard Eligibility) 丢弃指示DES (Data Encryption Standard) 数据加密标准DHCP (Dynamic Host Configuration Protocol) 动态主机配置协议DLCI (Data Link Connection Identifier) 数据链路连接标识符DMT (Discrete Multi-Tone) 离散多音（调制）DNS (Domain Name System) 域名系统DNA 数据网络系统结构DSL (Digital Subscriber Line) 数字用户线DSLAM (DSL Access Multiplexer) 数字用户线接入复用器DSSS (Direct Sequence Spread Spectrum) 直接序列扩频DTE (Data Terminal Equipment) 数据终端设备DVMRP (Distance Vector Multicast Routing Protocol) 距离向量多播路由选择协议DWDM (Dense WDM) 密集波分复用EGP (External Gateway Protocol) 外部网关协议EIA (Electronic Industries Association ）美国电子工业协会ESP (Encapsulating Security Payload) 封装安全有效载荷ESS 伍 xtended Service Set) 扩展的服务集FCS (Frame Check Sequence) 帧检验序列FDDI (Fiber Distributed Data Interface ）光纤分布式数据接口FDM (Frequency Division Multiplexing) 频分复用FEC (Forwarding Equivalence Class) 转发等价类FEC (Forward Error Correction) 前向纠错FHSS (Frequency Hopping Spread Spectrum) 跳频扩频FIFO （ First In First Out) 先进先出FQ (Fair Queuing) 公平排队FR (Frame Relay) 帧中继FSK (Frequency Shift Keying) 移频键控FTP (File Transfer Protocol ）文件传送协议FTTB (Fiber To The Building) 光纤到大楼FTTC (Fiber To The Curb ）光纤到路边FTTH (Fiber To The Home) 光纤到家FTTD (Fiber To The Desk) 光纤到桌面FTTZ(Fiber To The Zone ）光纤到小区FTTO (Fiber To The Office) 光纤到办公室FTTF (Fiber To The Floor) 光纤到楼层GIF (Graphics Interchange Format) 图形交换格式GII (Global Information Infrastructure) 全球信息基础结构，全球信息基础设施GFC （ Generic Flow Control) 通用流量控制GSM (Group Special Mobile) 群组专用移动通信体制HDLC (High-level Data Link Control) 面向比特的链路控制规程HDSL (High speed DSL) 高速数字用户线HEC (Header Error Control) 首部差错控制HFC (Hybrid Fiber Coax) 光纤同轴混合（网）HTML (HyperText Markup Language) 超文本置标语言HTTP (HyperText Transfer Protocol) 超文本传送协议IAB (Internet Architecture Board) 因特网体系结构委员会IAC （ Interpret As Command ）作为命令解释IAHC (Internet International Ad Hoc Committee ）因特网国际特别委员会ICMP （ Internet Control Message Protocol ）因特网控制报文协议IDEA (International Data Encryption Algorithm) 国际数据加密算法IEEE电气和电子工程师协会IESG (Internet Engineering Steering Group) 因特网工程指导小组IETF (Internet Engineering Task Force) 因特网工程部IFS (Inter Frame Space) 帧间间隔IGMP (Internet Group Management Protocol) 因特网组管理协议IGP (Interior Gateway Protocol) 内部网关协议IM (Instant Messaging) 即时传信IMAP (Internet Message Access Protocol) 因特网报文存取协议IMP （ Interface Message Processor) 接口报文处理机IP (Internet Protocol ）网际协议IR (InfraRed ）红外技术IRTF （ Internet Research Task Force ）因特网研究部ISDN (Integrated Services Digital Network) 综合业务数字网ISO （ International Organization for Standardization ）国际标准化组织ISOC (Internet Society) 因特网协会ISP （ Internet Service Provider) 因特网服务提供者ITU （ International Telecommunication Union ）国际电信联盟ITU-T （ ITU Telecommunication Standardization Sector) 国际电信联盟电信标准化部门JPEG (Joint Photographic Expert Group) 联合图像专家组标准KDC (Key Distribution Center) 密钥分配中心LAN (Local Area Network ）局域网LANE (LAN Emulation ）局域网仿真LAPB (Link Access Procedure Balanced) 链路接入规程（平衡型）LCP (Link Control Protocol) 链路控制协议LDP (Label Distribution Protocol) 标记分配协议LLC (Logical Link Control) 逻辑链路控制LSP (Label Switched Path) 标记交换路径LSR (Label Switching Router) 标记交换路由器MAC (Medium Access Control) 媒体接入控制MAN (Metropolitan Area Network) 城域网MAU (Medium Attachment Unit) 媒体连接单元MBONE (Multicast Backbone On the InterNEt ）多播主干网MBS (Maximum Burst Size ）最大突发长度MCR (Minimum Cell Rate ）最小信元速率 MCU (Multipoint Control Unit)多点控制单元MD (Message Digest) 报文摘要MDI (Medium Dependent Interface ）媒体相关接口MIB (Management Information Base) 管理信息库MIME (Multipurpose Internet Mail Extensions) 通用因特网邮件扩充modem 调制解调器MOTIF (Message Oriented Text Interchange System) 面向报文的电文交换系统MPEG (Motion Picture Experts Group) 活动图像专家组标准MPOA (MultiProtocol Over ATM) 多协议在 ATM 上运行MPLS (MultiProtocol Label Switching) 多协议标记交换MRU (Maximum Receive Unit) 最大接收单元MSS (Maximum Segment Size) 最长报文段MTU (Maximum Transfer Unit) 最大传送单元NAK (Negative AcKnowlegement) 否认帧NAP （ Network Access Point) 网络接入点N.ISDN (Narrowband-ISDN) 窄带综合业务数字网NAT (Network Address Translation ）网络地址转换NAV (Network Al location Vector) 网络分配向量NCP (Network Control Protocol) 网络控制协议NFS (Network File System) 网络文件系统NGI 下一代因特网计划NIA 网络适配器NIC (Network Interface Card) 网络接口卡、网卡NII (National Information Infrastructure) 国家信息基础结构，国家信息基础设施NLRI (Network Layer Reachability Information) 网络层可达性信息NNI (Network-Node Interface) 网络结点接口NSF (National Science Foundation) （美国）国家科学基金会NVT (Network Virtual Terminal ）网络虚拟终端ODBC （Open Database Connection）开放数据库互连OSF （Open Software Fundation ）开放软件基金会OSI （Open System Interconnection ）开放系统互联PBX （Private Branch eXchange ）用户交换机PCM (Pulse Code Modulation ) 脉冲编码调制PCN (Personal Communications Network ) 个人通信网络PCR （Peak Cell Rate ）峰值信元速率PCS 个人通信服务 Personal Communications ServicePDH 准同步数字系列PDA 个人数字助理 Personal Digital AssistantPDN 公用数据网 Public Data NetworkPDU 协议数据单元 Protocol Data UnitPER 分组差错率 packet error ratePIR 分组插入率 packet insertion ratePLCP 物理层会聚协议 Physical Layer Convergence ProtocolPLR 分组丢失率 packet loss ratePMD 物理媒体相关（子层） Physical Medium DependentPPP 点到点协议 Point to Point ProtocolPPTP 点对点隧道协议PRM 协议参考模型 Protocol Reference ModelPRN 分组无线网 Packet Radio NetworkPSN 分组交换节点 Packet Switch NodePSTN 公用电话交换网 Public Switched Telephone NetworkRARP 逆向地址解析协议 Reverse Address Resolution ProtocolRAS 远程访问服务器RFC 请求评注 Request for CommentsRMON 远程网络管理Router 路由器RPC 远程过程调用 Remote Procedure CallRSVP 资源重复利用协议RTP 接收和发送端口RTS 往返样本 Round Trip SampleRTS 剩余时间标签SAP 业务接入点 Service Access PointSAP 服务公告协议 Service Advertising ProtocolSAR 分段和重组(子层) Segmentation and ReassemblySDH 同步数字系列 Synchronous Digital HierarchySDLC 同步数据链路控制(协议) Advanced Data Communication Control Procedure SDTV 标准数字电视SDU 业务数据单元 Service Data UnitSIPP 增强的简单因特网协议 Simple Internet Protocol PlusSLIP 串行线路IP Serial Line Interface ProtocolSMDS 交换式多兆比特数据业务 Switched Multimegabit Data ServicesSMF 单模光纤 Single-mode FiberSMT 站点管理 Station ManagementSMTP 简单邮件传输协议 Simple Mail Transfer ProtocolSNA 系统网络体系结构 System Network ArchitectureSNMP 简单网络管理协议 Simple Network Management ProtocolSNR 信噪比 Signal-Noise ratioSONET 同步光纤网络 Synchronous Optical NetworkSTM 同步传输方式 Synchronous Transfer ModeSTP 屏蔽双绞线 Shielded Twisted PairSTS 同步传输信号 Synchronous Transport SignalSVC 交换虚电路 Switched Virtual CircuitSwitch 交换机TCP 传输控制协议 Transmission Control ProtocolTDM 时分多路复用 Time Division MultiplexingTFTP 单纯文件传输协议 Trivial File Transfer protocolTelnet 远程登录协议TIP 终端接口处理机 Terminal Interface ProcessorTP 双绞线 Twisted PairTSAP 传输层服务访问点 Transport Service Access PointUDP 用户数据报协议 User Datagram ProtocolUSB 通用串行总线 Universal Serial BusUTP 非屏蔽双绞线 Unshielded Twisted PairVAN 增值网 Value Added NetworkVBR 可变比特率 Variable Bit RateVCC 虚信道连接 Virtual Channel ConnectionVLAN 虚拟局域网 Virtual LANVLSI 超大规模集成电路VOD 点播图像 Video on DemandVPC 虚路径连接 Virtual Path ConnectionVPI 虚路径标识 virtual path identifierVPN 虚拟专用网络 Virtual Private NetworkVRML 虚拟现实造型语言 Virtual Reality Modeling Language VTP 虚拟隧道协议WAN 广域网 Wide Area NetworkWDM 波分多路复用 Wavelength Division MultiplexingWWW 万维网 World Wide Web。
机械类数控车床外文翻译外文文献英文文献数控
数控加工中心技术开展趋势与对策原文来源：Zhao Chang-ming Liu Wang-ju(C Machining Processand equipment,2002,China)一、摘要Equip the engineering level, level of determining the whole national economy of the modernized degree and modernized degree of industry, numerical control technology is it develop new developing new high-tech industry and most advanced industry to equip (such as information technology and his industry, biotechnology and his industry, aviation, spaceflight, etc. national defense industry) last technology and getting more basic most equipment.Numerical control technology is the technology controlled to mechanical movement and working course with digital information, integrated products of electromechanics that the numerical control equipment is the new technology represented by numerical control technology forms to the manufacture industry of the tradition and infiltration of the new developing manufacturing industry,Keywords:Numerical ControlTechnology, E quipment,industry二、译文数控技术和装备开展趋势与对策装备工业的技术水平和现代化程度决定着整个国民经济的水平和现代化程度，数控技术与装备是开展新兴高新技术产业和尖端工业〔如信息技术与其产业、生物技术与其产业、航空、航天等国防工业产业〕的使能技术和最根本的装备。
数字控制的发展外文文献翻译、中英文翻译、外文翻译
The Development of numerical controlThe evolution of the machine tool industry could hardly be appreciated without a brief review of its birth and growth. John Wilkinson built his metal-cutting boring machine in the eighteenth century, but nearly two centuries of evolution were needed to produce the hydraulic tracer controlled copy mills and lathes. The next stare, automation, was brought about by mass production of automobiles, agricultural implements, household appliances, chemical products, as well as inventory and financial data handling. Three kinds of automation met the needs of society for a major part of the twentieth century. There were:1)Automotive or fixed assembly line automation.2)Process control automation, primarily used in the manufacture of chemical and food products.3)Data processing first developed for processing payrolls, data collection, and inventory control.The Second World War marked the turning point in the ability of the metal-cutting industry to cope with the requirements facing it. The ambitious aircraft and missile projects of the U.S. air force, combined with the demands for commercial jets, made it quite clear that conventional manufacturing could not fulfill future needs.A study of the U.S. government showed that the combined resources of the entire U.S. metal-cutting industry in 1947 could not produce the parts needed by the air force along.Under contract to the U.S. air force，the Parsons Corporation under took the development of a flexible, dynamic manufacturing system, designed to maximize productivity by emphasizing details required to achieve desired accuracies. This system would allow design changes without costly modifications to tooling and fix Turing, and it would fit in to modern, productive manufacturing management for small-to-medium-sized production runs. The Parsons Corporation subcontracted the development of the control system to the Massachusetts Institute of Technology in 1951. A control, which would be applicable to a wide variety of machine tools, woulddrive a slide lead screw through an interface, as instructed by the out put of a computer. MIT met the challenge successfully, and in 1952 demonstrated a Cincinnati Hydrotel milling machine equipped with the new technology, which was named Numerical Control (NC) and used a prepunched tape as the input media. Since 1952, practically every machine tool manufacturer in the Western world has converted part or all of its product to NC.The first NC machines used vacuum tubes, electrical relays, and complicated machine-control interfaces. The second generation of machines utilized improved miniature electronic tubes, and later solid-state circuits. As computer technology improved, NC underwent one of the most rapid changes known in history. The third generation used much improved integrated circuits. Computer hardware became progressively less expensive and more reliable and NC control builders introduced for the first time Read Only Memory (ROM) technology. ROM was typically used for program storage in special-purpose application, leading to the appearance of the computer numerical control (CNC) system. CNC was successfully introduced to practically every manufacturing process. Drilling, milling, and turning to were performed on “machining centre” and “turning centre.” CNC took over glass cutting, pattern making, electrical discharge machining, steel-mill roll grinding, and coordinate measuring electron beam welding，Tube bending, drafting, printed circuit manufacturing, coil winding functional testing, robots, and many other processes.A set of preprogrammed subroutines, named canned cycles, were developed for use in routine operations. They were recorded into the ROMs and remained there even after power was shut off. For the first time, this concept made it possible to read the machining program into memory and to operate the machine from memory. In addition to the advantages of editing, the problems caused by erroneous tape reading disappeared. Along with the many canned cycle option, CNC builders introduced displays for visual editing of part programs in memory. Various in-cycle problems generated alarms and hundreds of diagnostic messages which could be displayed as applicable. Practically every function of the machine was tired into the system and monitored during operation. A constant surface speed control was incorporated andcontinuously anticipated the most efficient spindle speed for the next cut to minimize time lost for spindle acceleration. The conventional linear and circular interpolation in cartesian (rectangular) coordinates were supplemented by polar coordinates and helical internal parameters, created an electronic crash barrier to prevent tool collision the latter group features marked the arrival of high technology to the manufacturing or metal-cutting industry.The improvement in drives was important for the system as the contribution of the microprocessor or the minicomputer.The feed drives, usually known as servos rives, consist of a motor and its control which receives its motion instruction from the CNC. Their performance is essential to the accuracy, reliability, and flexibility of the CNC system.The open-loop system is normally used in simple point-to-point, or positioning systems, although improvements in technology have made it possible to install the system in contouring systems as well.Although many CNC systems still use hydraulic or pulse motors, the DC drives have gained dominance on a much large scale. In most cases, the drive packages are purchased from specialized drive system builders range from 3000 revolution per minute (rpm) to less than 1 rpm without stalling. They develop peak torque capabilities with high slide acceleration and low inertia for optimized system response. Most drive systems offer a choice between transistorized silicone-controlled rectifiers and pulse width modulation over the full range of amplified voltages. These drives can now drive virtually any lead screw. Their high-response inner current loops provide reliable regulation of torque-load disturbance. They can also be built with high-gain preamplifiers to close high-band-width velocity loops. The DC drives provide the answer to the most essential needs of acceleration, deceleration, shopping, and constant velocity, with inherent shaft stiffness for successful operation of the CNC system. The same drive systems actuate robots, transfer, flight simulators, graphic plotters, etc. As these drives are infinitely variable and fully regenerative, they can provide for maximum performance and control over the whole range of the motor. By eliminating gearboxes and clutches the cost of drives for thethird-generation CNC system was reduced substantially.The forth- generation microprocessor CNC incorporated in many cases the controversial bubble memory. The bubbles are magnetic garnet crystals grown on nonmagnetic substrate, ranging in size from 2 to 30 micrometers, and used as non-volatile data storage. Although at this stage it is not competitive in the large computers, the bubble memory is closing the cost gap with disk storage devices. Insensitive to adverse temperature changes, dust, and vibration, the bubble memory has demonstrates superior reliability in shop environment. General Numerical introduce its fourth-generation CNC using bubble memory; however Hitachi, another electronic giant, believe that bubble memory will provide the economical answer to direct numerical control (DNC).Among the strengths of the fourth-generation microprocessor CNC (MCNC) are added part program memory storage, reduction of printed circuit boards, programmable interface, faster memory access, parametric subroutines, and macro capabilities.The system user can now write specific canned cycles directed to particular applications (“user macros”), far more economical and efficie nt than conventional canned cycles. Mathematical calculations with do-loop subroutines using variables can now be incorporated in the part program. The microprocessor controls both computations and motion commands. Thus, following an in-process gagging, an out-of-tolerance condition will be fed back, and the tool offset will be automatically modified to achieve the desired part dimensionsIn addition, the fourth-generation microcomputer CNC system has the ability to control typical robot functions such as loading and unloading parts. Using the teach-in learning mode, the robot can be programmed to change tools or remove chips.The maintenance aspect, however, has not kept up with the system development. Many CNCs and MCNCs are not sufficiently protected against power surges, spikes, or transients, caused by welding equipment, solenoids, motors, or fluorescent lights connected to the same power supply as the CNC. Potential problems are runaways and loss or damage to programs in memory.Many of the maintenance headaches could and probably will be eliminated by phasing out the fast-response, low-energy ( metal oxide version) suppressors or the medium –response, high –energy (isolation transformers) suppressors. The replacement, solid-state suppressors, have a response time on the order of 4-6 nanoseconds, ten times faster than the metal oxide versions (MOVs). Thire energy- dissipating capacity of 16667-J is far higher than the 40-J capacity of the MOVs.Where will technology go from here? To a large extent it develops on the knowledge of the system users and the demands they will pose to the designers and builders of the most practical elements of computer-aided design and computer-aided manufacturing technology.The basic hardware of the CNC consists of the input units , the computing or mathematics unit ,the control unit , and the output units .The function of any input unit is to provide data to the computer in the form of numeric instructions . Present CNC systems are designed to operate with different input media. The most common of these is the punched tape, mainly because it can read inexpensively, is less sensitive to handling, is inexpensive to purchase, and requires less equipment to make and less costly space for data storage . Its disadvantage, however, is that it cannot be reused. The magnetic tape has limited use as a CNC media, it requires sophisticated (expensive) equipment for program recording and reading, and the programmer or operator cannot see the recorded codes and therefore cannot read them. Recording errors are not as obvious and visible as they are in punched tape. Magnetic Tape requires special storage space and must be handled carefully to avoid erasing the program. The typewriter, more commonly known as the keyboard, has limited use because of the operator’s speed. It may not be used for long program input, but is primarily for small programs. Its main use is to edit (correct) programs already in memory or to generate single operations in the Manual Data Input (MDI) mode .The objective here is to introduce the reader to the evolution of the codes we use in our input units to communicate with the CNC computer.数字控制的发展机床工业的发展很难用简单的几句话来形容它的产生和成长。
计算机网络中英文互译,DOC
欢迎共阅计算机网络中英翻译ACK(ACKnowledgement)确认帧ADSL(AsymmetricDigitalSubscriberLine)非对称数字用户线AN(AccessNetwork）接入网ANSI(AmericanNationalStandardsInstitute)美国国家标准协会AP(AccessPoint)接入点API(ApplicationProgrammingInterface)应用编程接口APNIC(AsiaPacificNetworkInformationCenter)亚太网络信息中心ARP（AddressResolutionProtocol）地址解析协议AWT（BNACBR（CCPCSMA/CD(CarrierSenseMultipleAccess／CollisionDetection)载波监听多点接入/碰撞检测CSU/DSU（ChannelServiceUnit/DataServiceUnit)信道服务单元／数据服务单元CTD(CellTransferDelay)信元传送时延DACS(DigitalAccessandCross-connectSystem)数字交接系统DCA数据通信体系结构DCE(DataCircuit-terminatingEquipment)数据电路端接设备DE(DiscardEligibility)丢弃指示DES(DataEncryptionStandard)数据加密标准DHCP(DynamicHostConfigurationProtocol)动态主机配置协议DLCI(DataLinkConnectionIdentifier)数据链路连接标识符DMT(DiscreteMulti-Tone)离散多音（调制）DNS(DomainNameSystem)域名系统DNA数据网络系统结构DSL(DigitalSubscriberLine)数字用户线DSLAM(DSLAccessMultiplexer)数字用户线接入复用器DSSS(DirectSequenceSpreadSpectrum)直接序列扩频DTE(DataTerminalEquipment)数据终端设备DVMRP(DistanceVectorMulticastRoutingProtocol)距离向量多播路由选择协议DWDM(DenseWDM)密集波分复用EGP(ExternalGatewayProtocol)外部网关协议EIA(ElectronicIndustriesAssociation）美国电子工业协会ESS伍FCS(FrameFIFO（FR(FrameGFC（HDSL(HighspeedDSL)高速数字用户线HEC(HeaderErrorControl)首部差错控制HFC(HybridFiberCoax)光纤同轴混合（网）HTML(HyperTextMarkupLanguage)超文本置标语言HTTP(HyperTextTransferProtocol)超文本传送协议IAB(InternetArchitectureBoard)因特网体系结构委员会IAC（InterpretAsCommand）作为命令解释IAHC(InternetInternationalAdHocCommittee）因特网国际特别委员会ICMP（InternetControlMessageProtocol）因特网控制报文协议IDEA(InternationalDataEncryptionAlgorithm)国际数据加密算法IEEE电气和电子工程师协会IESG(InternetEngineeringSteeringGroup)因特网工程指导小组IETF(InternetEngineeringTaskForce)因特网工程部IFS(Inter Frame Space)帧间间隔IGMP(InternetGroupManagementProtocol)因特网组管理协议IGP(InteriorGatewayProtocol)内部网关协议IM(InstantMessaging)即时传信IMAP(InternetMessageAccessProtocol)因特网报文存取协议IMP（InterfaceMessageProcessor)接口报文处理机IP(InternetProtocol）网际协议IR(InfraRed）红外技术IRTF（ISO（ISP（ITU（ITU-T（MIB(ManagementInformationBase)管理信息库MIME(MultipurposeInternetMailExtensions)通用因特网邮件扩充modem调制解调器MOTIF(MessageOrientedTextInterchangeSystem)面向报文的电文交换系统MPEG(MotionPictureExpertsGroup)活动图像专家组标准MPOA(MultiProtocolOverATM)多协议在ATM上运行MPLS(MultiProtocolLabelSwitching)多协议标记交换MRU(MaximumReceiveUnit)最大接收单元MSS(MaximumSegmentSize)最长报文段MTU(MaximumTransferUnit)最大传送单元NAK(NegativeAcKnowlegement)否认帧NAP（NetworkAccessPoint)网络接入点N.ISDN(Narrowband-ISDN)窄带综合业务数字网NAT(NetworkAddressTranslation）网络地址转换NAV(NetworkAl location Vector)网络分配向量NCP(NetworkControlProtocol)网络控制协议NFS(NetworkFileSystem)网络文件系统NGI下一代因特网计划NIA网络适配器NIC(NetworkInterfaceCard)网络接口卡、网卡NII(NationalInformationInfrastructure)国家信息基础结构，国家信息基础设施ODBC（OSF（OSI（PBX（PCR（PCSPDHPDAPDNPDUPERPIRPLCPPLRPMDPPPPPTPPRMPRNPSN分组交换节点PacketSwitchNodePSTN公用电话交换网PublicSwitchedTelephoneNetworkRARP逆向地址解析协议ReverseAddressResolutionProtocolRAS远程访问服务器RFC请求评注RequestforCommentsRMON远程网络管理Router路由器RPC远程过程调用RemoteProcedureCallRSVP资源重复利用协议RTP接收和发送端口RTS往返样本RoundTripSampleRTS剩余时间标签SAP业务接入点ServiceAccessPointSAP服务公告协议ServiceAdvertisingProtocolSAR分段和重组(子层)SegmentationandReassemblySDH同步数字系列SynchronousDigitalHierarchySDLC同步数据链路控制(协议)AdvancedDataCommunicationControlProcedure SDTV标准数字电视SDU业务数据单元ServiceDataUnitSIPP增强的简单因特网协议SimpleInternetProtocolPlusSLIP串行线路IPSerialLineInterfaceProtocolSMDSSMFSMTSMTPSNASNMPSNRSONETSTMSTPSTSSVCTCPTDMTFTPVCC虚信道连接VirtualChannelConnectionVLAN虚拟局域网VirtualLANVLSI超大规模集成电路VOD点播图像VideoonDemandVPC虚路径连接VirtualPathConnectionVPI虚路径标识virtualpathidentifierVPN虚拟专用网络VirtualPrivateNetworkVRML虚拟现实造型语言VirtualRealityModelingLanguageVTP虚拟隧道协议WAN广域网WideAreaNetworkWDM波分多路复用WavelengthDivisionMultiplexing WWW万维网WorldWideWeb。
Robots机器人 中英文翻译
RobotsA robot is an automatically controlled, reprogrammable, multipurpose, mani pulating machine with several reprogrammable axes, which may be either fixed in place or mobile for use in industrial automation applications.The key words are reprogrammable and multipurpose because most single-purpose machines do not meet these two requirements.The term”reprogrammabl e” implies two things:The robot operates according to a written program can b e rewritten to accomdate a variety of manufacturing tasks. The term “multipurp ose” means that the robot can perform many different functions, depending on the program and tooling currently in use.Over the past two decades,the robot has been introduced into industry to perform many monotonous and often unsafe operations. Because robots can per form certain basic tasks more quickly and accurately than humans, they are bei ng increasingly used in various manufacturing industries.Structures of RobotsThe typical structure of industrial robots consists of 4 major components: the manipulator, the end effector, the power supply and control syterm.The manipulator is a mechanical unite that provides motions similar to those of a human arm. It often has a shoulder joint,an elbow and a wrist. It can rotate or slide, strech out and withdraw in every possible direction with certain flexibility.The basic mechanical configurations of the robot manipulator are categorized as Cartesian, cylindrical, spherical and articulated.A robot with a Cartesian geometry can move its gripper to any position within the cube or rectangle defined as its working volum.Cylindrical coordinate robots can move the gripper within a volum that is described by a cylinder. The cylindrical coordinate robot is positioned in the work area by two linear movements in the X and Y directions and one angular rotation about the Z axis.Spherical arm geometry robots have an irregular work envelop. This type of robot has two main variants,vertically articulated and horizontally articulated.The end effector attaches itself to the end of the robot wrist, also called end-of-arm tooling.It is the device intended for performing the designed operations as a human hand can.End effectors are generally custom-made to meet special handling requirements. Mechanical grippers are the most commonly used and are equipped with two or more fingers.The selection of an appropriate end effector for a special application depends on such factors as the payload, enviyonment,reliability,and cost.The power supply is the actuator for moving the robot arm, controlling the joints and operating the end effector. The basic type of power sources include electrical,pneumatic, and hydraulic. Each source of energy and each type of motor has its own characteristics, advantages and limitations. An ac-powered motor or dc-powered motor may be used depending on the system design and applications. These motors convert electrical energy into mechanical energy to power the robot.Most new robots use electrical power supply. Pneumatic actuators have been used for high speed. Nonservo robots and are often used for powering tooling such as grippers. Hydraulic actuators have been used for heavier lift systems, typically where accuracy was not also requied.The contro system is the communications and information-processing system that gives commands for the movements of the robot. It is the brain of the robot; it sends signals to the power source to move the robot arm to a specific position and to the end effector.It is also the nerves of the robot; it is reprogrammable to send out sequences of instructions for all movements and actions to be taken by the robot.A open-loop controller is the simplest for of the control system, which controls the robot only by foolowing the predetermined step-by-step instructions.This system dose not have a self-correcting capability.A close-loop control system use feedback sensors to produce signals that reflct the current states of the controed objects. By comparing those feedback signals with the values set by the programmer, the close-loop controller can conduct the robot to move to the precise position and assume the desired attitude, and the end effector can perform with very high accuracy as the close-loop control system can minimize the discrepancy between the controlled object and the predetermined references.Classification of RobotIndustrial robots vary widely in size,shape, number of axes,degrees of freedom, and design configuration. Each factor influence the dimensions of the robot’s working envelop or the volume of space within which it can move and perform its designated task. A broader classification of robots can been described as below.Fixed-and Variable-Sequence Robots. The fixed-sequence robot (also called a pick-and place robot) is programmed for a specific sequence of operations. Its movements are form point to point, and the cycle is repeated continuously.The variable-sequence robot can be programmed for a specific sequence of operations but can be programmed to perform another sequence of operation.Playback Robot. An operator leads or walks the playback robot and its end effector through the desired path. The robot memorizes and records the path and sequence of motions and can repeat them continually without any further action or guidance by the operator.Numerically Controlled Robot. The numerically controlled robot is programmed and operated much like a numerically controlled machine. The robot is servocontrolled by digital data, and its sequence of movements can be changed with relative ease.Intelligent Robot. The intelligent robot is capable of performing some of the functions and tasks carried out by huanbeings.It is equipped with a variety of sensors with visual and tactile capabilities.Robot ApplicationsThe robot is a very special type of productin tool; as a result, the applications in which robots are used are quite broad. These applications can be grouped into three categories: material processing, material handling and assembly.In material processing, robots use tools to process the raw material. For example, the robot tools could include a drill and the robot would be able to perfor drilling operaytions on raw material.Material handling consists of the loading, unloading, and transferring of workpieces in manufacturing facilities. These operations can be performed relatively and repeatedly with robots, thereby improving quality and scrap losses.Assembly is another large application area for using robotics. An automatic assembly system can incorporate automatic testing, robot automation and mechanical handling for reducing labor costs, increasing output and eliminating manual handling concers.机器人机器人是一种自动控制的、可重复编程的、多功能的、由几个可重复编程的坐标系来操纵机器的装置，它可以被固定在某地，还可以是移动的以在工业自动化工厂中使用。
建环毕业翻译(中英文对照)
外文翻译中文空调工作过程和节能技术的研究摘要：一台空调基本上是没有被隔离的箱子的一个冰箱。
它象氟里昂一样利用冷媒的蒸发提供冷却.在一台空调里氟里昂蒸发循环的过程和冰箱里的相同。
关键词：水塔、改变气候、压缩机、节能当外面的温度开始上升时，很多人寻找室内的空调的极好的安慰。
象水塔和电源线一样，空调是我们每天看见但是很少注意的那些东西之一。
它将不是很高兴的知道这些不可缺少的机器怎样运转他们的魔术吗？在这篇文章里，我们将检查空调–从微观到宏观–以使你对你所看见的知道得更多！低温的各个方面.空调的定型是各种尺寸，冷却能力和价格。
我们经常看见的一种类型是窗式空气调节器.窗式空气调节器是冷却一个小的区域的一种容易和节约的方法。
居住在郊区的地区的大多数人通常在他们的后院有这些中之一：如果你住在一座公寓大厦里，这或许是一个熟悉的情景：大多数商业和办公楼在他们的屋顶上有冷凝装置，并且当你飞到上空时,仓库和商业区可能让人把10 或者20 套冷凝装置隐藏在他们的屋顶上：当你徘徊在很多医院,大学和办公室联合企业的周围时，你会找到连接空气调节系统的大的冷却塔：即使这些机器中的每个都有一个相当清楚的外表，他们全部以相同的原理工作。
让我们近距离地看一下。
基本的想法，一台空调基本上是没有被隔离的箱子的一个冰箱。
它象氟里昂一样利用冷媒的蒸发提供冷却.在一台空调里氟里昂蒸发循环的过程和冰箱里的相同。
根据在线梅里厄姆织工字典,氟里昂一般“用于任何各种各样的调节器”。
根据在线梅里厄姆织工字典，氟里昂一般”用于作为致冷剂和作为气溶胶推进者使用的任何各种各样的不易燃的碳氟化合物。
”这就是在一台空调里的蒸发循环是怎么样工作（看出冰箱怎样为关于这个系列的完整的细节工作）：1。
压缩机压缩低温的氟里昂气体，产生高温,高压氟里昂气体.2. 这种高温气体通过一套线圈，因此它能使它的热消散, 并且它凝结成一种液体。
3。
氟里昂液体充满一个膨胀阀, 并且在这个过程里蒸发变得低温，低压氟里昂气体。
【机械类文献翻译】CADCAM和数字控制
英文翻译学生姓名：所在院系：所学专业：导师姓名：完成时间：CAD/CAM和数字控制一、计算机辅助设计及应用在讲述CAD的基本原理之前，先说说它的简史是比较合适的。
CAD是计算机时代的产品。
它从早期的计算机绘图系统发展到现在的交互式计算机图形学。
两个这样的系统包括：麻省理工学院的Sage Project 及Sketchpad。
Sage Project 旨在开发CRT显示器及操作系统。
Sketchpad是在Sage Project下发展起来的。
CRT显示和光笔输入用于与系统进行交互操作。
CAD与初次出现的NC和APT （自动编程工具）碰巧同时问世。
后来，X—Y绘图仪作为计算机绘图的标准，除了绘图笔被NC机床上的主轴的刀具替代之外。
开始，CAD系统仅仅是一个带有内臵设计符号的绘图编辑器。
供用户使用的几何元素只是直线、圆弧以及两者的组合。
自由曲线及其曲面的发展，如昆氏嵌面、贝塞尔嵌面以及B样条曲线，使CAD系统可用于复杂曲线与曲面设计。
三维CAD系统允许设计者步入三维设计空间。
由于一个三维模型包含了NC刀具路径编程所需要的足够信息，所以能够开发CAD与NC之间联系的系统。
所谓交钥匙的CAD/CAM系统便是根据这一个概念开发的，并从20世纪70年代至80年代流行起来。
20世纪70年代，三维实体建模的发明标志着CAD一个新时代的开始。
过去的三维线框模型仅用其边界来表达一个物体。
这在某种意义上是含糊的，一个简单的模型可能有几种解释。
同时也无法获得一个模型的体积信息。
实体模型包含完整的信息，因此，它们不仅可用于生成工程图，而且也可以在同一模型上完成工程分析。
后来，开发了许多商业系统和研究系统。
这些系统中相当多的是基于PADL和BUICD系统。
尽管它们在表达上是强有力的，但仍然存在许多缺陷。
例如，这种系统要有极强的计算能力和内存需求，非常规的物体建模实体建模开始介入设计环境。
今天实体模型的应用如同绘图和线框模型应用一样普通。
数字控制外文文献翻译、中英文翻译
Numerical controlNumerical control of machine tools may be defined as a method of automation in which various functions of machine tools are controlled by letters, numbers and symbols. Basically a NC machine runs on a program fed to it. The program consists of precise instructions about the manufacturing methodology as well as the movements. Fox example, what tool is to be used, at what speed, at what feed and to move from which point to which point in what path, all these instructions are given. Since the program is the controlling point for product manufacture, the machine becomes versatile and can be used for any part. All the functions of an NC machine tool are therefore controlled electronically, hydraulically or pneumatically.In NC machine tools one or more of the following functions may be automatic:(i)Starting and stopping of the machine tool spindle.(ii)Controlling the spindle speed.(iii)Positioning the tool tip at desired locations and guiding it along. Desired paths by automatic control of the motion of slides.(iv)Controlling the rate of movement of tool tip.(v)Changing of tools in the spindle.Initially the need of NC machines was felt for machining complex shaped small batch components as those belonging to an aircraft. However, this spectrum currently encompasses practically all activities of manufacturing, in particular capital goods and white goods. Thus the range covered is very wide. Besides machining with which we are concerned, NC has been used in a variety of manufacturing situations. The majority of applications of NC are in metal cutting machine tools such as milling machines, lathes, drilling machines, grinding machines and gear generating machines. Besides a number of metal forming machine tools such as presses, flame cutting machines, pipe bending and forming machines, folding and shearing machines also use NC for their program control. The inspection machines called Co-ordinate Measuring (CMM) are also based on NC. Lastly the robots basically may be material handling units, but their control principles are very close to the NC. Besides these applications listed for manufacturing, other applications such as filament winding or assembly machines based on the NC principles can also be seen in the industry.NC machines have been found suitable for the following:(i)Parts having complex contours, that cannot be manufactured by conventional machinetools.(ii)Small lot production, often for even single (one off) job production, such as for prototyping, tool manufacturing, etc.(iii)Jobs requiring very high accuracy and repeatability.(iv)Jobs requiring many set-ups and/or when the set-ups are expensive.(v)Parts that are subjected to frequent design changes and consequently require more expensive manufacturing methods.(vi)The inspection cost, which is a significant portion of the total manufacturing cost.One or more of the above considerations would justify the processing of a part by an NC machine tool.Numerical Control is superior to conventional manufacturing in a number of ways. The superiority comes because of the programmability. These are as follows:(i) Parts can be produced in less time and therefore are likely to be less expensive. The idle(non-cutting) time is reduced to minimum. This of course depends on the way the part program for the part is written. The endeavour of the machine tool builder is to provide a facility whereby the non-cutting time can be brought to the minimum. It is possible to reduce the non-productive time in NC machine tools in the following ways:(a)by reducing the number of set-ups(b)by reducing set-up time(c)by reducing workpiece-handling time(d)by reducing tool-changing time.These make machines highly productive.(ii)Parts can be produced more accurately even for smaller batches. In conventional machine tools, precision is largely determined by human skill, NC machines, because of automation and the absence of interrelated human factors, provide much higher precision and thereby promise a product of consistent quality for the entire batch.(iii)The operator involvement in part manufacture is reduced to a minimum and as a result less scrap is generated due to operator errors. No operator skill is needed, except in setting up of the tools and the work. Even here, the set-up has been simplified to a great extent.(iv)Since the part program takes care of the geometry generated, the need for expensive jigs and fixtures is reduced or eliminated, depending upon the part geometry. Even when a fixture is to be used, it is very simple compared to a conventional machine tool. It is far easier to make and store part program (tapes).(v)Inspection time is reduced, since all the parts in a batch are identical, provided proper care is taken about tool compensations and tool wear in part program preparation and operation. With the use of inspection probes in the case of some advanced CNC controllers, the measurement function also becomes part of the program.(vi)The need for certain types of form tools is completely eliminated in NC machines. This is because the profile generated can be programmed, even if it involves three dimensions. (vii)Lead times needed before the job can be put on the machine tool are reduced to a great extent, depending upon the complexity of the job. More complex jobs may require fixtures or templates if they are to be machined in conventional machine tools, which can be reduced to a large extent.(viii)CNC machining centers can perform a variety of machining operations that have to be carried out on several conventional machine tools, thus reducing the number of the machine tools on the shop floor. This would save floor space and result in less lead-time in manufacture. This would also result in an overall reduction in production costs.(ix)The set-up times are reduced, since the set-up involves simple location of the datum surface and position. Further, the number of the set-ups needed can also be reduced. All this translates into lower processing times. A component can be fully machined in a single machining center or turning center, each of which having wider machining capabilities. In conventional manufacture if the part has to be processed through a number of machine tools which are located in different departments, the time involved in completion and the resultant in process inventory would be large. This would be greatly eliminated by the use of NC machine tools.数字控制机床数字控制是一种由数字和符号控制完成机床各种功能的自动化方法。
[住宅小区}配电策画外文文献翻译中英文
外文文献翻译(含：英文原文及中文译文)译文字数：3700多字文献出处：J . [J], 2016, 2(3):14-21英文原文J. l0 a , . , , 't 's , , , a , .: , , ,, : , , . , , , , , , . . 20 , . . , a , , . , a a . , a . , . , . ,, , , , . , ..'s . 2500 ., . ; ; a .a . , . . .a , . , , , .. , .,(), , , , , ., ., () , , , , s , s e . , , .a ., . .a , a , ., , , , . , . () ’s ., , a . , ,., a , n , , ., , .. . , , , . , , , , , . , .. . , ., , , , , .l0 . l0 , , . .. l0 . , a .,l0 . . , ., , . ., . a , , I0 ... l0 a , . , , 't 's . , , , a , . , .., l0 . , ., , . . ,, . ., , , . , l0 .a , , .. .a .a . .. A . ( ) . , . , () . , . .中文译文住宅小区配电设计J摘要电力系统的基本功能是向客户输送电力。
10配电网是将电力供应与用于工业，商业和日常生活中的电力相连接的关键点。
对于电力而言，所有用户都希望以最高的可靠性支付最低的价格，但不要认为它在经济和可靠性的共存方面是自相矛盾的。
为了提高供电网络的可靠性，我们必须增加网络建设的投资成本但是，如果提高网络建设可靠性的成本，但如果减少的损失是在关闭的时候，这种建设的投资将是毫无价值的，小于增加的改善投资通过计算电网投资和停电带来的损失，找出投资与亏损之间最具经济性的平衡点。
智能控制系统毕业论文中英文资料对照外文翻译文献
controlled object, as intelligent load monitoring test, is the use of single-chip I / O port output signal of relay control, then the load to control or monitor, thus similar to any one single chip control system structure, often simplified to input part, an output part and an electronic control unit ( ECU )
information, which can more effectively assist the security personnel to deal with the crisis, and minimize the damage and loss, it has great practical significance, some risk homework, or artificial unable to complete the operation, can be used to realize intelligent device, which solves a lot of artificial can not solve the problem, I think, with the development of the society, intelligent load in all aspects of social life play an important reuse.
外文文献翻译可编程逻辑控制器PLC
百度文库让每个人平等地捉升口我可编程逻辑控制器PLC外文文献翻译(含：英文原文及中文译文)文献出处：Kinna D. Programmable Logic Controllers (PLC) [J]. Fusion Engineering & Design, 2015, 2(12):72-83. 英文原文Programmable Logic Controllers (PLC)Kinna Dari1MotivationProgrammable Logic Controllers (PLC), a computing device invented by Richard E. Morley in 196& have been widely used in industry including manufacturing systems, transportation systems, chemical process facilities, and many others. At that time, the PLC replaced the hardwired logic with soft-wired logic or so-called relay ladder logic (RLL), a programming language visually resembling the hardwired logic, and reduced thereby the configuration time from 6 months down to 6 days [Moody and Morley, 1999].Although PC based control has started to come into place, PLC based control will remain the technique to which the majority of industrial applications will adhere due to its higher performance, lower price, and superior reliability in harsh environments Moreover, according to a studyon the PLC market of Frost and Sullivan [1995], an increase of the annual sales volume to 15 million PLCs per year with the hardware value of more 百度文库让每个人平等地捉升口我than 8 billion US dollars has been predicted, though the prices ofcomputing hardware is steadily dropping. The inventor of the PLC, Richard E Morley, fairly considers the PLC market as a 5-billion industry at the present time.In general, the productivity in generating PLC is far behind compared to other domains, for instance, VLSI design, where efficient computer aided design tools are in practice - Existent software engineering methodologies are not necessarily applicable to the PLC based software design because PLC-programming requires a simultaneous consideration of hardware and software - The software design becomes, thereby, more and more the major cost driver. In many industrial design projects, more than 50% of the manpower allocated for the control system design and installation is scheduled for testing and debugging PLC programs [Rockwell, 1999].PLCs (programmable logic controllers) are the control hubs for a wide variety of automated systems and processes. They contain multiple inputs and outputs that use transistors and other circuitry to simulate switches and relays to control equipment. They are programmable via software interfaced via standard computer interfaces and proprietary languages and network options -Programmable logic controllers I/O channel specifications include total number of points, number of inputs and outputs, ability to expand, and maximum number of channels - Number of points is the sum of the inputs百度文库让每个人平等地捉升口我and the outputs - PLCs may be specified by any possible combination of these values. Expandable units may be stacked or linked together to increase total control capacity. Maximum number of channels refers to the maximum total number of input and output channels in an expanded systemPLC system specifications to consider include scan time, number of instructions, data memory, and program memory. Scan time is the time required by the PLC to check the states of its inputs and outputs. Instructions are standard operations (such as math functions) available to PLC software. Data memory is the capacity for data storage - Program memory is the capacity for control software.Programmable logic controllers use a variety of software programming languages for control. These include IEC 61131-3, sequential function chart (SFC), function block diagram (FBD), ladder diagram (LD), structured text (ST), insti-uction list (IL), relay ladder logic (RLL), flow chart, C, and Basic. The IEC 61131-3 programming environment provides support for five languages specified by the global standard: Sequential Function Chart, Function Block Diagram, Ladder Diagram, Structured Text, and Instruction List. This allows for multi-vendor compatibility and multi-language programming. SFC is a graphical language that provides coordination of program sequences, supporting alternative sequence selections and parallelsequences. FBD uses a broad function library to build complex procedures百度文库让每个人平等地捉升口我in a graphical format - Standard math and logic functions may be coordinated with customizable communication and interface functions. LD is a graphic language for discrete control and interlocking logic. It is completely compatible with FBD for discrete function control. ST is a text language used for complex mathematical procedures and calculations less well suited to graphical languages. IL is a low-level language similar to assembly code - It is used in relatively simple logic instructions. RelayLadder Logic (RLL), or ladder diagrams, is the primary programming language for programmable logic controllers (PLCs) - Ladder logic programming is a graphical representation of the program designed to look like relay logic. Flow Chart is a graphical language that describes sequential operations in a controller sequence or application. It is used to build modular, reusable function libraries.C is a high level programming language suited to handle the most complex computation, sequential, and data logging tasks. It is typically developed and debugged on a PC. BASIC is a high level language used to handle mathematical, sequential, data capturing and interface functions・2ResumeA PLC (programmable Logic Controller) is a device that was invented toreplace the necessary sequential relay circuits for control. The PLC works by looking at its input and depending upon their state, turning on/off its百度文库让每个人平等地捉升口我outputs - The user enters a program, usually via software or programmer, which gives the desired results.PLC is used in many u real world H applications. If there is industry present, chance are good that there is a PLC present. If you are involved in machining, packing, material handling, automated assembly or countless other industries, you are probably already using them. If you are not, you are wasting money and time- Almost any application that needs some typeof electrical control has a need for a PLC -For example, let's assume that when a switch turns on we want to turn a solenoid on for 5 second and then turn it off regardless of how long the switch is on for. We can do this with a simple external timer. But what if the process included 10 switches and solenoids? We should need 10 external times What if the process also needed to count how many times the switch individually turned on? We need a lot of external counters.As you can see the bigger the process the more of a need we have for a PLC - We can simply program the PLC to count its input and turn the solenoids on for the specified time. We will take a look at what is considered to be the H top20" PLC instructions. It can be safely estimated that with a firm understanding of these instructions one can solve more than 80% of the applications in existence・百度文库让每个人平等地捉升口我Of course we will learn more than just this instruction to help you solve almost ALL potential PLC applications.The PLC mainly consists of a CPU, memory areas, and appropriatecircuits to receive input/output data. We can actually consider the PLC to be a box full of hundreds or thousands of separate relay, counters, times and data storage locations, Do these counters, timers, etc. really exist? No, theydon't “physically" exist buE y r simi d atedi and be considered software counters, timers, etc.・These internal relays are simulated through bit locations in registers.What does each part do? Let me tell you.Input RelaysThese are connected to the outside world. They physically exist and receivesignals from switches, sensors. Typically they are not relays but rather they are transistors・Internal Utility RelaysThese do not receive signals from the outside world nor do they physicallyexist, they are simulated relays and are what enables a PLC to eliminate external relays - There are also some special relays that are dedicated to performing only one task. Some are always on while some are always off. Some are on only once during power-on and are typically used for initializing data that was stored.Counters百度文库让每个人平等地捉升口我These again do not physically exist. They are simulated counters and they can be programmed to count pulses. Typically these counters can count up, down or both up and down. Since they are simulated, they are limited in their counting speed - Some manufacturers also include high-speed counters that are hardware based. We think of these as physically existing. Most times these counters can count up, down or up and down.TimersThese also do not physically exist. They come in many varieties and increments. The most common type is an on-delay type. Others include off- delays and both retentive and non-retentive types - Increments vary from1ms through Is.Output RelaysThere are connected to the outside world. They physically exist and send on/off signals to solenoids, lights,etc. They can be transistors, relays, or triacs depending upon the model chosen. Data StorageTypically there are registers assigned to simply store data. They are usually used as temporary storage for math or data manipulation. They can also typically be used to store data when power is removed form the PLC-Upon power-up they will still have the same contents as before power was moved. Very convenient and necessary!A PLC works by continually scanning a program - We can think ofthis scan cycle as consisting of 3 important steps. There are typically more than 3 but we can focus on the important parts and not worry about the others, Typically the others are checking the system and updating the current百度文库让每个人平等地捉升口我internal counter and timer values -Step 1 is to check input status, First the PLC takes a look at each input to determine if it is on off. In other words, is the sensor connected to the first input on? How about the third...It records this data into its memory to be used during the next step.Step 2 is to execute program. Next the PLC executes your program one instruction at a time. Maybe your program said that if the first input was on then it should turn on the first output. Since it already knows which inputs are on/off from the previous step, it will be able to decide whether the first output should be turned on based on the state of the first input. It will store the execution results for use later during the next step.Step 3 is to update output status. Finally the PLC updates the status the outputs. It updates the outputs based on which inputs were on during the first step and the results executing your program during the second step. Based on the example in step 2 it would now turn on the first output because the first input was on and your program said to turn on the first output when this condition is true.After the third step the PLC goes back to step one repeats the stepscontinuously. One scan time is defined as the time it takes to execute the 3 steps continuously. One scan time is defined as the time it takes to execute the 3 steps listed above - Thus a practical system is controlled to perform specified operations as desired.百度文库让每个人平等地捉升口我3PLC StatusThe lack of keyboard and other input-output devices is very noticeable on a PLC. On the front of the PLC there are normally limited status lights. Common lights indicate.These lights are normally used for debugging. Limited buttons will also be provided for PLC hardware. The most common will be a run/program switch that will be switched to program when maintenance is being conducted, and back to run when in production. This switch normally requires a key to keep unauthorized personnel from altering the PLC program or stopping execution. A PLC will almost never have an on-off switch or reset button on the front. This needs to be designed into the remainder of the system.The status of the PLC can be detected by ladder logic also. It is common for programs to check to see if they are being executed for the first time, as shown in Figure 1. Hie first seal input will be tme on the very first time the ladder logic is scanned, but false on every other scan. In this case the address for 'first scan' in a PLC-5 is ,S2:1/14\ With the logic in the example the first scan will seal on light ；until , cleaF is turned on. So thelight will turn on after the PLC has been turned on, but it will turn off and stay off after 'cleaF is tiinied on.百度文库让每个人平等地捉升自我4Memory TypesThere are a few basic types of computer memory that are in use today.RAM (Random Access Memory) - this memory is fast, but it will lose its contents when power is lost, this is known as volatile memory. Every PLC uses this memory for the central CPU when running the PLC -ROM (Read Only Memory) - this memory is permanent and cannot be erased. It is often used for storing the operating system for the PLC -EPROM (Erasable Programmable Read Only Memory) - this is memory that can be programmed to behave like ROM, but it can be erased with ultraviolet light and reprogrammed・EEPROM (Electronically Erasable Programmable Read Only Memory) -This memory can store programs like ROM - It can be programmed and erased using a voltage, so it is becoming more popular than EPROMs.All PLCs use RAM for the CPU and ROM to store the basic operating system for the PLC - When the power is on the contents of the RAM will be kept, but the issue is what happens when power to the memory is lost. Originally PLCvendors used RAM with a battery so that the memory contents would not be lost if the power was lost. This method is still in use, but is losing favor. EPROMs have also been a popular choice for programming PLCs. The EPROM is programmed out of the PLC, and then placed in the PLC. When the PLC is turned on the ladder logic program on10百度文库让每个人平等地捉升口我the EPROM is loaded into the PLC and run. This method can be very reliable, but the erasing and programming technique can be time consuming - EEPROM memories are a permanent part of the PLC, and programs canbe stored in them like EPROM. Memory costs continue to drop, and newer types (such as flash memory) are becoming available, and these changes will continue to impact PLCs.5Objective and Significance of the ThesisThe objective of this thesis is to develop a systematic software design methodology for PLC operated automation systems. The design methodology involves high-level description based on state transition models that treat automation control systems as discrete event systems, a stepwise design process, and set of design rules providing guidance and measurements to achieve a successful design. The tangible outcome of this research is to find a way to reduce the uncertainty in managing the control software development process,that is, reducing programming and debugging time and their variation, increasing flexibility of the automation systems, and enabling software reusability through modularity. The goal is to overcome shortcomings of current programming strategies that are based on the experience of the individual software develope 匚中文译文可编程逻辑控制器(PLC)吉娜达尔11百度文邮-让每个人平零地捉开口我1动机可编程逻辑控制器（PLC）是Richard E. Morley于1968年发明的计算设备，己广泛应用于工业领域，包括制造系统，运输系统，化学处理设施等等。
(完整word版)单片机外文文献翻译
中文资料原文单片机单片机也被称为微控制器（Microcontroller Unit），常用英文字母的缩写MCU表示单片机，它最早是被用在工业控制领域。
单片机由芯片内仅有CPU的专用处理器发展而来。
最早的设计理念是通过将大量外围设备和CPU集成在一个芯片中，使计算机系统更小，更容易集成进复杂的而对体积要求严格的控制设备当中。
INTEL的Z80是最早按照这种思想设计出的处理器，从此以后，单片机和专用处理器的发展便分道扬镳。
早期的单片机都是8位或4位的。
其中最成功的是INTEL的8031，因为简单可靠而性能不错获得了很大的好评。
此后在8031上发展出了MCS51系列单片机系统。
基于这一系统的单片机系统直到现在还在广泛使用。
随着工业控制领域要求的提高，开始出现了16位单片机，但因为性价比不理想并未得到很广泛的应用。
90年代后随着消费电子产品大发展，单片机技术得到了巨大提高。
随着INTEL i960系列特别是后来的ARM系列的广泛应用，32位单片机迅速取代16位单片机的高端地位，并且进入主流市场。
而传统的8位单片机的性能也得到了飞速提高，处理能力比起80年代提高了数百倍。
目前，高端的32位单片机主频已经超过300MHz，性能直追90年代中期的专用处理器，而普通的型号出厂价格跌落至1美元，最高端[1]的型号也只有10美元。
当代单片机系统已经不再只在裸机环境下开发和使用，大量专用的嵌入式操作系统被广泛应用在全系列的单片机上。
而在作为掌上电脑和手机核心处理的高端单片机甚至可以直接使用专用的Windows和Linux操作系统。
单片机比专用处理器更适合应用于嵌入式系统，因此它得到了最多的应用。
事实上单片机是世界上数量最多的计算机。
现代人类生活中所用的几乎每件电子和机械产品中都会集成有单片机。
手机、电话、计算器、家用电器、电子玩具、掌上电脑以及鼠标等电脑配件中都配有1-2部单片机。
而个人电脑中也会有为数不少的单片机在工作。
中英文翻译--工业机器人-精品
Industrial robotsThere are variety of definitions of the term robot. Depending on the definition used, the number of robot installations worldwide varies widely。
Numerous single—purpose machines are used in manufacturing plants that might appear to be robots。
These machines are hardwried to perform a single function and cannot be reprogrammed to preform a different function. Such single-purpose machines do not fit the definition for industrial robots that is becoming widely accepted.this definition was developed by the Robot Institute of America.A robot is a reprogrammable multifunctional mainipulator designed to move material，parts, tools，or specialized devices through variable programmed motions for the performance of a variety of tasks.Note that this definition contains the words reprogrammable and multifunctional。
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外文资料Numerical ControlOne of the most fundamental concepts in the area of advanced manufacturing technol-ogies is Numerical Control(NC). Prior to the advent of NC, all machine tools were manually operated and controlled. Among the many limitations associated with manual control machine tools. Perhaps none is more prominent than the limitation of operator skills. With manual control, the quality of the product are directly related to and limited to the skills of the operator. Numerical Control represented the first major step away from human control of machine tools.Numerical Control means the control of machine tools and other manufacturing systems through the use of prerecorded, written symbolic instructions. Rather than operating a machine tool. For a machine tool to be numerically controlled, it must be interfaced with a device for accepting and decoding the programmed instructions, known as a reader.Numerical Control was developed to overcome the limitation of human operators, and it has done so. Numerical Control machines are more accurate than manually operated machines,they can produce parts more uniformly, they are faster, and the long-run tooling costs are lower. The development of NC led to the development of several other innovations in manufacturing technology:(1) Electrical discharge machining.(2) Laser cutting.(3) Electron beam welding.Numerical Control has also made machine tools more versatile than their manually operated predecessors. An NC machine tool can automatically produce a wide variety of parts, each involving an assortment of widely varied and comples machining processes. Numerical Control has allowed manufacturers to undertake the production of products that would not have been feasible from an economic perspective using manually controlled machine tools and processes.Like so many advanced technologies, NC was born in the laboratories of the Massachusetts Institute of Technology. The concept of NC was developed in the early 1950s with funding provided by the U.S. Air Force. In its earliest stages, NC machines were able to make straight cuts efficiently and effectively.However, curved paths were a problem because the machine tool han to be programmed to undertake a series of horizontal and vertical steps to produce a curve. The shorter the straight lines making up the steps had to be calculated.This problem led to the development in 1959 of the Auto matically Programmed Tools (APT) language. This a special programming language for NC that uses statements similar to English language to define the part geometry, descrile the cutting similar to English language to define the part geometry, describe the cutting tool configuration, and specify the necessary motions. The development of the APT language was a major step forward in the further development of NC technology. The original NC systems were vastly different from those used today. The machines had hardwired logic circuits. The instructional programs were written on punched paper, which was later to be replaced by magnetic plastic tape. Atape reader was used to interpredt the instructions written on the tape for the machine. Together, all of this represented a giant step forward in the control of machine tools. However, there were a number of problems with NC at this point in its development.A major proble was the fragility of the punched paper tape medium. It was common for the paper tape containing the programmed instructions to break or tear during a machjining process. This problem was exacerbated by the fact that each successive time a part was produced on a machine tool, the paper tape carrying the programmed instructions had to be rerun through the reader. If it was necessary to produce 100 separate times. Fragile paper tapes simply could not withstand the rigors of a shop floor environment and this kind of repeated use.This led to the development of a special magnetic plastic tape. Whereas the paper tape carried the programmed instructions as a series of holes punched in the tape. The plastic tape carried the instructions as a series of magnetic dots. The plastic tape was much stronger than the paper tape, which solved the problem of frequent tearing andbreakage. However, it still left two other problems.The most important of these was that it was difficult or impossible to change the instructions entered on the tape. To make even the most minor adjustments in aprogram of instructions, it was necessary to interrupt machining operations and make a new tape. It was also still necessary to run the tape through the reader as many times as there were solved the problems of NC associated with punched paper and plastic tape.The development of a concept known as Direct Numerical Control(DNC) solved the paper and plastic tape problems associated with Numerical Control by simply eliminating tape as the medium for carrying the programmed instructions. In Direct Numerical Control, machine tool are tied, via a data transmission linkage. Direct Numerical Control represented a major step forward over punched tape and plastic tape. However, it is subject to the same limitations as all technologies that depend on a host computer. When the host computer goes down, the machine tools also experience downtime. This problem led to the development of Computer Numerical Control.The development of the microprocessor allowed for the development of Programmable Logic Controller (PLC) and microcomputer. These two technologies allowed for the development of Computer Numerical Control (CNC). With CNC, each machine tool has a PLC or a microcomputer that serves the same purpose. This allows programs to be input and stored at each individual machne tool. It also allows programs to be developed offline and downloaded at the individual machine tool. CNC solved the problems associated with downtime of the host computer, but it introduced another problem known as data management. The same program might be loaded on ten different microcomputers with no communication among them. This problem is in the process of being solved by lacal area networks that connect microcomputers for better data management.中文译文数字控制先进制造技术中的一个最基本的概念是数字控制（NC）。