數(shù)控編程工藝類外文文獻翻譯@中英文翻譯@外文翻譯

Numerical Control One of the most fundamental concepts in the area of advanced manufacturing technologies is numerical control (NC).Prior to the advent of NC, all machine tools were manual 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 is directly related to and limited to the skills of the operator . Numerical control represents the first major step away from human control of machine tools. Numerical control means the control of machine tools and other manufacturing systems though the use of prerecorded, written symbolic instructions. Rather than operating a machine tool, an NC technician writes a program that issues operational instructions to the machine tool, For a machine tool to be numerically controlled , it must be interfaced with a device for accepting and decoding the p2ogrammed instructions, known as a reader. Numerical control was developed to overcome the limitation of human operator , 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 par4s , each involving an assortment of 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 had to be programmed to undertake a series of horizontal and vertical steps to produce a curve. The shorter is the straight lines making up the step ,the smoother is 4he curve . Each line segment in the steps had to be calculated. This problem led to the development in 1959 of the Automatically Programmed Tools (APT) language for NC that uses statements 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 system were vastly different from those used punched paper , which was later to replaced by magnetic plastic tape .A tape reader was used to interpret the instructions written on the tape for the machine .Together, all /f this represented 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 problem was the fragility of the punched paper tape medium . It was common for the paper containing the programmed instructions to break or tear during a machining 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 rerun thought the reader . If it was necessary to produce 100 copies of a given part , it was also necessary to run the paper tape thought the reader 100 separate times . Fragile paper tapes simply could not withstand the rigors of shop floor environment and this kind of repeated use. This led to the development of a special magnetic tape . Whereas the paper tape carried the programmed instructions as a series of holes punched in the tape , theThis 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 a program of instructions, it was necessary to interrupt machining operations and make a new tape. It was also still necessary to run the tape thought the reader as many times as there were parts to be produced . Fortunately, computer technology become a reality and soon solved the problems of NC, associated with punched paper and plastic tape. The development of a concept known as numerical control (DNC) solve 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 tools are tied, via a data transmission link, to a host computer and fed to the machine tool as needed via the data transmission linkage. Direct numerical control represented a major step forward over punched tape and plastic tape. However ,it is subject to the same limitation as all technologies that depend on a host computer. When the host computer goes down , the machine tools also experience down time . This problem led to the development of computer numerical control. The development of the microprocessor allowed for the development of programmable logic controllers (PLC) and microcomputers . 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 machine tool. CNC solved the problems associated 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 local area networks that connectDigital Signal Processors There are numerous situations where analog signals to be processed in many ways, like filtering and spectral analysis , Designing analog hardware to perform these functions is possible but has become less and practical, due to increased performance requirements, flexibility needs , and the need to cut down on development/testing time .It is in other words difficult pm design analog hardware analysis of signals. The act of sampling an signal into thehat are specialised for embedded signal processing operations , and such a processor is called a DSP, which stands for Digital Signal Processor . Today there are hundreds of DSP families from as many manufacturers, each one designed for a particular price/performance/usage group. Many of the largest manufacturers, like Texas Instruments and Motorola, offer both specialised DSPs for certain fields like motor-control or modems ,and general high-performance DSPs that can perform broad ranges of processing tasks. Development kits an software are also available , and there are companies making software development tools for DSPs that allows the programmer to implement complex processing algorithms using simple “drag n drop” methodologies. DSPs more or less fall into two categories depending on the underlying architecture-fixed-point and floating-point. The fixed-point devices generally operate on 16-bit words, while the floating-point devices operate on 32-40 bits floating-point words. Needless to say , the fixed-point devices are generally cheaper . Another important architectural difference is that fixed-point processors tend to have an accumulator architecture, with only one “general purpose” register , making them quite tricky to program and more importantly ,making C-compilers inherently inefficient. Floating-point DSPs behave more like common general-purpose CPUs ,with register-files. There are thousands of different DSPs on the market, and it is difficult task finding the most suitable DSP for a project. The best way is probably to set up a constraint and wishlist, and try to compare the processors from the biggest manufacturers against it. The “big four” manufacturers of DSPs: Texas Instruments, Motorola, AT&T and Analog Devices. Digital-to-analog conversion In the case of MPEG-Audio decoding , digital compressed data is fed into the DSP which performs the decoding , then the decoded samples have to be converted back into the analog domain , and the resulting signal fed an amplifier or similar audio equipment . This digital to analog conversion (DCA) is performed by a circuit with the same name & Different DCAs provide different performance and quality , as measured by THD (Total harmonic distortion ), number of bits, linearity , speed, filter characteristics and other things. The TMS320 family DQP of Texas Instruments The TLS320family consists of fixed-point, floating-point, multiprocessor digital signal processors (DPs) , and foxed-point DSP controllers. TMS320 DSP have an architecture designed specifically for real-time signal processing . The F/C240 is a number of theC2000DSP platform , and is optimized for control applications. TheC24x series of DSP controllers combines this real-time processing capability with controller peripherals to create an ideal solution for control system applications. The following characteristics make the TMS320 family the right choice for a wide range of processing applications: - Very flexible instruction set - Inherent operational flexibility -High-speed performance -Innovative parallel architecture -Cost effectiveness Devices within a generation of the TMS320 family have the same CPU structure but different on-chip memory and peripheral configurations. Spin-off devices use new combinations of On-chip memory and peripherals to satisfy a wide range of needs in the worldwide electronics market. By integrating memory and peripherals onto a single chip , TMS320 devices reduce system costs and save circuit board space. The 16-bit ,fixed-point DSP core of the C24x devices provides analog designers a digital solution that does not sacrifice the precision and performance of their system performance can be enhanced through the use of advanced control algorithms for techniques such as adaptive control , Kalman filtering , and state control. The C24x DSP controller offer reliability and programmability . Analog control systems, on the other hand ,are hardwired solutions and can experience performance degradation due to aging , component tolerance, and drift. The high-speed central processing unit (CPU) allows the digital designer to process algorithms in real time rather than approximate results with look-up tables. The instruction set of these DSP controllers, which incorporates both signal processing instructions and general-purpose control functions, coupled with the extensive development time and provides the same ease of use as traditional 8-and 16-bit microcontrollers. The instruction set also allows you to retain your software investment when moving from other general-purposeC2xx generation ,source code compatible with theC2x generation , and upwardly source code compatible with the C5x generation of DSPs from Texas Instruments. The C24x architecture is also well-suited for processing control signals. It uses a 16-bit word length along with 32-bit registers for storing intermediate results, and has two hardware shifters available to scale numbers independently of the CPU . This combination minimizes quantization and truncation errors, and increases p2ocessing power for additional functions. Such functions might include a notch filter that could cancel mechanical resonances in a system or an estimation technique that could eliminate state sensors in a system. The C24xDSP controllers take advantage of an set of peripheral functions that allow Texas Instruments to quickly configure various series members for different price/ performance points or for application optimization. This library of both digital and mixed-signal peripherals includes: -Timers -Serial communications ports (SCI,SPI) -Analog-to-digital converters(ADC) -Event manager -System protection, such as low-voltage and watchdog timer The DSP controller peripheral library is continually growing and changing to suit the of tomorrows embedded control marketplace. The TMS320F/C240 is the first standard device introduced in the 24x series of DSP controllers. It sets the standard for a single-chip digital motor controller. The 240 can execute 20 MIPS. Almost all instructions are executed in a simple cycle o f 50 ns . This high performance allows real-time execution of very comple8 control algorithms, such as adaptive control and Kalman filters. Very high sampling rates can also be used to minimize loop delays. The 240 has the architectural features necessary for high-speed signal processing and digital control functions, and it has the peripherals needed to provide a single-chip solution for motor control applications. The 240 is manufactured using submicron CMOS technology, achieving a log power dissipation rating . Also included are several power-down modes for further power savings. Some applications that benefit from the advanced processing power of the 240 include: -Industrial motor drives -Power inverters and controllers -Automotive systems, such as electronic power steering , antilock brakes, and climate control -Appliance and HVAC blower/ compressor motor controls -Printers, copiers, and other office products -Tape drives, magnetic optical drives, and other mass storage products -Robotic and CNC milling machines To function as a system manager, a DSP must have robust on-chip I/O and other peripherals. The event manager of the 240 is unlike any other available on a DSP . This application-optimized peripheral unit , coupled with the high performance DSP core, enables the use of advanced control techniques for high-precision and high-efficiency full variable-speed control of all motor types. Include in the event manager are special pulse-width modulation (PWM) generation functions, such as a programmable dead-band function and a space vector PWM state machine for 3-phase motors that provides state-of-the-art maximum efficiency in the switching of power transistors. There independent up down timers, each with its own compare register, support the generation of asymmetric (noncentered) as well as symmetric (centered) PWM waveforms. Open-Loop and Closed-Loop Control Open-loop Control Systems The word automatic implies that there is a certain amount of sophistication in the control system. By automatic, it generally means That the system is usually capable of adapting to a variety of operating conditions and is able to respond to a class of inputs satisfactorily . However , not any type of control system has the automatic feature. Usually , the automatic feature is achieved by feed. g the feedback structure, it is called an open-loop system , which is the simplest and most economical type of control system.inaccuracy lies in the fact that one may not know the exact characteristics of the further ,which has a definite bearing on the indoor temperature. This alco points to an important disadvantage of the performance of an open -loop control system, in that the system is not capable of adapting to variations in environmental conitions or to external disturbances. In the case of the furnace control, perhaps an experienced person can provide control for a certain desired temperature in the house； but id the doors or windows are opened or closed intermittently during the operating period, the final temperature inside the house will not be accurately regulated by the open-loop control. An electric washing machine is another typical example of an open-loop system , because the amount of wash time is entirely determined by the judgment and estimation of the human operator . A true automatic electric washing machine should have the means of checking the cleanliness of the clothes continuously and turn itsedt off when the desired degised of cleanliness is reached. Closed-Loop Control Systems What is missing in the open-loop control system for more accurate and more adaptable control is a link or feedback from the output to the input of the system . In order to obtain more accurate bontrol, the controlled signal c(t) must be fed back and compared with the reference input , and an actuating signal proportional to the difference of the output and the input must be sent through the system to correct the error. A system with one or more feedback pat(s like that just described is called a closed-loop system. human being are probably the most complex and sophisticated feedback control system in existence. A human being may be considered to be a control system with many inputs and outputs, capable of carrying out highly complex operations. To illustrate the human being as a feedback control system , let us consider that the objective is to reach for an object on aperform the task. The eyes serve as a sensing device which feeds back continuously the position of the hand . The distance between the hand and the object is the error , which is eventually brought to zero as the hand reacher the object. This is a typical example of closed-loop control. However , if one is told to reach for the object and then is blindolded, one can only reach toward the object by estimating its exact position. It isAs anther illustrative example of a closed-loop control system, shows the block diagram of the rudder control system ofThe basic alements and the bloca diagram of a closed-loop control system are shown in fig. In general , the configuration of a feedback control system may not be constrained to that of fig & . In complex systems there may be multitude of feedback loops and element blocks. 數(shù)控 在先進制造技術(shù)領域最根本的觀念之一是數(shù)控（ NC）。數(shù)控來臨之前，所有機床是手工操作和控制。手動控制機床有許多限制，或許沒有比操作者的技能更突出。用手動控制，產(chǎn)品質(zhì)量直接相關(guān)，并 僅限于操作者的技能。數(shù)控具有重要的意義在于它擺脫手動控制機床。 數(shù)控機床意味著，機器操作和其他手寫機器操作系統(tǒng)的到來。操作機床，數(shù)控技術(shù)員只要寫出機床的指示程序，機床就會自動控制，它必須與一個接口接受和解碼程序指示，作為一個讀者已知的設備。 數(shù)控開發(fā)，克服了人工操作的局限性，并且已經(jīng)完成。數(shù)控機床比手動操作機器更為準確，他們可以使得生產(chǎn)部分更得體，他們更快，從長遠來說他的時間花費成本較低。數(shù)控的開發(fā)推動了制造業(yè)的技術(shù)創(chuàng)新發(fā)展： 1。電火花加工。 2。激光切割。 3。電子束焊接。 數(shù)控機床也比他們更早的機器更為的 靈活。一種數(shù)控機床能自動產(chǎn)生的種類繁多，每個涉及的零件，從經(jīng)濟的角度，將不會被可行的手動控制機床和工藝產(chǎn)品的生產(chǎn)品種所替代。 像許多先進技術(shù)一樣，數(shù)控出生于美國麻省理工學院的實驗室。該數(shù)控概念是在 50年代初由美國空軍提出。在最初階段，數(shù)控機床能夠使直接有效地削減人力。 然而，制作彎曲的零件是一個問題，因為機床要進行編程，進行橫向和縱向的一系列步驟，以產(chǎn)生一個曲線。較短的可以用直線組成，是平滑曲線。它的的每一步驟都必須進行計算。 這個問題導致了 1959年自動編程工具（ APT）語言的發(fā)展，使用類似數(shù)控英文語句來定義幾何零件，描述刀具配置，并制定所需的方案。新的 APT語言的發(fā)展是重大的一步，推動數(shù)控技術(shù)的進一步發(fā)展。原來的數(shù)控系統(tǒng)廣泛使用穿孔紙，后來由磁性塑料帶代替。一個使用穿孔紙的人解釋了該機器的磁帶使用說明?？傊?，所有一切都代表數(shù)控控制的大步發(fā)展。然而，有一些問題，就是數(shù)控在這點上的發(fā)展。 一個主要的問題是該打孔紙帶中的脆弱性。就是在輸入程序指令時紙帶的撕裂，比這個問題更加嚴重的是，在機床制造過程中的連續(xù)性，攜帶的紙帶編程指示必須重新運行。如果生產(chǎn)預先制定的 100份，還需要運行 100個紙帶獨立運行的時間。脆弱 的紙帶根本無法承受這樣的環(huán)境，這樣的無法重復使用。 這導致了一個特殊磁帶的發(fā)展。而通過在磁帶打孔系列的編程指令中的紙帶，其中最重要的是，很難或者不可能改變磁帶上輸入的指令。即使是在一個最微小的調(diào)整方案，也需要中斷才能加工，并制作出新的磁帶。它仍然需要盡可能多的時間運行磁帶來實現(xiàn)要產(chǎn)生部分。幸運的是，計算機技術(shù)成為了現(xiàn)實，并很快解決了數(shù)控問題，這與打孔紙和膠帶密切相關(guān)。 作為知名的數(shù)控概念發(fā)展（ DNC）解決了紙張和塑料帶與數(shù)控相關(guān)作為執(zhí)行指令的編程語言磁帶的問題。在直接數(shù)字控制下，精密機床的束縛，通過數(shù)據(jù)傳輸 鏈路，連接在主機和機器工具，通過數(shù)據(jù)傳輸連接需要。直接數(shù)字控制穿孔紙帶和塑料帶的應用上是一個重大的進步。但是，它受所有技術(shù)，在主機上卻有相同的限制。當主機出現(xiàn)故障，機器工具也會出現(xiàn)故障。這個問題引導了計算機數(shù)控的發(fā)展。 關(guān)于可編程邏輯控制器（ PLC）和微型計算機的發(fā)展使微處理器的發(fā)展。這兩項技術(shù)的發(fā)展，計算機數(shù)字控制（ CNC）允許的數(shù)控系統(tǒng)。每臺機器工具， PLC或微型計算機，它為同樣的目的。這允許程序自動輸入和存儲在每個機床上。數(shù)控解決相關(guān)的主機停機的問題，但它推出了著名的數(shù)據(jù)管理的另一個問題。同樣的程序可 能會被裝上 10種不同的微型電腦，它們之間沒有溝通。此問題處理是在當?shù)貐^(qū)域網(wǎng)絡的過程中解決的connectDigital信號處理器的。 在許多情況下的模擬信號會用各種方法處理問題，在很多方面像濾波和頻譜分析，設計模擬硬件來執(zhí)行這些職能是可能的，但已變得越來越少，由于更高的性能需求，靈活性的需求，以及需要削減減少開發(fā) /測試的時間的需求。正是在困難時，換句話說，是模擬信號的硬件設計分析改變了現(xiàn)狀。 抽樣一個信號是專門為嵌入式信號處理的操作，這種處理器被稱為數(shù)字信號處理器，是數(shù)字信號處理器的代表。今天有數(shù)百個家庭的 DSP從盡可能多的制造商，每一個特定的價格 /性能 /使用組來設計的。大的廠家很多，像德州儀器，摩托羅拉，都提供專門的 DSP像馬達控制或調(diào)制解調(diào)器這些領域的，和一般的高性能 DSP處理，可以執(zhí)行廣泛的任務范圍。軟件開發(fā)工具包也可以，也有公司做好 DSP的，允許程序員可以實現(xiàn)復雜的處理算法，利用簡單的 “ 拖放 和 下降 ” 的方法的軟件開發(fā)工具。 DSP的或多或少取決于兩類下降的基礎架構(gòu)的定點和浮點。定點設備操作一般在 16位，而浮點器件上 32-40位浮點操作。不用說，定點設備一般比較便宜。另一個重要的結(jié)構(gòu)不同的地方是，定點 處理器往往只有一個 “ 通用的蓄電池架構(gòu) ” ，這使得他們的方案很棘手，更重要的是，制造的 C-編譯器固有的低效率。浮點 DSP的表現(xiàn)更像是共同的通用 CPU的寄存器文件。 在市場上有成千上萬不同的數(shù)字信號處理器，找到項目最合適的數(shù)字信號處理器是一個艱巨的任務。最好的辦法可能是成立一個約束和心愿，并試圖針對它的最大制造商的處理器來進行比較。 “ 四大 ” 的數(shù)字信號處理器制造商：德州儀器，摩托羅拉， AT T和模擬設備。 數(shù)字至模擬轉(zhuǎn)換 MPEG音頻解碼，數(shù)字壓縮的數(shù)據(jù)反饋到執(zhí)行的 DSP解碼，解碼后的樣本，將轉(zhuǎn)換成模擬域回來 ，與由此產(chǎn)生的信號放大器或類似的音頻設備。這個數(shù)字到模擬轉(zhuǎn)換（ DCA）的工作由一個具有相同名稱和不同音頻媒體的電路提供不同的性能和質(zhì)量，如 THD（總諧波失真），對位，線性度，速度，過濾特征和其他一些。 TMS320系列 DQP的德州儀器 該 TLS320family儀器由定點，浮點組成，數(shù)字信號處理器的多處理器（ DSP）及 foxed點 DSP控制器。 TMS320系列數(shù)字信號處理器設計了實時信號處理具體的架構(gòu)。 F/C240是C2000DSP平臺，并控制應用而優(yōu)化。 C24x的 DSP控制器系列，結(jié)合這個控制器外設的實時處理能力，以創(chuàng)造一個控制系統(tǒng)應用的理想解決方案。以下特點使 TMS320系列正確選擇應用廣泛的加工范圍： -非常靈活的指令集 -固有業(yè)務靈活性