機(jī)械專業(yè)畢業(yè)設(shè)計(jì)外語翻譯

1、<p>　　本科畢業(yè)設(shè)計(jì)（論文）</p><p><b>　　外文譯文</b></p><p>　　院 （系）： 機(jī)電工程學(xué)院 </p><p>　　專 業(yè)： 機(jī)械設(shè)計(jì)制造及其自動化 </p><p>　　姓 名： </p>

2、;<p>　　學(xué) 號： </p><p>　指導(dǎo)教師評語：簽名： 年 月 日</p><p><b>　　外語文獻(xiàn)翻譯</b></p><p><b>　　原文：</b></p><p>　　3.4.1CAD

3、 HARDWARE</p><p><b>　　Computers</b></p><p>　　There are two major types of hardware used in a CAD system. Computer and input/output (I/O) devices. In the early days of CAD. Some comme

4、rcial CAD systems used proprietary computers. Today, nearly all CAD software runs on a general-purpose computer.</p><p>　　Depending on the complexity of the CAD package, it may require a mainframe computer,

5、a minicomputer, or simply a microcomputer. In general, the more functionalities a CAD system provides, the more powerful the computer needed. Three dimensional solid modelers require much more computing than do two-dimen

6、sional drafting systems; thus, they need more powerful computers. Systems that integrate engineering analysis or simulation packages generally are more computation-intensive. A powerful computer </p><p>　　Se

7、veral other parameters and components concerning the computer also have to be considered.</p><p>　　CAD HARDWARE</p><p>　　random-access memory (RAM)capacity</p><p>　　permanent disk-s

8、torage capacity</p><p>　　special graphics accelerator</p><p>　　tape backups</p><p>　　RAM is the actual physical memory (vs. virtual memory)of a computer. A small memory capacity mea

9、ns slow processing due to frequent swapping between the physical memory and the virtual memory on disk. Because CAD is extremely storage demanding, disk capacity is important. Small disk capacity limits the system to the

10、 storage of only a few drawings. CAD is graphics-based and requires tremendous data processing. A graphics accelerator can drastically increase the performance of the system. Another c</p><p>　　Currently, al

11、l levels of computers are used in CAD systems. Personal computers are used in low-cost,2-D drafting applications, and with the new power of these computers, hey are also being used for some 3-D solid modeling application

12、s. Engineering workstations have been the mainstay in CAD, and are usually a single-user CAD workstation in a network. Minicomputers are used in multiuser CAD systems. Mainframes are used for large multiuser CAD system

13、s to support real time simulation and engineeri</p><p>　　3.4.2 Input. Output (I/O)Devices</p><p>　　Figure 3.7 shows the typical I/O devices used in a CAD system. Input devices are generally used

14、 to transfer information from a human or storage medium to a computer where ”CAD functions” are carried out. A keyboard is the standard input device used to transmit alphanumeric data to the system. Function keypads are

15、also used to make input easier. Joysticks, track balls, and mousse are also used to manipulate a cursor. They can be used to position the graphic cursor(e.g. cross hair)on a monitor and</p><p>　　There are th

16、ree basic approaches to input an existing drawing;(1)model the object on a drawing,(2)digitize the drawing, or (3)scan the object. Digitizing is usually much easier than modeling. A digitizer is a device that translates

17、the X-Y locations on a drawing than modeling. A digitizer is a device that translates the X-Y locations on a drawing into a digital and feeds that signal to a computer. Graphics scanners scan a drawing and convert it to

18、a CAD-system-readable format. Some scanners have</p><p>　　The standard output device for CAD is a monitor display. Modern monitor displays are raster-scan display monitors. Similar to a TV monitor, an electr

19、on gun(Sony Trinitron uses three guns for three basic colors)sends an electronic beam to the front of the monitor. Easy display dot is called a pixel(picture element).For color displays, each pixel is represented by thr

20、ee closely located dots with red, green , and blue colors. The electronic beam selects the color elements and the intensity of each</p><p>　　The computer does not draw directly on the monitor. Connecting the

21、 computer to the monitor is u-sually a RGB(red, green, blue)cable. Three separate signal lines are connected. On the graphics board in the computer are circuits to generate the analog signals required to drive the monito

22、r. There is also a frame buffer that serves as memory to store the image. Each pixel on the screen has a corresponding address in the frame buffer. The data in the frame buffer are converted into the appropriate an</p

23、><p>　　The calculator lend support toes to paint the software AutoCAD to make us can be with the sketch that the astonishing speed draw the engineering sketch or machine sketch and other with accuracy to sophis

24、ticate. The calculator paints to paint the different place, one of them with handicraft the paintings with out the diagram divide a step proceed of, because of but would sometimes appear the traditional handicraft the pa

25、inting hour the problem of the impossible emergence. General circumstance bot</p><p>　　ually paint or outsing diagram to have no to need to change to measure to AutoCAD system worth make the modification wit

26、h establish, take its the province worth can normal work, but have the special request, must modify the related system to change measure; Too sometimes the request of the diagram paper with make the diagram's way of

27、doing the antinomy, and be to adopt the to make the diagram method to can't attain the request of the diagram paper, will adopt some techniqueiques to modify the re</p><p>　　AutoCAD line type establishin

28、g of comparison At teaching of process inside would usually run into what this kind of circumstance, while establishing diagram layer, clearly established the point lin eationed, and consequently output to however invest

29、igate its reason for the solid lined, and is usually because of the line typed the establishing of comparison is not appropriate and cau-</p><p>　　sable. Should you so establish the comparison of what kind o

30、f line type? How to use the line type the comparison in the painting?</p><p>　　Usage AutoCAD painting, besides continuous line type( Continuous), the other line type is all from the solid line segment, blank

31、 segment, point series for or text this constituting. On-line type definition document the inside have already defined these line types the segment's standard length, and show on held the act or at print the machine\

32、 painting output, each length and ex-</p><p>　　portation comparison with line type comparison direct proportion. When show or print, the painting boundary that customer that request, this hour establish is o

33、ut of accordance with the painting boundary of the province difference big, on held the act show or paint output's line type would match the engineering graphics to will pass the changes line type comparison the syst

34、em the method that change the deal, enlarge or contract all line types each a small segment of length, make the sketch made </p><p>　　orth all for 1.</p><p>　　For use the line type that Auto CAD

35、2002 painting, big part contain three kinds of forms,( such as: Comparison that Center, Center2, Center*2, Dashed, Dashed2, Dashed*2) the first is a half, the third line type for the standard form, the second line type t

36、hat comparison that the first line type is the first line type of two times, if line type the comparison establish to is not suitable for, and would then make some exportation diagrams the line( such as the point lineati

37、on, dotted line...etc.) c</p><p>　　Two, line breadth the count of establishPass by what handicraft painting, its painting with outs the diagram is a synchronous proceeding of, now calculator painting, its pa

38、inting with outs the diagram divide a step proceeds. Wether draw the construction engineering diagram or machine spare parts diagram, at print control that a work that exportation engineering drawing, the most is a line

39、to print the drawing the breadth, line the type, color, seal a line breadth for, and eachly growing to line </p><p>　　Because of the model of breadth line the space is different from diagram manifestation of

40、 space paper result, in the model space therefore the elephant vegetable show, but in the diagram paper the space is then then to print the width to proceed to show, because of but we while drawing ske tch should know at

41、 the diagram line that true width established by line breadth of model space, and is not equal with object. When the line breadth is worth to establish to"0", it show with the minimum width( </p><p&g

42、t;　　Three, the sketch output the establishing of comparison When we draw sketch that comparison that comparison output the sketch with us hour use different, can make originally text in the sketch that draw word exportat

43、ion comparison for marking noting waiting in the output's sketch take placing changing, therefore at drawing the sketch before returning the beard make suring the sketch.For guaranteeing the sketch to output our want

44、 the literalness size, should when the text word establish usage fol</p><p>　　draw the width of the diagram line to also should consider this point, its to settle the width same as output the width to multip

45、ly by with its comparison worth.</p><p>　　From above practice with analyze to can see out, calculator painting and incompletelyresemble handicraft painting so synchronously paint with out diagram, therefore

46、sometimes make with the diagram method can't attain the request of the diagram paper. Some in common use system that this demand we are deep into control the calculator to paint the theories, and can expertly control

47、 the operation method to change the deal with establish the technique, and can make the work of our painting more conve</p><p><b>　　譯文：</b></p><p>　　3.4.1CAD硬件</p><p>&l

48、t;b>　　計(jì)算機(jī)</b></p><p>　　兩大主要類型的硬件使用于CAD系統(tǒng)，計(jì)算機(jī)和輸入/輸出設(shè)備。在CAD的早期，一些商業(yè)的CAD系統(tǒng)使用于專業(yè)計(jì)算機(jī)。如今，幾乎全部的CAD軟件都運(yùn)用于普通用途的計(jì)算機(jī)。</p><p>　　根據(jù)CAD命令的復(fù)雜性，它可能需要一臺大型計(jì)算機(jī)，一臺迷你型計(jì)算機(jī)，或僅一臺微型計(jì)算機(jī)，大體上，CAD系統(tǒng)提供更好的功能性，需要更有強(qiáng)的計(jì)

49、算機(jī)。三維空間建模比二維線型建模需要更好的計(jì)算機(jī)；因而，他們需要更有力的計(jì)算機(jī)。那使成整體分析的系統(tǒng)或一般模擬命令是更多更強(qiáng)的計(jì)算。一臺強(qiáng)的計(jì)算機(jī)不僅加速CAD系統(tǒng)的運(yùn)行，而且也能支持多個使用者，并不降低使用性能。</p><p>　　幾個其他的參數(shù)和關(guān)于計(jì)算機(jī)的成分，也不得不被考慮。 </p><p><b>　　隨機(jī)存取儲藏器容量</b></p>&

50、lt;p><b>　　磁帶容量</b></p><p><b>　　專用圖形加速器</b></p><p><b>　　磁帶裝置</b></p><p>　　隨機(jī)存取儲藏器容量是計(jì)算機(jī)的實(shí)際的物理內(nèi)存（相對，虛擬內(nèi)存）。小的存取容量導(dǎo)致減慢是由于磁盤上的物理內(nèi)存和實(shí)際內(nèi)存的頻繁交換。因?yàn)椋珻AD

51、是要求非常大非常多的，磁盤容量是重要的。對只有一些圖畫的儲藏小磁盤片能力極限系統(tǒng)， CAD是以圖形為基礎(chǔ)的并且需要巨大的數(shù)據(jù)處理，一個圖形加速器能大幅增加系統(tǒng)的表現(xiàn)。另外的一個成份 ， 硬盤, 典型地是計(jì)算機(jī)系統(tǒng)的主要費(fèi)用。 因此,它不可置疑的儲藏所有線形圖形到硬盤上。 磁帶仍然是為脫機(jī)的數(shù)據(jù)儲藏使用的最節(jié)儉的媒體。有一卷音帶后緩子系統(tǒng)對CAD系統(tǒng)是必需的。</p><p>　　現(xiàn)在，所有水平的計(jì)算機(jī)在CAD系統(tǒng)

52、中被用。 個人計(jì)算機(jī)被用在廉價的,二維的起草申請中 , 和由于這些計(jì)算機(jī)的新力量 , 他們也被用作在一些三維建模申請。 工程工作站在CAD中有主要的依靠, 和通常在一個網(wǎng)絡(luò)中是一個單一使用者CAD工作站.迷你計(jì)算機(jī)在數(shù)字CAD系統(tǒng)中被用。主機(jī)作為大的數(shù)字CAD系統(tǒng)是支援仿真模擬和分析。有時，在大的公司中，所有水平的CAD系統(tǒng)被實(shí)現(xiàn)。 所有的這些系統(tǒng)通過局域網(wǎng)絡(luò)被一起連接。</p><p>　　3.4.2 輸入/

53、輸出 (輸入／輸出) 裝置</p><p>　　圖 3.7 表演在一個CAD系統(tǒng)中被用的典型輸入／輸出裝置。 輸入裝置通常用來轉(zhuǎn)移來自人或儲藏媒體的數(shù)據(jù)到一部計(jì)算機(jī) "CAD功能" 在哪里實(shí)行。 一個鍵盤是標(biāo)準(zhǔn)的輸入裝置，過去一直送字母與數(shù)字并用的數(shù)據(jù)到系統(tǒng)。 功能按鍵區(qū)也使輸入更容易。 游戲操縱桿,追蹤球，而且鼠標(biāo)也用來操作光標(biāo)。 他們能用來放置一個監(jiān)視器上的繪畫似的光標(biāo) ( 舉例來說十字架

54、頭發(fā)) ，而且回饋對計(jì)算機(jī)在監(jiān)視器上的目標(biāo)位置。使用這些裝置允許一個操作員交談式在到達(dá)一個正確的位置方面向終端指出位置。操縱桿和追蹤球在CAD系統(tǒng)中不被廣泛運(yùn)用，由于很難的找到正確的位置。鼠標(biāo)被廣泛地用于窗口和下拉式菜單，他們?yōu)橹赋鍪侨菀资褂玫?然而, 使用一只鼠標(biāo)跟蹤曲線不是一件容易的工作。</p><p>　　有三個基本接近到輸入一幅已存在的圖畫;(1)一幅圖畫上的物體模型 , 數(shù)字化圖畫 , 或 (3) 掃

55、描物體。 數(shù)字化通常比模型容易。一個數(shù)字化是進(jìn)入數(shù)傳信號之內(nèi)在一幅圖畫上翻譯 X- Y 軸位置的裝置和對一部計(jì)算機(jī)的追蹤信號。 圖形掃描機(jī)掃描一幅圖畫而且將它轉(zhuǎn)換成CAD系統(tǒng)可讀格式。 一些掃描機(jī)有內(nèi)建的字符識別軟件進(jìn)入美國信息交換標(biāo)準(zhǔn)代碼密碼之內(nèi)在紙上轉(zhuǎn)換字符。 另外的一個輸入裝置是一本手抄簿叫做圖形平板。 一個圖形平板是一個使用者用鐵筆拉出的特別的平面。鐵筆的位置被派遣去計(jì)算機(jī)。板是一個 同等的裝置。 實(shí)現(xiàn)平板上的疊菜單而且實(shí)現(xiàn)熒屏

56、上的下拉式菜單改良操作是容易的。 現(xiàn)在，平板是在鍵盤之外的CAD系統(tǒng)中流行的輸入裝置</p><p>　　標(biāo)準(zhǔn)的輸出裝置對CAD監(jiān)視器顯示?，F(xiàn)代監(jiān)視器是試映圖- 掃描炫耀監(jiān)視器類似一個電視監(jiān)視器，一個電子槍 (Sony 單槍三束彩色映像管使用三只槍作為三基本顏色)送電子的光線給監(jiān)視器的前面。 每一個炫耀點(diǎn)叫做一個像素 (照片元素) 為彩色顯示，每個像素三點(diǎn)之間被接近地表現(xiàn)為紅色的，綠色的，和藍(lán)色的顏色。電子的光線

57、選擇彩色元素和每種彩色元素的強(qiáng)度。監(jiān)視器的分辨率被熒屏上炫耀像素的數(shù)量所決定。（像素640*480，1024*1024）</p><p>　　和像素點(diǎn)大?。?4位，32位，等等）。色相和灰度的決議通過不同的色相或灰色刻度決定或開或關(guān)。一個灰色刻度至少2點(diǎn)允許三種強(qiáng)度光加號遠(yuǎn)的（2*2）。通常，閃光是4點(diǎn)（16位色），8點(diǎn)（256位色），16點(diǎn)（數(shù)千位色），和24點(diǎn)（數(shù)百萬色）。電子的光線從頂端到線的底線掃除熒屏。

58、因?yàn)楸粸橹挥姓嬲亩虝r段點(diǎn)亮, 掃除一定被非常快地依照順序做不要有一閃爍圖像。使比率尺寸是監(jiān)視器在一秒內(nèi)閃爍多少次來衡量。</p><p>　　計(jì)算機(jī)不直接的依賴監(jiān)視器。通常連接計(jì)算機(jī)到監(jiān)視器是 RGB(紅色的，綠色的,藍(lán)色的) 電纜。 三分開信號線被連接。 在計(jì)算機(jī)中的圖形是產(chǎn)生類比信號的線路。 也有一個視為記憶儲存圖像的緩沖。 熒屏上的每個像素在構(gòu)成緩沖中有一個相應(yīng)地址。 數(shù)據(jù)在構(gòu)成緩沖中被轉(zhuǎn)換成適當(dāng)?shù)念惐刃?/p>

59、號并且送給監(jiān)視器在那使比率。分開的，計(jì)算機(jī)直接的寫到構(gòu)成緩沖它想要拉出的像像。顏色的閃耀大小和數(shù)字愈比較很棒, 構(gòu)成緩沖是需要的也愈較多。 圖形上的構(gòu)成緩沖是隨機(jī)存取儲藏器（隨機(jī)存取儲藏器）</p><p>　　AutoCAD的系統(tǒng)變量</p><p>　　計(jì)算機(jī)輔助繪圖軟件AutoCAD使我們能以驚人的速度和精度繪制工程圖形或機(jī)械圖形以及其它復(fù)雜的圖形。計(jì)算機(jī)繪圖與手工繪圖不同之處，其中

60、之一是繪圖與出圖是分步進(jìn)行的，因而有時會出現(xiàn)傳統(tǒng)手工繪圖時不可能出現(xiàn)的問題。一般情況下，使用AutoCAD進(jìn)行繪圖，掌握精確繪圖并不太難，而要準(zhǔn)確出圖則需要一定的技巧。通常繪圖或出圖無需對AutoCAD系統(tǒng)變量值作修改和設(shè)置，取其缺省值就能正常工作，但有特殊要求時，就必須修改相關(guān)的系統(tǒng)變量；也有的時候圖紙的要求與作圖的直觀做法相矛盾，當(dāng)采取直觀作圖法無法達(dá)到圖紙的要求時，就要采用一些技巧來修改相關(guān)的系統(tǒng)變量，才能使計(jì)算機(jī)繪出和輸出的圖形

61、達(dá)到圖紙的要求。2.1AutoCAD 線型比例的設(shè)置 在教學(xué)的過程中常常會碰到這種情況，在設(shè)置圖層時，明明設(shè)置了點(diǎn)劃線，結(jié)果輸出卻為實(shí)線，究其原因，往往是由于線型比例的設(shè)置不恰當(dāng)引起的。那么應(yīng)該設(shè)置什么樣的線型比例？如何在繪圖中使用線型比例？    使用AutoCAD繪圖，除連續(xù)線型外，其它線型均由實(shí)線段、空白段、點(diǎn)或文本所構(gòu)成的系列。在線型定義文件中已定義了這些線型段的標(biāo)準(zhǔn)長度，在屏

62、幕上顯示或在打印機(jī)\繪圖儀</p><p>　　2.2線寬參數(shù)的設(shè)置    過去手工繪圖，其繪圖和出圖是同步進(jìn)行的，如今計(jì)算機(jī)繪圖，其繪圖和出圖是分步進(jìn)行的。無論是繪制建筑工程圖還是機(jī)械零件圖，在打印輸出工程圖樣時，最主要的一項(xiàng)工作是控制打印圖樣的線寬、線型、顏色、封口，且每種線型都有其相應(yīng)的線寬，在舊版本的AutoCAD繪圖過程中，即使定義了線型寬度，其在視圖區(qū)也不能顯

63、示出線型寬度的區(qū)別（不含多義線）。只能通過圖層或設(shè)定線的顏色來區(qū)分線的寬度。目前繪圖員考證的試題，采用的就是這種方法。而在AutoCAD2002中，新增了”Lweight”（線型寬度設(shè)置）命令，為用戶提供了新的功能，即利用實(shí)體特性進(jìn)行控制，為圖形的實(shí)體設(shè)置線寬，利用它可以在屏幕上顯示和打印輸出時，控制實(shí)體的線寬。2002版中打印設(shè)置可分為三個部分，分別為打印機(jī)屬性設(shè)置、打印樣式設(shè)置及頁面設(shè)置。   

64、60;由于線寬的模型空間和圖紙空間的顯示效果不同，在模型空間是以象素顯示，而在圖紙空間則是以打印寬度進(jìn)行顯示，因而我們在繪制圖形時應(yīng)認(rèn)識到在模型空間由線寬設(shè)置的圖線，與對象的真實(shí)寬度并不相等。當(dāng)線寬值設(shè)為“0”時，它在屏幕上以最小的寬度（一個象素寬）顯示，線寬定為其它值時</p><p>　　同理，繪制圖線的寬度也應(yīng)該考慮這點(diǎn)，其給定寬度等于輸出寬度乘以其比例值。