六足爬蟲機器人機械結(jié)構(gòu)設(shè)計-含動畫仿真【JS系列】,JS系列,爬蟲,機器人,機械,結(jié)構(gòu)設(shè)計,動畫,仿真,js,系列 Computer and Design The computer has had a major impact on the way everyday tasks associated with design are accomplished .It can be used in many ways to do many things. However, all design tasks accomplished using a computer fall into one of four broad categories: *design modeling *design analysis *design documentation 1. Design Modeling In CAD/CAM design modeling, a geometric model of a product is developed that describes the part mathematically. This mathematical description is converted to graphic form and displayed on a cathode ray tube (CRT). The geometric model also allows the graphic image to be easily edited and manipulated once displayed. The process begins when a designer creates a graphic image using a special ICG software package. The image is created by entering commands that cause the computer to construct the image out of points, lines, circles, and curves. To create a graphic image, the computer must translate the geometric characters into a corresponding mathematical model. What appears to the designer as a graphic image is stored in the computer as a series of mathematical coordinates. As the designer issues commands to edit or manipulate a graphic image, the computer revises the mathematical model .The computer must first change the geometric model before it can change the graphic image, and it must calculate the mathematical coordinates of a geometric character before it can display that character. Graphic images are displayed in one of three formats: ．two-dimensional or 2-D ．two-and-a-half-dimensional or 21/2-D ．three-dimensional or 3-D These three formats are illustrated in Fig.2.3 , 2.4 and 2.5 .A2-D graphic image shows an orthographic(flat) representation and usually shows two or more views (e.g. ,top ,front ,and right side).A 21/2-D graphic image is an oblique representation . A 3-D graphic image may be a wireframe model or a true 3-D solid model (Fig2.6). Communication can be enhanced further when graphic images are displayed in color .Many capabilities of CAD/CAM, including finite-element analysis, wireframe 3-D, and solids modeling , are more easily understood when the graphic images are Fig 1 displayed in color .Specific applications such as piping drawings are also easier to read when displayed in an appropriate variety of colors . When graphic images are displayed in only one color ,it is sometimes difficult to determine when lines cross over or under ,what is near and what is far away ,what is the original image and what is the distorted image (as in the case of finite-element analysis), and which layer a given component is on .The use of color allows for a more definitive distinction between over and under ,near and far ,and original and distorted .It also helps clarify objects consisting of numerous surfaces or several component parts . 2. Design Analysis The computer has simplified the design analysis stage of the design process significantly .Once a proposed design has been developed, it is necessary to analyze how it will stand up to the conditions to which it will be subjected .Such analysis methods as heat transfer and stress-strain calculations are time-consuming and complex .With CAD/CAM, special computer programs written specifically for analysis purposes are available. Fig 2 One such program that has simplified the analysis of manufactured products is called finite-element analysis .Finite-element analysis involves breaking an object up into many small rectangular or triangular elements (Fig.2.7),then analyzing each individual element by computer .This approach gives a thorough analysis that might not be feasible without the aid of a computer .It also offers the advantage of specifically pinpointing the locations of problems so that design corrections can be more easily made . With finite-element analysis , the computer must have a powerful processing capability .The computer analyzes the whole object by analyzing each individual interconnected finite element .By analyzing the response of each finite element of the object to the stress ,strain ,heat ,or other force acting on it ,the computer can predict the reaction of the whole object . Modern CAD/CAM systems with finite-element analysis capability make the process simple to achieve .Users define the area that is to be divided .The computer then automatically divides the area into the interconnected network of finite elements. Fig 3 A particularly valuable characteristic of finite-element analysis is its ability to visually display the results of the analysis. For example, if a part is to be analyzed to determine how it will behave when subjected to a specified amount of stress, the computer is able superimpose the image of the stressed part over the unstressed part .In this way, the resultant distortion can be easily seen .Such visual evidence of the results can make it easier for the designer to pinpoint the necessary design changes. 3. Design Review Another step in the design process that has been simplified by the computer is design review .This involves checking the accuracy of all aspects of the design .There are several ICG capabilities that make design review in CAD/CAM easier than with manual design . The first is the semiautomatic dimensioning capability of many CAD/CAM software packages .To produce a graphic image, an ICG system must first create a mathematical model .The data in this model can be used by the computer for calculating dimensions automatically .Most good CAD/CAM software packages can display these dimensions according to standard dimensioning and tolerancing practices .This means fewer dimensioning errors, a common problem with manual dimensioning. The layering capability of CAD/CAM software also simplifies design review .If a multisided printed circuit board has been designed, the traces for each successive layer can be displayed simultaneously. In this way, traces can be easily checked to ensure that all connections have been properly laid out. The layering capability can also be used to check complex piping layouts to ensure that pipes do not intersect where they should not and do intersect where they should .Good CAD/CAM systems can operate on over 250 layers. Another CAD/CAM software capability that has simplified design review is called interference checking .With this capability, mating parts can be joined on the CRT display as they would be in a final assembly. The designer can see immediately if there is interference .With interference checks, the computers zoom capability is particularly useful. Zoom allows the designer’s eye to move progressively closer to small, intricate details in a drawing .It gives the appearance of magnified small details so they can be seen more easily. This is particularly useful when working on complex assemblies made up of numerous small subassemblies. Some of the more advanced CAD/CAM software packages have a kinematic capability .This means they can simulate motion on a CRT display .This is particularly useful when working on a design made up of moving parts .Computer simulation in such cades takes the place of the cardboard and plastic models used by designers in the past . 4. Design Documentation Design documentation is another area in which CAD/CAM offers major benefits when compared with manual drafting techniques .With CAD/CAM, the drawings needed to document the design can be produced using the database created during the design process. Five-fold improvements in drafting productivity are now common with modern CAD/CAM systems. CAD/CAM software has simplified such time-consuming drafting tasks as dimensioning, creating magnified views of intricate details, transformations (e.g., isometric, diametric, and trimetric projections),scaling , correcting errors ,and making design revisions .It also made the concept of non repetition a reality in drafting . One of the most unproductive tasks associated with manual drafting is redrawing details ,sectional views ,of other drawings that have been previously drawn .Because the computer can store the mathematical models of all drawings done on a CAD/CAM system , once drawing has been produced ,it never has to be redrawn .It can simply be called up from storage ,entered into the appropriate location in the drawing package ,and used again and again . 計算機與設(shè)計 在日常工作與設(shè)計中計算機產(chǎn)生了重大影響，發(fā)揮很大的作用。他被應(yīng)用在很多領(lǐng)域，做很多事情。然而，使用計算機所有完成的設(shè)計工作分為四大類： *設(shè)計建模 *設(shè)計分析 *設(shè)計文件 1 .設(shè)計模型 在CAD / CAM設(shè)計建模，幾何模型產(chǎn)品的開發(fā)，描述了部分?jǐn)?shù)學(xué)。在陰極射線管（ CRT ）中這種數(shù)學(xué)描述轉(zhuǎn)換為圖形的形式被顯示出來。幾何模型還允許一次性展示圖像，這樣可以方便地編輯和操縱。 該過程開始時，設(shè)計者采用特殊的全球?qū)Ш叫l(wèi)星系統(tǒng)軟件包創(chuàng)建了一個圖形圖像。圖像由輸入命令使計算機的形象建設(shè)成點，線，圈和曲線。要創(chuàng)建一個圖形圖像，計算機必須翻譯成與幾何特征相應(yīng)的數(shù)學(xué)模型?？磥碓O(shè)計師在計算機中 作為一個圖形圖像存儲一系列數(shù)學(xué)坐標(biāo)。用設(shè)計師的命令修改或操縱的圖形圖像，用計算機去修改數(shù)學(xué)模型。計算機必須首先改變幾何模型，然后才可以改變圖像，它必須根據(jù)相應(yīng)的數(shù)學(xué)坐標(biāo)的幾何特征，然后才可以顯示字符。 圖像顯示有三種格式： 。兩維或二維 。兩維半立體或21/2-D 。立體或三維 這三種格式的說明圖分別為2.3,2.4和2.5 。素A2的三維圖像顯示字形（單位）通常顯示兩個或兩個以上的部位（例如，頂部，前面和右側(cè)） 。甲21/2- D圖像是一個斜的代表性圖形。三維圖形圖像可能是一個線框模型或一個真正的三維實體模型（ 圖2.6 ） 。 通訊可以進一步提高時，圖像的顏色會顯示出來。許多功能的CAD /CAM ，包括有限元分析，線框3 - D和固體建模，更容易使圖形圖像顏色顯示出來。具體應(yīng)用如管道圖紙顯示適當(dāng)?shù)母鞣N顏色更易于閱讀顯示。當(dāng)圖像都顯示在只有一種色彩時，在層某一部分上有時難以確定何時線交叉或依據(jù)是什么，什么是附近不遠的地方，什么是原始圖像和什么是扭曲的圖像（如有限元分析） 。使用顏色可以更明確的區(qū)分，并有根據(jù)可尋。它還有助于澄清許多組成的物體表面或幾個組成部分近及遠，和原來的和歪曲的。 2 .設(shè)計分析 計算機簡化了設(shè)計分析階段的設(shè)計過程。一旦提議設(shè)計已制定，它將會對如何使用的這些條件作出必要分析，。這種分析方法作為傳熱和壓力應(yīng)變計算耗時等復(fù)雜的依據(jù)。與CAD / CAM系統(tǒng)，特殊的計算機程序為分析提供專門目的。這樣的一個程序，簡化了分析制成品被稱為有限元分析。有限元分析的對象涉及打破成許多小矩形或三角形的要素（ 圖2.7 ） ，然后分析每個元素的計算機。這種做法給出了透徹的分析，但援助的一臺計算機，可能是不可行的。它也可以提供其優(yōu)勢，特別是要確定地點，以便可以更容易地取得更正好設(shè)計。與有限元分析相比，計算機必須有一個強大的處理能力。計算機對整個對象進行分析，每個有相互關(guān)聯(lián)的有限元。通過分析響應(yīng)有限元的每個對象的應(yīng)力，應(yīng)變，熱，或其他力上，計算機可以預(yù)測整個對象的反應(yīng)能力?，F(xiàn)代CAD / CAM系統(tǒng)與有限元分析能力相比，使該進程簡單易于實現(xiàn)。用戶對確定的領(lǐng)域進行劃分。計算機自動劃分領(lǐng)域有相互關(guān)聯(lián)的網(wǎng)絡(luò)—有限元。特別寶貴有限元分析的特性使它能夠直觀顯示分析結(jié)果。例如，如果對一個部分進行分析，以確定它如何表現(xiàn)時，將受到特定重量的壓力，電腦能夠疊加的強調(diào)部分的輕聲一部分形象。通過這種方式，由此造成的失真可容易看到。這種視覺證據(jù)的結(jié)果可以更容易地設(shè)計，最終確定必要的設(shè)計更改。 3 .設(shè)計審查 另一個步驟在設(shè)計過程中對計算機的設(shè)計審查已被簡化了。這就需要檢查所有方面的設(shè)計的準(zhǔn)確性。有幾個全球?qū)Ш叫l(wèi)星系統(tǒng)有能力使設(shè)計審查在CAD / CAM容易與手工設(shè)計結(jié)合。 首先是許多CAD / CAM軟件的軟件包半自動標(biāo)注能力。為了產(chǎn)生一個圖像，一個全球?qū)Ш叫l(wèi)星系統(tǒng)的系統(tǒng)必須先建立數(shù)學(xué)模型。在此模型數(shù)據(jù)可用于計算機自動計算層面。根據(jù)標(biāo)準(zhǔn)尺寸及公差多數(shù)良好的CAD / CAM軟件的軟件包可以顯示這些方面的做法。這意味著有更少的標(biāo)注錯誤，與人工標(biāo)注面臨一個共同的問題。 具有分層能力的CAD / CAM軟件還簡化了設(shè)計審查。如果一個多面印刷電路板的設(shè)計，可同時顯示每個的痕跡連續(xù)層。通過這種方式，可以很容易地追蹤檢查，以確保所有的連接已被適當(dāng)?shù)卮_定。分層能力還可以用來檢查管道布局復(fù)雜，良好的CAD / CAM系統(tǒng)可以在超過250層以確保管道不相交，他們不應(yīng)該這樣做，他們應(yīng)該相互交叉。 另一個CAD / CAM軟件功能，所謂干涉檢查簡化了設(shè)計審查。利用這一功能，交配部分可加入的CRT顯示器，因為它們將能夠在最后組裝。變焦可以讓設(shè)計者的眼睛，以逐步接近小、復(fù)雜的細節(jié)來繪圖，設(shè)計師可以立即看到是否有干擾。干擾檢查對計算機變焦能力是特別有用。它的出現(xiàn)能夠放大小細節(jié)，使他們能夠更容易地看到。對復(fù)雜的組件組成的許多小部件時這是特別有用的工作。一些較先進的CAD / CAM軟件套件有運動能力。這是特別有用的工作時，這意味著他們可以模擬運動的CRT顯示器。設(shè)計了移動部件，在過去設(shè)計師使用計算機模擬這種cad取代紙板和塑料模型。 4 .設(shè)計文件 設(shè)計文件為另一個領(lǐng)域的CAD / CAM提供了主要的利益相比性，手冊起草技術(shù)。與CAD / CAM系統(tǒng)相比，在設(shè)計過程中需要的圖紙能利用創(chuàng)建的數(shù)據(jù)庫設(shè)計文件。與現(xiàn)代CAD / CAM系統(tǒng)相比改善了5倍生產(chǎn)力。CAD / CAM軟件簡化這種耗費時間的起草任務(wù)、設(shè)計修改，標(biāo)注，放大錯綜復(fù)雜的細節(jié)，變化（例如長，直徑和半徑預(yù)測） ，縮放，糾正錯誤。其中，最非生產(chǎn)性任務(wù)是人工重新起草細節(jié)，局部的觀點，其他圖紙此前已制定。因為把電腦可以存儲的數(shù)學(xué)模型的所有圖紙上裝進CAD / CAM系統(tǒng)，一旦圖紙已制作，它從來沒有被重新繪制。它可以簡單地被稱為從儲存，在圖紙封裝時進入適當(dāng)?shù)奈恢?，并一次又一次的使用?