外文翻譯--cnc 機器上自由形態(tài)表面非連絡(luò)自動機械測量

1、<p>　　畢業(yè)設(shè)計(論文)外文資料翻譯</p><p>　　系　　部： 機械工程系 </p><p>　　專 業(yè)： 機械工程及自動化 </p><p>　　姓 名： </p><p>

2、　　學(xué) 號： </p><p>　　外文出處：Non-contact automatic measurement </p><p>　　of free-form surface profiles on CNC machines</p><p>　　附

3、 件： 1.外文資料翻譯譯文；2.外文原文。 </p><p>　　附件1：外文資料翻譯譯文</p><p>　　CNC 機器上自由形態(tài)表面非連絡(luò)自動機械測量</p><p><b>　　摘要</b></p><p>　　這論文描述在CNC機床或坐標(biāo)測量機（CMM）和它的CAD/CAM綜合為任何的自由形態(tài)的表面發(fā)展一個

4、非連絡(luò)類型自動機械測量系統(tǒng)的工作。</p><p>　　一個Keyence公司模型LC-2220激光探針,作為非連絡(luò)感應(yīng)器被整合到CNC機器之內(nèi)。已經(jīng)發(fā)展了一個為任何自由形態(tài)輪廓的自動表面追蹤的測量軟件。對于反向工程任何的市售 CAD/CAM系統(tǒng)的轉(zhuǎn)換數(shù)據(jù)，通過正確的DXF文件,也是可得的。

5、 </p><p>　　廣泛的校準(zhǔn)工作，在關(guān)于顏色，材料，表面斜坡，和使用HP5528激光干涉儀的工件邊緣偵測方面,激光探測的系統(tǒng)精確方面已經(jīng)實現(xiàn)了。在使用表面描繪技術(shù)后，副本物體的形狀誤差，相對于它的樣品，不超過30微米，對于鑄型業(yè)應(yīng)該是足夠了。</p><p><b>

6、　　1.引言</b></p><p>　　自從1960年，英國的Ferranti公司發(fā)展了第一部坐標(biāo)測量機(CMM)，空間度量衡學(xué)的測定效率，已經(jīng)在工業(yè)中得到很大的改良。照慣例，大部分CMMs裝備有接觸探針，為了在如線，平面，圓，柱面，球，圓錐體，等幾何因數(shù)方面的接觸類型測量。測量的程序在以上因素方面的確非?？於铱芍貜?fù)，因為只需要探測點的少數(shù)數(shù)字，而且探測半徑的補償是相當(dāng)簡單的。然而當(dāng)3D自由形態(tài)表

7、面測量的需要近幾年來增加，尤其隨著反向工程的鑄型業(yè)，當(dāng)在很多測量點方面應(yīng)用接觸探測時，許多缺點被發(fā)現(xiàn)。一些典型的問題是：</p><p>　　由于重復(fù)的進出表面的運動，速度不是夠快。</p><p>　　被抽取樣品的位置因探測速度而影響，</p><p>　　被抽取樣品的點可能不夠適當(dāng)來正確地表現(xiàn)標(biāo)準(zhǔn)的表面，</p><p>　　探頭頂尖的半

8、徑補償更難。</p><p>　　探頭頂尖容易很快磨損，而且一些機械結(jié)構(gòu)和伺服控制器的誤差可能會發(fā)生。</p><p>　　為了改善上述缺點，在過去四年，有些激光探頭已經(jīng)開發(fā)出來，用于自由曲面的非接觸式測量。此外，在應(yīng)用這種探針到CNC型的CMM時，系統(tǒng)的測量精度和速度可以大大提高5-6倍，及CAD / CAM集成可以很容易地實現(xiàn)其逆向工程的目的。</p><p>

9、　　這論文描述使用了一個低成本激光探針到一個DCC（直接的計算機控制）型的CMM來為3D自由形態(tài)表面和基于反響工程的CAD/CAM軟件發(fā)展一個自動的非接觸測量系統(tǒng)。如此的技術(shù)也被適用于 CNC機器中心來建立一個機器測量系統(tǒng)。激光的一個深入口徑測定探查主要是調(diào)查有關(guān)的材料，表面坡度，顏色，以及待測量工件的邊緣檢測 。在使用表面涂層技術(shù)后，再生產(chǎn)的工件形狀誤差相對于它的主件在30jrn之內(nèi)，這個誤差對于模具業(yè)的要求應(yīng)該是足夠的。2激光探針

10、的工作原理</p><p>　　用于此項研究的激光探針是一個帶有LC–2100的KeyenceLC-2220傳感器頭。這種成本低可見的激光探針通過激光三角提供位移測量技術(shù)。正如圖1所示，從半導(dǎo)體發(fā)射器發(fā)出的聚焦的激光束投影到物體表面。由于表面粗糙度，反射光束將分散和通過激光接收鏡頭部分收集。通過這個鏡頭，光束將集中和投影到位置敏感探測器(PSD)的傳感器頭。如果被測量物體移動(Lx,圖中), 反射激光光斑也通過P

11、SD手段移動。然后，這點位移通過這里也被稱為控制器的數(shù)據(jù)處理轉(zhuǎn)換為一個模擬或數(shù)字信號。最后，該控制器進行數(shù)據(jù)處理，如線性補償和平均值計算，顯示和輸出測量結(jié)果。</p><p>　　3 激光探針的性能試驗</p><p>　　所有的非接觸式位移傳感器，如渦流型，超聲波型，氣動型，激光束反映類型，它們的性能曲線都與測試對象的表面性質(zhì)有關(guān)。一些激光探針表面特性的重要參數(shù)，包括材料，顏色，粗糙度，

12、以及物體表面的斜坡。大多數(shù)激光探測器的規(guī)格，然而，業(yè)務(wù)手冊中沒有提供足夠的信息。所列出的反應(yīng)制造商所提供的任何特定的激光探針的性能特點的數(shù)據(jù)通常沒有直接適用于特定的加以衡量的對象。因此，首要的工件方面的激光探針必須被采用以保證測量結(jié)果更準(zhǔn)確。</p><p>　　3.1激光探針標(biāo)定的系統(tǒng)設(shè)置</p><p>　　圖2顯示了激光探針標(biāo)定系統(tǒng)實驗裝置。進行校準(zhǔn)的激光探針是安裝在三坐標(biāo)測量機(C

13、MM, DCC 類型, Numerex 有限公司）。那個測試試樣放在一個正弦把手上。正弦波的角度和高度能被規(guī)區(qū)塊千斤頂分別地調(diào)整。HP5528激光干涉儀用于提供相關(guān)相對于激光探針輸出的丟失。主軸可由計算機逐步移至向上和向下。因此，一旦開始，這個校準(zhǔn)任務(wù)可根據(jù)德國工程師協(xié)會3441標(biāo)準(zhǔn)自動處理。而且每個操作被運行五次雙方向的行進。各種實驗然后改變不同的如材料（鋼，鋁合金，和電木）斜坡（ 0到60度的步驟） ，顏色（原始的，和白色，紅色，黃

14、色著色），和表面粗糙度(0.4pm到3pm)的試樣條件調(diào)查序列。</p><p><b>　　3.2校準(zhǔn)結(jié)果</b></p><p>　　眾多的校準(zhǔn)數(shù)據(jù)是不同的試樣條件方面收集的。圖3A說明了研究電木標(biāo)本方面典型圖位移誤差，其原來的顏色（棕） ，和有激光束的表面。結(jié)果發(fā)現(xiàn)，在測量范圍（±2毫米）的最大位移誤差為-l8pm，但重復(fù)性和扭轉(zhuǎn)錯誤都非常好。圖 3

15、b它的直線性有最少－角尺線彎曲。表1總結(jié)在同樣的條件下五個測試結(jié)果。一個有趣的現(xiàn)象可以看見，表面坡度也增加了位移誤差。它可以解釋說，如圖4所示物體表面上散射光沿鏡面方向執(zhí)行高斯分布。隨著表面正常正在遠離激光束軸，被反映的由感應(yīng)器頭中的光接受透鏡收集光束的強度會降低,這將導(dǎo)致低信號噪聲(S/N)。 因此，線性度會越來越差。然而，幸運的是，重復(fù)性仍然和以前一樣好(在2pm之內(nèi))。</p><p>　　類似的研究也分別

16、在鋁合金樣品鋼樣品執(zhí)行. 此外，激光探針性能的表面顏色的影響通過在被測試的表面上涂不同的顏色來研究.表2總結(jié)了激光探針關(guān)于鋁合金在不同的斜度和不同的表面顏色方面的校準(zhǔn)結(jié)果. 一個重要現(xiàn)象是,無論表面坡度的變化,紅表面總是可以確保激光探針有很好的精度性能。由于鋁合金試樣改為鋼試樣,類似的結(jié)論如表3所示仍然可以得到.從這些研究中，模具制造行業(yè)可以考慮, 當(dāng)利用帶有激光探針逆向工程技術(shù)生產(chǎn)模具, 如果是涂有紅色油漆,可以大大提高主件的測量精度

17、.</p><p>　　在激光探針測量時,工件表面粗糙度的影響已經(jīng)先前調(diào)查了. 結(jié)果發(fā)現(xiàn)，在任何加工表面合理Ra值(0.4to3pm),只要光學(xué)平面激光探頭垂直于表面,校準(zhǔn)結(jié)果并沒有表現(xiàn)出顯著的變化.由于大多數(shù)測量的工件必須擦亮到確定的小的Ra值，這種影響，因此可以忽略不計。 4激光探針邊緣檢測能力的增強</p><p>　　大多數(shù)市場上的

18、激光探針只提供位移測量的功能. 雖然這一功能可以使表面描測量的技術(shù)成為可能,但大多數(shù)激光探針在邊緣檢測方面的能力現(xiàn)在仍然非常差. 一些在這一技術(shù)的解決方案將會發(fā)生, 因為任何幾何形狀的工件必須有邊界。一種這方面的方法在這項工作中被提議.</p><p>　　所調(diào)查的激光探針，帶有LC - 2100控制器傳感器頭的Keyence LC-222,具有數(shù)字化,模擬輸出端口。數(shù)字端口通過RS - 232C接口或GPIB接

19、口為外部設(shè)備傳輸數(shù)字讀數(shù). 同時，類似端口按比例發(fā)送一個電壓值送到儀表閱讀向外到一外部的A/D轉(zhuǎn)換器。隨著激光探頭是在其測量范圍之外,無效的地區(qū),數(shù)字讀出(DRO）會出現(xiàn)一個“黑色”的模擬信號而且類似端口將輸出6.55伏特。隨著激光探針位于其有效的區(qū)域,在對于表面的參考距離, 模擬信號將輸出電壓零。</p><p>　　最初的實驗在CMM上單位工作表面上的參考距離通過設(shè)置激光探針進行的.然后水平地而且重復(fù)地被移動

20、進移動出表面,如圖5所示.模擬信號的電壓變化通過數(shù)字示波器觀察到.圖6顯示了一個典型展示,當(dāng)通過工作表面的銳利的邊緣的電壓變化.清楚地看到,當(dāng)沿銳利邊緣從無效區(qū)域到有效的區(qū)域,輸出信號出現(xiàn)明顯和進給速度成正比的延遲時間.然而，當(dāng)從有效區(qū)域到無效區(qū)域移動探針時,在邊緣地區(qū)輸出信號立即作出反應(yīng).這種現(xiàn)象是很難解釋。然而作者認(rèn)為，這可能是由于激光探針的三角原理。然而，指出了一個可行的解決辦法，該邊緣檢測應(yīng)該從有效的區(qū)域到無效的區(qū)域做到.另一個

21、重要因素還應(yīng)當(dāng)指出是,光學(xué)平面的運動必須垂直于表面位置,否則光將嚴(yán)重分散.</p><p>　　為了驗證激光探針中的邊緣檢測的增強的能力,三維測量在一條線和一個圓分別測量. 圖7A及圖7B顯示每個被提議的測量路徑. 圖8A和圖8B測量結(jié)果都非常符合相應(yīng)的標(biāo)稱尺寸。</p><p><b>　　附件2：外文原文</b></p><p>　　Non

22、-contact automatic measurement of free-form surface profiles on CNC machines</p><p><b>　　ABSTRACT</b></p><p>　　This paper describes the work to develop a non-contact type automatic m

23、easurement system for any free-form surfaces on a CNC machine tool or a coordinate measuring machine (CMM), and its CAD/CAM integration.</p><p>　　A laser probe, made by Keyence Co. model LC-2220, was integra

24、ted into the CNC machine as the non-contact sensor. A measurement software has been developed for automatic surface tracing of any free-form profile. Data transfer to any commercially available CAD/CAM system for reverse

25、 engineering is also available via proper DXF file.</p><p>　　Extensive calibration work has been carried out on the systematic accuracy of the laser probe with respect to the color, material, surface slope,

26、and edge detection of the workpiece by the use of a HP5528 laser interferometer system. Having employed the surface painting technique, the shape error of the copied object relative to its master piece was found within 3

27、0 micrometers, which is deemed adequate enough to the mold industry.</p><p>　　1. INTRODUCTION</p><p>　　Since the first coordinate measuring machine (CMM) was developed by the Ferranti company of

28、 UK in 1960, the measuring efficiency of dimensional metrology has been greatly improved in industry. Conventionally, most CMMs are equipped with the touch-trigger probes for contact type of measurement on geometrical el

29、ements, such as line, plane, circle, cylinder, sphere, cone, etc. The measuring process is indeed very fast and repeatable with respect to the above elements since it needs only a limited n</p><p>　　. the sp

30、eed is not fast enough due to repetitive motion into and out of the surface,</p><p>　　. the sampled position is affected by the probing speed,</p><p>　　. the sampled points may not be adequate e

31、nough to represent the measured surface accurately,</p><p>　　. the technique of probe radius compensation is more difficult,</p><p>　　. the probe tip is subject to be worn quickly, and</p>

32、<p>　　. some dynamic errors of the machine structure and the servo controller may occur.</p><p>　　In order to improve the above-mentioned drawbacks, some laser probes have been developed for non-conta

33、ct measurement of free-form surfaces during the past years'4. In addition, when applying this kind of probe to the CNC type of CMM, the system accuracy and the measuring speed can be significantly increased5'6, a

34、nd the CAD/CAM integration can be easily achieved for the purpose of reverse engineering7'8.</p><p>　　This paper describes the work which employed a low cost laser probe to a DCC (Direct Computer Control

35、led) type CMM to develop an automatic non-contact measuring system for 3D free-form surfaces, and its integration with some PC based CAD/CAM softwares for reverse engineering. Such technique was also applied to a CNC mac

36、hining center to build up an on-machine measurement system. An in-depth calibration of the laser probe was primarily investigated with respect to the material, the surface slope, </p><p>　　2. OPERATING PRINC

37、IPLE OF LASER PROBE</p><p>　　The laser probe used in this study is a Keyence LC-2220 sensor head with LC-2100 controller. This low cost and visible laser probe provides displacement measurement via laser tri

38、angulation technique. As seen in Fig. 1, the focused laser beam emitted from the semiconductor laser is projected onto the object surface. Due to the surface roughness, the reflected beam will be scattered and partly col

39、lected by the laser receiving lens. Through this lens, the beam will be focused and projected onto the</p><p>　　3. PERFORMANCE TESTS OF LASER PROBE</p><p>　　For all of the non-contact type displ

40、acement sensors, such as the eddy current type, the ultrasonic type, the pneumatic type, and the laser beam reflected type, their performance curves are related to the surface properties of the tested objects. Some impor

41、tant parameters of the surface property with respect to the laser probe may include the material, the color, the roughness, and the slope of the object surface. Most of the specifications of laser probes, however, do not

42、 provide sufficient inf</p><p>　　3.1 System Set-up for Laser Probe Calibration</p><p>　　Fig. 2 shows the experimental set-up for this laser probe calibration system. The laser probe to be calibr

43、ated was mounted on the spindle head of a coordinate measuring machine (CMM, DCC type, Numerex Co.). The tested specimen was placed on a sine bar. The angle and the elevation of the sine bar can be adjusted by the gage b

44、locks and the jack respectively. A HP5528 laser interferometer was adopted to provide reference displacement in comparison with the laser probe output. The spindle could be m</p><p>　　3.2 Calibration Results

45、</p><p>　　Numerous calibrated data were collected with respect to different specimen conditions. Fig. 3a illustrates a typical diagram of displacement errors of the investigated laser probe with respect to t

46、he bakelite specimen in its original color (brown) , and with its surface normal to the laser beam. It was found that within the measuring range (±2mm) the maximum displacement error was —l8pm, but the repeatability

47、 and the reversal error were both very good. Fig. 3b plots its linearity curve with resp</p><p>　　Similar studies were also carried out with respect to an aluminum alloy specimen and a steel specimen separat

48、ely. In addition, the influence of surface colors on the laser probe's performance was studied by uniformly painting different colors on the tested surface. Table 2 summarizes calibrated results of the laser probe wi

49、th respect to the aluminum alloy at different slopes and in different surface colors. A significant phenomenon was found here that, regardless of the changes in the surface sl</p><p>　　The influence of the s

50、urface roughness of the workpiece on the laser probe measurement had already been investigated previously". It was found that within the reasonable Ra values (0.4 to 3 pm) of any machined surface, the calibrated res

51、ults did not show significant changes as long as the optical plane of the laser probe was perpendicular to the surface lay. Since most of the workpieces to be measured must have been polished to certain small Ra values,

52、this effect could therefore be neglected.</p><p>　　4. ENHANCEMENT OF EDGE DETECTION CAPABILITY OF LASER PROBE</p><p>　　Most of the laser probes on the market only provide the function of displac

53、ement measurement. Although this function can make the technique of surface scanning measurement possible, the capability of most laser probes in the edge detection is still very poor nowadays. Some solutions, in this te

54、chnology, will have to come about since any geometrical shape of the workpiece must have boundary. A method for this aspect is therefore proposed in this work.</p><p>　　The investigated laser probe, Keyence

55、LC-2220 sensor head with LC-2100 controller, has both digital and analog output ports. The digital port transmits its digital readouts to an external device via a RS-232C or a GPIB interface. Meanwhile, the analog port s

56、ends a voltage value in proportion to the meter reading out to an external A/D converter. As the laser probe is ou of its measuring range, the invalid region, the digital readout (DRO) will appear a "DARK" sign

57、al and the analog port will outp</p><p>　　An initial experiment was carried out by setting the laser probe, on the 0MM, at its reference distance to a flat work surface. It was then moved in and out of the s

58、urface horizontally and repeatedly, as seen in Fig. 5. The voltage changes of the analog signals were observed by a digital oscilloscope. Fig. 6 shows a typical display of the voltage changes when crossing the sharp edge

59、 of the work surface. It was clearly seen that when moving the probe from the invalid region into the valid region </p><p>　　To verify this enhanced capability of the laser probe in the edge detection, dimen

60、sional measurements were carried out on a line and a circle separately. Fig. 7a and Fig. 7b show each proposed measuring path. Fig. 8a and Fig. 8b plot the measured results which are all quite consistent with the corresp