CNC機(jī)床或坐標(biāo)測(cè)量機(jī)外文文獻(xiàn)翻譯、中英文翻譯、外文翻譯,CNC,機(jī)床,坐標(biāo),測(cè)量,外文,文獻(xiàn),翻譯,中英文 附錄一 CNC機(jī)床或坐標(biāo)測(cè)量機(jī) 這論文描述在CNC機(jī)床或坐標(biāo)測(cè)量機(jī)（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(gè)非連絡(luò)類型自動(dòng)機(jī)械測(cè)量系統(tǒng)的工作。 一個(gè)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(jī)器之內(nèi)。已經(jīng)發(fā)展了一個(gè)為任何自由形態(tài)輪廓的自動(dòng)表面追蹤的測(cè)量軟件。對(duì)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(guò)正確的DXF文件,也是可得的。 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(cè)方面,激光探測(cè)的系統(tǒng)精確方面已經(jīng)實(shí)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(duì)于它的樣品，不超過(guò)30微米，對(duì)于鑄型業(yè)應(yīng)該是足夠了。 自從1960年，英國(guó)的Ferranti公司發(fā)展了第一部坐標(biāo)測(cè)量機(jī)(CMM)，空間度量衡學(xué)的測(cè)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(cè)量。測(cè)量的程序在以上因素方面的確非?？於铱芍貜?fù)，因?yàn)橹恍枰綔y(cè)點(diǎn)的少數(shù)數(shù)字，而且探測(cè)半徑的補(bǔ)償是相當(dāng)簡(jiǎn)單的。然而當(dāng)3D自由形態(tài)表面測(cè)量的需要近幾年來(lái)增加，尤其隨著反向工程的鑄型業(yè)，當(dāng)在很多測(cè)量點(diǎn)方面應(yīng)用接觸探測(cè)時(shí)，許多缺點(diǎn)被發(fā)現(xiàn)。一些典型的問(wèn)題是：由于重復(fù)的進(jìn)出表面的運(yùn)動(dòng)， 速度不是夠快。被抽取樣品的位置因探測(cè)速度而影響，被抽取樣品的點(diǎn)可能不夠適當(dāng)來(lái)正確地表現(xiàn)標(biāo)準(zhǔn)的表面，探頭頂尖的半徑補(bǔ)償更難。探頭頂尖容易很快磨損，而且一些機(jī)械結(jié)構(gòu)和伺服控制器的誤差可能會(huì)發(fā)生。 為了改善上述缺點(diǎn)，在過(guò)去四年，有些激光探頭已經(jīng)開發(fā)出來(lái)，用于自由曲面的非接觸式測(cè)量。此外，在應(yīng)用這種探針到CNC型的CMM時(shí)，系統(tǒng)的測(cè)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(shí)現(xiàn)其逆向工程的目的。 這論文描述使用了一個(gè)低成本激光探針到一個(gè)DCC（直接的計(jì)算機(jī)控制）型的CMM來(lái)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(gè)自動(dòng)的非接觸測(cè)量系統(tǒng)。如此的技術(shù)也被適用于 CNC機(jī)器中心來(lái)建立一個(gè)機(jī)器測(cè)量系統(tǒng)。激光的一個(gè)深入口徑測(cè)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(cè) 量工件的邊緣檢測(cè) 。在使用表面涂層技術(shù)后，再生產(chǎn)的工件形狀誤差相對(duì)于它的主件在 30jrn 之內(nèi)， 這個(gè)誤差對(duì)于模具業(yè)的要求應(yīng)該是足夠的。2激光探針的工作原理。 用于此項(xiàng)研究的激光探針是一個(gè)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(guò)激光三角提供位移測(cè)量技術(shù)。正如所示，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(guò)激光接收鏡頭部分收集。通過(guò)這個(gè)鏡頭，光束將集中和投影到位置敏感探測(cè)器(PSD)的傳感器頭。如果被測(cè)量物體移動(dòng)(Lx,圖中), 反射激光光斑也通過(guò)PSD手段移動(dòng)。然后，這點(diǎn)位移通過(guò)這里也被稱為控制器的數(shù)據(jù)處理轉(zhuǎn)換為一個(gè)模擬或數(shù)字信號(hào)。最后，該控制器進(jìn)行數(shù)據(jù)處理，如線性補(bǔ)償和平均值計(jì)算，顯示和輸出測(cè)量結(jié)果。 所有的非接觸式位移傳感器，如渦流型，超聲波型，氣動(dòng)型，激光束反映類型，它們的性能曲線都與測(cè)試對(duì)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，以及物體表面的斜坡。大多數(shù)激光探測(cè)器的規(guī)格，然而，業(yè)務(wù)手冊(cè)中沒(méi)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(diǎn)的數(shù)據(jù)通常沒(méi)有直接適用于特定的加以衡量的對(duì)象。因此，首要的工件方面的激光探針必須被采用以保證測(cè)量結(jié)果更準(zhǔn)確。 顯示了激光探針標(biāo)定系統(tǒng)實(shí)驗(yàn)裝置。進(jìn)行校準(zhǔn)的激光探針是安裝在三坐標(biāo)測(cè)量機(jī)(CMM, DCC 類型, Numerex 有限公司）。那個(gè)測(cè)試試樣放在一個(gè)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(duì)于激光探針輸出的丟失。主軸可由計(jì)算機(jī)逐步移至向上和向下。因此， 一旦開始，這個(gè)校準(zhǔn)任務(wù)可根據(jù)德國(guó)工程師協(xié)會(huì)3441標(biāo)準(zhǔn)自動(dòng)處理。而且每個(gè)操作被運(yùn)行五次雙方向的行進(jìn)。各種實(shí)驗(yàn)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，黃色著色）， 和表面粗糙度(0.4pm到3pm)的試樣條件調(diào)查序列。 眾多的校準(zhǔn)數(shù)據(jù)是不同的試樣條件方面收集的。說(shuō)明了研究電木標(biāo)本方面典型圖位移誤差，其原來(lái)的顏色（棕） ，和有激光束的表面。結(jié)果發(fā)現(xiàn)，在測(cè)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(cuò)誤都非常好。圖 3 b它的直線性有最少－角尺線彎曲?？偨Y(jié)在同樣的條件下五個(gè)測(cè)試結(jié)果。一個(gè)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(shuō)，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(yuǎn)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(qiáng)度會(huì)降低,這將導(dǎo)致低信號(hào)噪聲(S/N)。 因此，線性度會(huì)越來(lái)越差。然而，幸運(yùn)的是，重復(fù)性仍然和以前一樣好(在2pm之內(nèi))。 類似的研究也分別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(guò)在被測(cè)試的表面上涂不同的顏色來(lái)研究.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(gè)重要現(xiàn)象是,無(wú)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(cè)量精度. 在激光探針測(cè)量時(shí),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(méi)有表現(xiàn)出顯著的變化.由于大多數(shù)測(cè)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(jì)。大多數(shù)市場(chǎng)上的激光探針只提供位移測(cè)量的功能. 雖然這一功能可以使表面描測(cè)量的技術(shù)成為可能,但大多數(shù)激光探針在邊緣檢測(cè)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(huì)發(fā)生, 因?yàn)槿魏螏缀涡螤畹墓ぜ仨氂羞吔?。一種這方面的方法在這項(xiàng)工作中被提議. 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(guò)RS - 232C接口或GPIB接口為外部設(shè)備傳輸數(shù)字讀數(shù). 同時(shí)，類似端口按比例發(fā)送一個(gè)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(cè)量范圍之外,無(wú)效的地區(qū),數(shù)字讀出(DRO）會(huì)出現(xiàn)一個(gè)“黑色”的模擬信號(hào)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(duì)于表面的參考距離, 模擬信號(hào)將輸出電壓零。 最初的實(shí)驗(yàn)在CMM上單位工作表面上的參考距離通過(guò)設(shè)置激光探針進(jìn)行的. 然后水平地而且重復(fù)地被移動(dòng)進(jìn)移動(dòng)出表面,如圖5所示.模擬信號(hào)的電壓變化通過(guò)數(shù)字示波器觀察到.顯示了一個(gè)典型展示,當(dāng)通過(guò)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(wú)效區(qū)域到有效的區(qū)域,輸出信號(hào)出現(xiàn)明顯 和進(jìn)給速度成正比的延遲時(shí)間.然而，當(dāng)從有效區(qū)域到無(wú)效區(qū)域移動(dòng)探針時(shí),在邊緣地區(qū)輸出信號(hào)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(gè)可行的解決辦法，該邊緣檢測(cè)應(yīng)該從有效的區(qū)域到無(wú)效的區(qū)域做到.另一個(gè)重要因素還應(yīng)當(dāng)指出是,光學(xué)平面的運(yùn)動(dòng)必須垂直于表面位置,否則光將嚴(yán)重分散。為了驗(yàn)證激光探針中的邊緣檢測(cè)的增強(qiáng)的能力,三維測(cè)量在一條線和一個(gè)圓分別測(cè)量. 顯示每個(gè)被提議的測(cè)量路徑. 圖8A和圖8B測(cè)量結(jié)果都非常符合相應(yīng)的標(biāo)稱尺寸。 對(duì)被提議的工具路徑傳用和控制方法的概要描述是描述在圖7中。在被提議的方法中，合成物剪裁者聯(lián)絡(luò)數(shù)據(jù)，包括CC位置和表面原則常態(tài)（N）的云形規(guī)功能，預(yù)先設(shè)定CC速度（Vc ），和工具傾向及傾斜角度（Φ和λ），與CNC機(jī)器聯(lián)系。在CNC內(nèi)插器中，CL路徑是被計(jì)算為在真正的時(shí)間內(nèi)沿著CC路徑所需要的CC速度。綜上，彌補(bǔ)運(yùn)算法則的刀具是在CNC內(nèi)插器中實(shí)現(xiàn)的。 一個(gè)環(huán)型的反饋圈被內(nèi)插器所封閉，這個(gè)反饋圈能檢測(cè)到在真正時(shí)間里的實(shí)際的CC位置（ C* ），以及需償還的偏離指定CC路徑的錯(cuò)誤。除此之外，在線的改編的同盟（i.e CC速度）是介紹增加機(jī)制準(zhǔn)確性和效率。舉例來(lái)說(shuō)，當(dāng)CC偏離錯(cuò)誤大量增加時(shí)我們可以降低機(jī)制（通過(guò)降低Vc ）以及當(dāng)偏離錯(cuò)誤可以忽略時(shí)加速機(jī)制（通過(guò)減少Vc ）。注意一些變數(shù)同盟（適當(dāng)?shù)卦诰€逐漸增加減退的Vc ） 僅僅在它在其他同盟-受扶者切斷效果時(shí)不引起無(wú)法接受的降格時(shí)被保留，這些 切斷效果就是像切斷時(shí)間，工具包裝，表面正直，等等。對(duì)被提議的工具路徑傳 用和控制方法需要的運(yùn)算法則被呈現(xiàn)在下列各項(xiàng)。 CC 的路徑竄改，剪裁彌補(bǔ)和倒轉(zhuǎn)的運(yùn)動(dòng)學(xué)轉(zhuǎn)變給內(nèi)插器的核心功能是CC路徑竄改，剪裁彌補(bǔ)和倒轉(zhuǎn)的運(yùn)動(dòng)學(xué)的轉(zhuǎn)變。讓為CC位置（C）和表面原則常態(tài)（N） 所提供的云行規(guī)功能是通過(guò)以下公式表述出來(lái)的。所用的u是云行規(guī)向前空間的參數(shù)。 在上段決定了的竄改運(yùn)算法則是在這里應(yīng)用。因?yàn)檫@個(gè)竄改法則是引導(dǎo)CC 的輸出路徑而非CL的路徑。為符合CC路徑，公式中的t需要用c來(lái)替換。此外，在式中的CL路徑的速度（Vl ）需要被CC路徑的速度（Vc ）來(lái)替換。 在式彌補(bǔ)運(yùn)算法則的刀具對(duì)及時(shí)的刀補(bǔ)是適當(dāng)?shù)摹Ｔ谑阶?B = T ′ N 中的沿 著CC路徑的單位矢量T可以通過(guò)下面的式子計(jì)算出來(lái)通過(guò)刀具補(bǔ)償，刀具位置和定方向是可得的。根據(jù)式子（5c）的描述，基于倒轉(zhuǎn)的運(yùn)動(dòng)學(xué)是可轉(zhuǎn)變的，我們把參考指令給5軸的動(dòng)軸，R。 附加到上方的核心功能的還有，兩個(gè)可選的功能包括，一個(gè)是在真正的時(shí)間里CC路徑的偏離錯(cuò)誤，另一個(gè)是被介紹為改變CC的速度來(lái)增加控制表現(xiàn)的。這兩個(gè)功能都是基于實(shí)際CC點(diǎn)的，即C* 。在典型的5軸工作母機(jī)運(yùn)動(dòng)控制中，可得的 回應(yīng)數(shù)據(jù)是沿著這5個(gè)軸的輸出位置?；谠冢?a）和（4b）中提及的運(yùn)動(dòng)學(xué)轉(zhuǎn)變?cè)恚覀円老铝懈黜?xiàng)可以得到實(shí)際的剪裁位置（ L* , O* )。 根據(jù)式可以計(jì)算出實(shí)際CC點(diǎn)C* 對(duì)應(yīng)的是（ L* , O* ）練習(xí)倒轉(zhuǎn)的刀具彌補(bǔ)。 因?yàn)樗▽?shí)際傾向的計(jì)算和傾斜角度（f* 和l* ）的定義有關(guān)于TNB的框架，所 以倒轉(zhuǎn)的形成非常復(fù)雜。在下列各項(xiàng)中，提議了一個(gè)簡(jiǎn)單但是有效的運(yùn)算法則。從幾何學(xué)角度看，CC錯(cuò)誤， C* - C 是CL錯(cuò)誤的重疊， L* - L ，以及刀具定位錯(cuò)誤 O* - O 。設(shè)Ψ偏離刀具軸，U是沿著Ψ的旋轉(zhuǎn)方向的單位矢量。因?yàn)镃C點(diǎn)是一個(gè)固定在刀具上的點(diǎn)，我們有式中 注意式僅適用于當(dāng)Ψ與l比足夠小的時(shí)候。然而這種情況對(duì)常態(tài)的5軸的工作 母機(jī)運(yùn)動(dòng)控制總是真實(shí)的。（注意在以后的模擬例子中，對(duì)于Ψ的典型價(jià)值是少于0.005rad）。 可以看出，CC路徑偏離錯(cuò)誤，δ，是指從C* 到指定的表面的距離，這個(gè)是我們關(guān)注的部分，因?yàn)樗苯記Q定機(jī)制錯(cuò)誤。偏離錯(cuò)誤可以接近地表示為 注意偏離錯(cuò)誤的方向是在表面常態(tài)，也就是δ=δN。 在抽取樣品kh中分別是參考CC位置的初始和償還值。 在實(shí)際運(yùn)動(dòng)控制中除去或者補(bǔ)償偏離錯(cuò)誤，在抽取樣品時(shí)參考CC位置可以用下式來(lái)修正 k k 式中C 和Ccomp Kp 是比 例控制增益的補(bǔ)償環(huán)。注意其他控制規(guī)律（舉例來(lái)說(shuō)比例的控制，領(lǐng)引-落后的控制，等等）可以被介紹為被第二段的所替代。當(dāng)然，在這里一些簡(jiǎn)單的比例控制也是需要考慮在內(nèi)的?？刂频玫?， Kp ，必須是能夠有效地減少δ和維持系統(tǒng) 的穩(wěn)定。在后面的說(shuō)明例子中，Ziegler-Nichols 終極-敏感的方法[23]被利用來(lái)決定 Kp 回饋圈的另一個(gè)作用就是收益一個(gè)沿著CC路徑的變數(shù)進(jìn)給以此來(lái)改善機(jī)制的準(zhǔn)確性和效率。在此期間，我們可以減少Vc 作為δ的增加，這個(gè)方法就是減慢機(jī)制就像藉由δ的表示改善機(jī)制的準(zhǔn)確性一樣。另一方面，我們?cè)黾覸c 可以以δ 為基礎(chǔ)，我們有Vc =Vc (δ)。在實(shí)踐中，僅僅當(dāng)機(jī)制增加時(shí)間是允許的時(shí)候減 速是能夠被獲得。此外，僅僅當(dāng)加速在其他進(jìn)給-依賴切斷效果（像工具外表， 表面正直，等等）不引起無(wú)法接受的降格時(shí)才考慮它。在后面說(shuō)明的例子中，在線的同盟改編焦點(diǎn)是改良機(jī)制的準(zhǔn)確性（也就是減少δ）。 在下面的示范中，一個(gè)規(guī)定的表面是生產(chǎn)5軸的機(jī)制。規(guī)定表面有下列各項(xiàng)參數(shù)的形式 提及了工作母機(jī)的幾何學(xué)參數(shù)是( lx , ly , lz )=(0,0,500)毫米和bz =200毫米。最 后利用rt = 5毫米和rc = 0毫米。那需要的是進(jìn)給是10mm/s。CC路徑是預(yù)設(shè)在u方 向上而路徑間隔v方向。工具軸分配為Ф=20°和λ=0（注意傾向角度Φ一定比17.9°大這樣才能避免后面凹的范圍的精確計(jì)量）。顯示了加工過(guò)的表面和一條特殊的CC路徑，C(u)，沿用v=0和它對(duì)應(yīng)的CL路徑，L(u) 和O(u)。 在傳統(tǒng)的方法中，CC數(shù)據(jù)，L（u）和O(u)連同CL速度Vl ，都被輸入到CNC內(nèi)插器中用以及時(shí)的剪裁。注意此處CL的速度Vl 作為進(jìn)給速度設(shè)定為10mm/s?；谏厦娴臄?shù)據(jù)以及在式提到的內(nèi)插器運(yùn)算法則，剪裁路徑是能產(chǎn)生在線機(jī)制的。然而，當(dāng)做CC速度Vc 檢查時(shí)，我們能夠發(fā)現(xiàn)沿著刀具路徑Vc 的改變（Vc 的變化超過(guò)了10%）。變量Vc 導(dǎo)致非固定機(jī)制的質(zhì)量和效率。 和上面的問(wèn)題結(jié)合，被提議的工具路徑傳用方法，可以被介紹為決定上面的 區(qū)段。在被提議的方案中，CC數(shù)據(jù)，C（u）和N(u)，連同被設(shè)定為10mm/s的CC 速度，全部被輸入到CNC內(nèi)插器中。因?yàn)楣ぞ呗窂降膫饔檬腔谝粋€(gè)固定的Vc ， 一個(gè)常數(shù)沿著CC路徑是容易被控制的。 為了要了解5軸的機(jī)制，機(jī)制工具同時(shí)受到驅(qū)策3滑和兩個(gè)回轉(zhuǎn)的軸。每個(gè)軸 的運(yùn)動(dòng)是根據(jù)伺服促使電機(jī)運(yùn)轉(zhuǎn)和軸控制器的控制。在下面的模擬方面，數(shù)學(xué)型號(hào)（在s領(lǐng)域）的選擇[23]是根據(jù)電機(jī)受到驅(qū)策的伺服機(jī)制 式中i=x,y,z,а,в。在上面的等式中，si 和ti 分別是每個(gè)軸的驅(qū)動(dòng)的增益和時(shí)間常數(shù)。si 的值和ti 在模擬方面的應(yīng)用列在。 系統(tǒng)參數(shù)在模擬方面的應(yīng)用樣本抽取時(shí)期: h=0.002 s 軸的增益和時(shí)間常數(shù)（s） 典型的比例-整體-引出的控制規(guī)律是被軸的控制器所利用。控制器的移動(dòng)功能（z-領(lǐng)域）被[22]所描述 式中 H p ， Hi ， Hd 分別地是比例，整體和引出增益。 H p ， Hi ， Hd 的值在表格1中可以計(jì)算出來(lái)。 為了達(dá)到有效的CC路徑控制，為CC偏離錯(cuò)誤構(gòu)造一個(gè)環(huán)型的回饋圈，用δ作補(bǔ)償。基于式?jīng)Q定的系統(tǒng)參數(shù)和運(yùn)算法則，由此可見，被提議的補(bǔ)償方法可以有效地減少δ。此外， 錯(cuò)誤減少的因素和償還成比例增益， Kp .( Kp >8)。Ziegler-Nichols終極-敏感方法大約是4，哪一個(gè)符合就減少一個(gè)5的δ。 一個(gè)及時(shí)的進(jìn)給運(yùn)算法則是家少改善CC路徑控制的準(zhǔn)確性的。用來(lái)旋轉(zhuǎn)CC 的速度的適當(dāng)方法比如適合的控制和模糊邏輯控制，這些在下面有所描述。 If dk If dk > dd ,V k =hV k -1 c c c c < dr ,V k = xV k -1 (deceleration) (recovery) c c c c If V k > V o ,V k = V o  (maximum or preset speed) V k < V ,V k = V If c min c min (minimum speed) V k 在上面的規(guī)則中， c 和V k -1 分別是kh 和(k-1)h的速度指令，δk是在時(shí)間 c kh 中有計(jì)劃的路徑偏離錯(cuò)誤。η和ξ分別是句頂速度減速的比率和恢復(fù)的因素。 V V V o V c 是在 min 和 c 范圍之內(nèi)的。在實(shí)踐中，預(yù)先設(shè)定CC的速度是 c (=10mm/s)。 在 下 面 的 模 擬 中 ， 我 們 設(shè) 置 這 些 參 數(shù) 是 ： η =0.99, ξ =1.01, dd =0.01mm,dr =0.0075mm, Vmin =5 mm/s?；谏厦娴乃俣雀木庍\(yùn)算法則，模擬5 軸運(yùn)動(dòng)，結(jié)果在兔13中顯示。隨著這些提議的方法，偏離錯(cuò)誤在速度改編區(qū)域期間是減少的。然而，機(jī)制時(shí)間增加了0.1s。 對(duì)于5軸的機(jī)制申請(qǐng)，我們主要關(guān)心的部分是在刀具聯(lián)絡(luò)速度和沿著刀具方向除去偏離錯(cuò)誤聯(lián)絡(luò)路徑上，而不是刀具位置速度和傳統(tǒng)刀具控制路徑和方法上。為了處理這些擔(dān)心，一種新的方法呈現(xiàn)出來(lái)，就是及時(shí)的刀具路徑傳用和控制。 被提議的刀具路徑傳用方法是刀具-聯(lián)絡(luò)路徑的竄改，刀補(bǔ)包含及時(shí)的運(yùn)算法則，和同等的關(guān)系轉(zhuǎn)變。隨著這些方法的提出，刀具路徑傳用以此來(lái)滿足沿著剪裁路徑的需要速度對(duì)表面的加工。 為了改善在實(shí)際5軸的機(jī)制中的受約束的準(zhǔn)確性，構(gòu)造另一個(gè)環(huán)型回饋圈用CNC內(nèi)插器關(guān)閉。環(huán)型反饋中，被關(guān)注的沿著刀具路徑的偏離錯(cuò)誤在在線機(jī)制中可以計(jì)算出來(lái)?；诃h(huán)型回饋圈，補(bǔ)償運(yùn)算法則介紹的是直接和有效地去除偏離錯(cuò)誤。此外，如果機(jī)制時(shí)間的增加是允許的，我們可以得到一個(gè)進(jìn)給的改編運(yùn)算法則，當(dāng)偏離錯(cuò)誤太大是這個(gè)運(yùn)算法則可以用來(lái)減少速度。模擬結(jié)果已經(jīng)顯示錯(cuò)誤補(bǔ)償方法的效力和適當(dāng)?shù)倪M(jìn)給改編方法。然而，未來(lái)在運(yùn)算法則上的研究或者規(guī)則錯(cuò)誤補(bǔ)償和進(jìn)給的改編是推薦的。 附錄二  CNC machine toolor CMM This paper describes the work to develop a non-contact type automatic measurement system for any free-form surfaces on a CNC machine tool or a coordinate measuring machine (CMM), and its CAD/CAM integration. A laser probe, made by Keyence Co. model LC-2220, was integrated 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 engineering is also available via proper DXF file. Extensive calibration work has been carried out on the systematic accuracy of the laser probe with respect to the color, material, surface slope, 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 30 micrometers, which is deemed adequate enough to the mold industry. Since the first coordinate measuring machine (CMM) was developed by the Ferranti company of 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 elements, 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 number of probing points and the probe radius compensation is quite straightforward. However, as the demands for 3D free-form surface measurements are increasing in recent years, especially by the mold industry for reverse engineering, many disadvantages have been discovered when applying the contact probe for numerous measuring points. Some typical problems are: the speed is not fast enough due to repetitive motion into and out of the surface, the sampled position is affected by the probing speed, the sampled points may not be adequate enough to represent the measured surface accurately, the technique of probe radius compensation is more difficult,\the probe tip is subject to be worn quickly, and\some dynamic errors of the machine structure and the servo controller may occur. In order to improve the above-mentioned drawbacks, some laser probes have been developed for non-contact 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, and the CAD/CAM integration can be easily achieved for the purpose of reverse engineering7'8. This paper describes the work which employed a low cost laser probe to a DCC (Direct Computer Controlled) 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 machining 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, the color, and the edge detection of the workpiece to be measured. Having employed the surface painting technique, the shape error of the reproduced workpiece relative to its master piece was found within 30 jrn, which is deemed adequate enough to the requirement by the mold industry. 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 triangulation 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 collected by the laser receiving lens. Through this lens, the beam will be focused and projected onto the position sensitive detector (PSD) in the sensor head. If the object to be measured moves (Lx, in the figure), the reflected laser light spot also moves (6) by means of the PSD. Then, this spot displacement is converted to an analog or a digital signal through a data processing unit which is also called the controller here. Finally, the controller carries out data processing, such as linearity compensation and average value calculation, displaying and outputting the measured results. For all of the non-contact type displacement 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 important 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 provide sufficient information in the operational manuals. The listed data reflecting the performace characteristics of any particular laser probe provided by the manufacturer uaually are not directly applicable to a particular object to be measured. Therefore, primary accuracy calibration of the adopted laser probe with respect to the adopted workpiece has to be carried out in order to guarantee the measured results more accurately. Fig. 2 shows the experimental set-up for this laser probe calibration system. The laser probe to be calibrated 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 blocks 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 moved up and down step-by-step by the computer commands. Therefore, once initiated, this calibration task could be processed automatically according to the VDI 3441 standard° , and five times bi-directional travels were executed for each task. Various experiments were then investigated in sequence by changing different specimen conditions, such as materials (steel, aluminum alloy, and bakelite), slopes (0 to 60 degrees in steps), colors (original, and white, red, yellow paintings), and surface roughnesses (0.4 pm to 3 pm). 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 the 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 and the reversal error were both very good. Fig. 3b plots its linearity curve with respect to the least-squares line. Table 1 summarizes five tested results at similar specimen condition except with different surface slopes. An interesting phenomenon can be seen that as the surface slope increases the displacement error increases too. It can be explained that the scattered light on the object surface performs a Gaussian distribution along the specular direction'°, as shown in Fig. 4. As the surface normal is moving away from the laser beam axis, the intensity of the reflected beam collected by the light receiving lens in the sensor head is decreasing which will result in low signal-to-noise ratio (S/N). Consequently, the linearity will get worse. However, fortunately, the repeatability still remains as good as before (within 2pm). Similar studies were also carried out with respect to an aluminum alloy specimen and a steel specimen separately. 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 with 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 slope, the red surface could always ensure the laser probe with very good accuracy performance. As the aluminum alloy specimen was replaced by the steel specimen, similar conclusion could still be obtained, as seen in Table 3. From these studies, a suggestion can be given to the mold making industry that, while producing the mold by the reverse engineering technique with a laser probe, the measuring accuracy can be significantly improved if the master piece is coated with red paint. The influence of the surface 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 results 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, this effect could therefore be neglected. Most of the laser probes on the market only provide the function of displacement 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 technology, 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. The investigated laser probe, Keyence 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 sends 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" signal and the analog port will output 6.55 volts. As the laser probe is located within its valid region and at its reference distance to the surface, the analog signal will output zero volt. 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 surface 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 of the work surface. It was clearly seen that when moving the probe from the invalid region into the valid region across the sharp edge the output signal appeared an apparent time delay which was proportional to the feedrate. However, when moving the probe from the valid region to the invalid region the output signal responded immediately at the edge position. This phenomenon is difficult to explain. Yet, the authors believe that it could be due to the triangulation principle of the laser probe. It, however, points out a feasible solution that the edge detection should always be done from the valid region to the invalid region. Another important factor should also be pointed out here that, during motion the optical plane must be perpendicular to the surface lay, otherwise the light will be seriously scattered out. To verify this enhanced capability of the laser probe in the edge detection, dimensional 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 corresponding nominal dimensions. A schematic description for proposed tool path generation and control method is depicted in Fig.7.In the proposed method., composite cutter contact data, which include the spline functions for the CC location (C) and the surface principle normal (N), the preset CC velocity ( Vc ),and the tool inclination and tilt angles(Φandλ),are loaded to the CNC machine .In the CNC interpolator, the CL path is calculated in real time so as to meet the desired CC velocity along the CC path. Consequently, the cutter offsetting algorithm is implemented in the CNC interpolator. As is shown in Fig.7, a global feedback loop is closed by the interpolator, which can monitor the practical CC location ( C* ) in real time and compensate for the deviation error from the desired CC path. In addition, on-line adaptation of the federate (i.e the CC velocity) can be introduced