外文翻譯--機(jī)械裝備的發(fā)展

1、<p><b>　　機(jī)械裝備的發(fā)展</b></p><p><b>　　一．機(jī)械裝備的應(yīng)用</b></p><p>　　近十幾年來(lái)，隨著計(jì)算機(jī)技術(shù)和現(xiàn)代控制理論等相關(guān)科技的迅速發(fā)展，以數(shù)控加工為代表的柔性加工日趨完善，基本上實(shí)現(xiàn)了自由曲面形狀加工階段的自動(dòng)化，但其精加工主要還依靠熟練工人的手工操作。由于手工操作生產(chǎn)效益低下，加工質(zhì)量不穩(wěn)

2、定，難以適應(yīng)自由曲面低成本、短周期、高質(zhì)量的要求，研究一種高效自動(dòng)化的研拋設(shè)備勢(shì)在必行，本研究針對(duì)自由曲面研拋加工所開(kāi)發(fā)的虛擬軸混聯(lián)機(jī)床就是為了適應(yīng)這種需求。</p><p><b>　　二．狀態(tài)分析</b></p><p>　　本處所開(kāi)發(fā)的是并聯(lián)、串聯(lián)有層次聯(lián)結(jié)在一起的混聯(lián)機(jī)床。通過(guò)大量文獻(xiàn)閱讀，建立了各種并聯(lián)機(jī)構(gòu)模型，運(yùn)用 Adams 軟件對(duì)各種并聯(lián)機(jī)構(gòu)模型進(jìn)行分

3、析，證明了3PTT運(yùn)動(dòng)副可以實(shí)現(xiàn)動(dòng)平臺(tái)三維空間運(yùn)動(dòng)。</p><p>　　用 Adams 軟件建立的該機(jī)床并聯(lián)機(jī)構(gòu)模型，并進(jìn)行自由度問(wèn)題研究和動(dòng)平臺(tái)的運(yùn)動(dòng)分析。仿真結(jié)果表明，該并聯(lián)機(jī)構(gòu)具有三個(gè)自由度，動(dòng)平臺(tái)是平動(dòng)的運(yùn)動(dòng)狀態(tài)。</p><p>　　三、自由曲面研拋機(jī)床的位姿分析</p><p>　　根據(jù)該機(jī)車的運(yùn)動(dòng)特性，利用解析法建立并聯(lián)機(jī)構(gòu)的正解方程，首先建立并聯(lián)機(jī)

4、構(gòu)的解析圖形，如圖2所示。</p><p>　　圖2 研拋機(jī)床并聯(lián)機(jī)構(gòu)解析圖</p><p><b>　　兩端取模平方知：</b></p><p>　　利用齊次變換的方法建立了自由曲面研拋機(jī)床串聯(lián)機(jī)構(gòu)的位置正解，并將串并聯(lián)機(jī)構(gòu)通過(guò)動(dòng)平臺(tái)為紐帶，得到機(jī)床的位置正解。運(yùn)用歐拉角表達(dá)研拋工具的軸線姿勢(shì)，發(fā)現(xiàn)該軸線姿勢(shì)只與串聯(lián)機(jī)構(gòu)有關(guān)，而與并聯(lián)機(jī)構(gòu)無(wú)關(guān)

5、。</p><p>　　四、自由曲面研拋機(jī)床的動(dòng)力學(xué)分析及其仿真</p><p>　　機(jī)床的動(dòng)力學(xué)研究，包括機(jī)構(gòu)慣性力計(jì)算、受力分析、動(dòng)力平衡、動(dòng)力學(xué)模型建立、計(jì)算機(jī)動(dòng)態(tài)仿真等。特別是在機(jī)器的運(yùn)行速度不斷提高的情況下，動(dòng)力學(xué)問(wèn)題的重要性就顯得尤為突出，由于計(jì)算機(jī)的不斷發(fā)展，使動(dòng)力學(xué)計(jì)算、分析、模擬的手段逐步實(shí)現(xiàn)了現(xiàn)代化。對(duì)機(jī)構(gòu)動(dòng)力學(xué)研究的深入，促進(jìn)了機(jī)器的運(yùn)轉(zhuǎn)速度進(jìn)一步提高，對(duì)機(jī)器的控制提

6、供較為精確的理論基礎(chǔ)。</p><p>　　五、自由曲面研拋機(jī)床結(jié)構(gòu)的研究</p><p>　　機(jī)床的研制分為二大部分：一是確定其機(jī)械結(jié)構(gòu)方案包括機(jī)床機(jī)架設(shè)計(jì)；動(dòng)平臺(tái)設(shè)計(jì)；終端執(zhí)行器設(shè)計(jì)等。二是研制控制電路和控制軟件等。機(jī)床應(yīng)有三個(gè)性能指標(biāo)：對(duì)稱性、工作空間、各向同性的基礎(chǔ)上來(lái)設(shè)計(jì)混聯(lián)機(jī)床。自由曲面研拋機(jī)床的主、俯視圖如圖 3 所示。</p><p>　　圖3

7、 自由曲面研拋機(jī)床的主、俯視圖</p><p><b>　　六、結(jié)論</b></p><p>　?。?）通過(guò)“3 并聯(lián)軸2 串聯(lián)軸”的五坐標(biāo)聯(lián)動(dòng)，用并聯(lián)機(jī)構(gòu)控制研拋工具的位置，用串聯(lián)機(jī)構(gòu)控制研拋工具的姿勢(shì)，有效地拓展了研拋加工作業(yè)空間。</p><p>　?。?）建立了 3PTT 并聯(lián)機(jī)構(gòu) ADAMS 機(jī)構(gòu)學(xué)模型，進(jìn)行了自由度問(wèn)題的研究。仿真

8、結(jié)果表明： 3PTT 并聯(lián)機(jī)構(gòu)是平動(dòng)的機(jī)構(gòu)。</p><p>　?。?）應(yīng)用解析法推導(dǎo)了機(jī)床的并聯(lián)機(jī)構(gòu)的位置正解；利用齊次變換的方法建立了自由曲面研拋機(jī)床串聯(lián)機(jī)構(gòu)的位置正解。運(yùn)用歐拉角表達(dá)研拋工具的軸線姿勢(shì)，發(fā)現(xiàn)該軸線姿勢(shì)只與串聯(lián)機(jī)構(gòu)有關(guān)，而與并聯(lián)機(jī)構(gòu)無(wú)關(guān)。</p><p>　　（4）基于影響系數(shù)理論與拉格朗日方程，推導(dǎo)出了串、并聯(lián)機(jī)構(gòu)動(dòng)力學(xué)方程，并建立了 ADAMS 動(dòng)力學(xué)仿真模型，仿真

9、結(jié)果表明：該機(jī)床在 x、y、z 三個(gè)方向上的速度、加速度差異很大。如果在 z 方向需要大的速度和加速度，三個(gè)滑塊均需加同一方向的力，數(shù)值相差要足夠小，在 x、y 方向需要較大的速度和加速度時(shí)，在三個(gè)滑塊上力的數(shù)值要相差足夠大。</p><p>　?。?）在自由曲面虛擬軸混聯(lián)研拋機(jī)床的結(jié)構(gòu)、運(yùn)動(dòng)學(xué)與動(dòng)力學(xué)研究以及前人關(guān)于研拋理論的工作基礎(chǔ)上，開(kāi)發(fā)了自由曲面虛擬軸混聯(lián)研拋機(jī)床的樣機(jī)。</p><p

10、>　　串-并混聯(lián)研拋機(jī)床運(yùn)動(dòng)與控制研究</p><p>　　1994 年在芝加哥國(guó)際機(jī)床展覽會(huì)（IMTS94）上，美國(guó)的 Ingersoll 和 Giddings & Lewi公司分別首次展出了名為 Hexapod 和 Variax 的并聯(lián)機(jī)床，引起舉世關(guān)注。并聯(lián)機(jī)床以空間并聯(lián)構(gòu)型為基礎(chǔ)，打破了近兩個(gè)世紀(jì)以來(lái)單一的以笛卡爾坐標(biāo)直線位移為基礎(chǔ)的串聯(lián)機(jī)床</p><p>　　結(jié)構(gòu)

11、和運(yùn)動(dòng)學(xué)原理，被譽(yù)為“本世紀(jì)機(jī)床機(jī)構(gòu)的最大變革與創(chuàng)新”、“21 世紀(jì)的機(jī)床”。其后，意大利、日本、俄羅斯、挪威、瑞士、瑞典、丹麥等國(guó)的制造商竟相研發(fā)并聯(lián)機(jī)床。1997 年底，清華大學(xué)和天津大學(xué)聯(lián)合研制出了我國(guó)第一臺(tái)并聯(lián)機(jī)床 VAMT1Y。</p><p>　　與傳統(tǒng)的串聯(lián)構(gòu)型機(jī)床相比，純并聯(lián)構(gòu)型的并聯(lián)機(jī)床在結(jié)構(gòu)及運(yùn)動(dòng)特性上具有剛度重量比大，運(yùn)動(dòng)部件質(zhì)量小、響應(yīng)速度快，誤差累積小，可以很容易地實(shí)現(xiàn) 6 軸聯(lián)動(dòng)，運(yùn)動(dòng)

12、學(xué)逆解求解容易、便于實(shí)現(xiàn)實(shí)時(shí)控制，機(jī)床結(jié)構(gòu)簡(jiǎn)單，技術(shù)附加值高等優(yōu)點(diǎn)。但并聯(lián)機(jī)床同時(shí)也存在著工作空間小，運(yùn)動(dòng)學(xué)的正解求解困難，控制復(fù)雜，各軸間存在著深度的非線性運(yùn)動(dòng)耦合，運(yùn)動(dòng)學(xué)標(biāo)定困難，機(jī)床的剛度和運(yùn)動(dòng)精度不高等缺點(diǎn)。為克服并聯(lián)機(jī)床的缺點(diǎn)，串-并混聯(lián)式機(jī)床應(yīng)運(yùn)而生。</p><p>　　混聯(lián)機(jī)床幾乎繼承了并聯(lián)機(jī)床的全部?jī)?yōu)點(diǎn)，同時(shí)其工作空間增大，運(yùn)動(dòng)學(xué)正解的求解困難程度及控制復(fù)雜程度均明顯降低。盡管其剛度和運(yùn)動(dòng)學(xué)精度

13、仍不如串聯(lián)機(jī)床高，但已顯示出強(qiáng)大的生命力。目前，商品化的并聯(lián)機(jī)床已投入使用。</p><p>　　課題組通過(guò)多年的研究發(fā)現(xiàn)，研拋屬于彈性加工，研拋過(guò)程中作用反力較小，因而對(duì)機(jī)床的剛度要求較低，同時(shí)，研拋機(jī)床需要在其終端執(zhí)行器上安裝位移-力柔順控制器，柔順控制器的安裝使研拋加工對(duì)機(jī)床運(yùn)動(dòng)精度的要求被弱化。研拋加工所具有的這些工藝特性，使得串-并混聯(lián)機(jī)床揚(yáng)長(zhǎng)避短，可以在研拋加工中得到較好的應(yīng)用。</p>

14、<p>　　基于對(duì)吉林省科技發(fā)展重點(diǎn)規(guī)劃課題“精密自動(dòng)研拋加工模具自由曲面的虛擬軸專用機(jī)床”的研究（機(jī)床照片見(jiàn)圖 1），本文就串-并混聯(lián)研拋機(jī)床的概念設(shè)計(jì)、運(yùn)動(dòng)學(xué)分析、插補(bǔ)控制、研拋實(shí)驗(yàn)等問(wèn)題展開(kāi)研究。</p><p>　　對(duì)串聯(lián)構(gòu)型、并聯(lián)構(gòu)型、混聯(lián)構(gòu)型機(jī)床的結(jié)構(gòu)特性、運(yùn)動(dòng)特性、控制特性等內(nèi)容進(jìn)行了分析比較，選定在并聯(lián) 3 自由度平動(dòng)平臺(tái)上串聯(lián) 2 回轉(zhuǎn)自由度的串-并混聯(lián)形式作為自由曲面研拋機(jī)床的構(gòu)型

15、。機(jī)床結(jié)構(gòu)見(jiàn)圖 2。</p><p>　　對(duì) 3 自由度平動(dòng)平臺(tái)的支鏈結(jié)構(gòu)形式進(jìn)行了分析。通過(guò)齊次坐標(biāo)變換方法，從支鏈平臺(tái)結(jié)構(gòu)位姿變換及其空間幾何關(guān)系分析入手，建立了三支鏈并聯(lián)平臺(tái)的封閉位置關(guān)系，得出了以虎克鉸為聯(lián)接關(guān)節(jié)條件下 3 自由度平動(dòng)平臺(tái)的最簡(jiǎn)單構(gòu)型形式和平臺(tái)工作空間與平臺(tái)機(jī)構(gòu)體積比值最大條件下的結(jié)構(gòu)參數(shù)配置。</p><p>　　基于并聯(lián)平臺(tái)封閉位置關(guān)系，給出了機(jī)床的運(yùn)動(dòng)學(xué)正解，

16、并對(duì)機(jī)床工作空間的形狀、構(gòu)成進(jìn)行了剖析。本文所述構(gòu)型形式的研拋機(jī)床具有由三段圓弧面構(gòu)成的柱形工作空間，工作空間的上頂和下底均為由四個(gè)球弧面構(gòu)成的復(fù)合曲面。首次將工具靈活性的概念引入機(jī)床的工作空間分析，并按照研拋工具所具有的靈活程度，將機(jī)床工作空間劃分為完全靈活工作空間、大部分靈活工作空間、小部分靈活工作空間和不靈活工作空間四個(gè)子區(qū)。通過(guò)推理，得出了機(jī)床完全靈活工作空間的主要影響因素是研拋工具桿長(zhǎng)度的結(jié)論。機(jī)床工作空間形式及構(gòu)成見(jiàn)圖 3。

17、</p><p>　　基于并聯(lián)平臺(tái)封閉位置關(guān)系和研拋工具的位置-姿態(tài)要求，對(duì)機(jī)床運(yùn)動(dòng)學(xué)逆解的構(gòu)成及求解方法進(jìn)行了研究。由于研拋?zhàn)藨B(tài)角δ1的存在，工具桿軸線可以形成一個(gè)以δ1為半角的姿態(tài)圓錐，致使機(jī)床的運(yùn)動(dòng)學(xué)逆解具有多值、不確定性。為使機(jī)床的運(yùn)動(dòng)學(xué)逆解合理、唯一，需添加工藝和運(yùn)動(dòng)限定條件。本文對(duì)研拋正壓力與研拋?zhàn)藨B(tài)角之間的關(guān)系、研拋線速度與研拋?zhàn)藨B(tài)角之間的關(guān)系進(jìn)行了分析，提出了滿足研拋正壓力和研拋線速度雙重控制要求

18、的δ1選擇工藝限定條件，并基于對(duì)加工效率、運(yùn)動(dòng)干涉等問(wèn)題的考慮，提出了限定姿態(tài)圓錐使用范圍的運(yùn)動(dòng)條件。綜合考慮，提出了研拋工具姿態(tài)的選擇控制策略，同時(shí)給出了機(jī)床各種靈活程度工作空間內(nèi)運(yùn)動(dòng)學(xué)逆解的求解方法。姿態(tài)圓錐及其可選用的范圍見(jiàn)圖4 和圖 5。</p><p>　　對(duì)離線插補(bǔ)和在線插補(bǔ)的工藝特性進(jìn)行了分析比較，結(jié)合目前插補(bǔ)控制的發(fā)展趨勢(shì)，選擇在線的直接插補(bǔ)作為新開(kāi)發(fā)數(shù)控系統(tǒng)的插補(bǔ)控制方式。并結(jié)合 NURBS 曲

19、面的參變量定義域特性，給出了 NURBS 曲面研拋的路徑規(guī)劃方式。</p><p>　　對(duì)研拋軌線行間距與表面許用殘留高度誤差、研拋工具半徑、曲面曲率半徑之間的關(guān)系（圖 6），插補(bǔ)步長(zhǎng)與表面加工誤差、研拋工具半徑、曲面曲率半徑之間的關(guān)系（圖 7）行了較為深入的分析，找出了兩類加工誤差的主要影響因素，并據(jù)此提出了針對(duì)粗研磨和精整拋光的研拋軌線行間距、插補(bǔ)步長(zhǎng)確定方法。</p><p>　　五

20、坐標(biāo)虛擬軸研拋機(jī)床數(shù)控系統(tǒng)的研究</p><p><b>　　一、說(shuō)明</b></p><p>　　我國(guó)于 2001 年正式加入 WTO 以來(lái)，經(jīng)濟(jì)發(fā)展迅速。隨著汽車、航空航天以及一批高新技術(shù)產(chǎn)業(yè)的發(fā)展，含有自由曲面的零件所占的比例越來(lái)越大，對(duì)自由曲面的加工質(zhì)量和效率要求也越來(lái)越高。但是目前對(duì)自由曲面的精加工主要還依靠熟練工人的手工操作。由于手工操作生產(chǎn)效益低下，加工

21、質(zhì)量不穩(wěn)定，難以適應(yīng)自由曲面低成本、短周期、高質(zhì)量的要求，研究一種高效自動(dòng)化的研拋設(shè)備勢(shì)在必行。本文針對(duì)用于自由曲面研拋加工的 JDYP51 型五坐標(biāo)虛擬軸研拋機(jī)床，研究出了一種基于 PMAC 的開(kāi)放式數(shù)控系統(tǒng)。</p><p>　　二、虛擬軸機(jī)床機(jī)構(gòu)設(shè)計(jì)的分析</p><p>　　本課題所研究的是并聯(lián)、串聯(lián)組合在一起的混聯(lián)機(jī)床，該機(jī)床為 3+2 式虛擬軸機(jī)床，即 3 個(gè)并聯(lián)軸實(shí)現(xiàn) X、Y

22、、Z 向 3 個(gè)坐標(biāo)運(yùn)動(dòng)，并聯(lián)機(jī)構(gòu)帶動(dòng)動(dòng)平臺(tái)實(shí)現(xiàn)平動(dòng)，在動(dòng)平臺(tái)上安裝 2 自由度串聯(lián)機(jī)器手，串聯(lián)機(jī)構(gòu)下加裝主軸裝置。用此機(jī)床進(jìn)行模具自由曲面的研拋加工。機(jī)床照片如圖 1 所示，</p><p>　　虛擬軸機(jī)床的總體結(jié)構(gòu)如圖 2 所示，它的并聯(lián)機(jī)構(gòu)由靜平臺(tái)、動(dòng)平臺(tái)和三個(gè)導(dǎo)軌立柱—滑塊—支鏈相結(jié)合的機(jī)構(gòu)組成 ，支鏈采用定長(zhǎng)桿，各桿件一端與滑塊，另一端與動(dòng)平臺(tái)用虎克鉸連接，滑塊由伺服電機(jī)和滾珠絲杠螺母副驅(qū)動(dòng)，沿導(dǎo)軌作上

23、下移動(dòng)。機(jī)床的串聯(lián)機(jī)構(gòu)連接在動(dòng)平臺(tái)上，由兩個(gè)轉(zhuǎn)動(dòng)關(guān)節(jié)構(gòu)成，分別繞軸轉(zhuǎn)動(dòng)來(lái)調(diào)整研拋工具的位姿。</p><p>　　以上所述即為并聯(lián)機(jī)構(gòu)的位置關(guān)系，同時(shí)可以利用齊次變換的方法建立機(jī)床串聯(lián)機(jī)構(gòu)的位置方程，并將串并聯(lián)機(jī)構(gòu)通過(guò)動(dòng)平臺(tái)為紐帶，得到機(jī)床整體的位置關(guān)系。</p><p>　　三、開(kāi)放式數(shù)控系統(tǒng)的硬件設(shè)計(jì)與實(shí)現(xiàn)</p><p>　　我們通過(guò)對(duì) JDYP51 型虛擬軸

24、研拋機(jī)床的研究，設(shè)計(jì)使用了一種基于PMAC 的開(kāi)放式數(shù)控系統(tǒng)。根據(jù)此數(shù)控系統(tǒng)所設(shè)計(jì)的數(shù)控裝置目前已經(jīng)完成，如圖 4 所示，控制裝置區(qū)域劃分由上至下為：實(shí)時(shí)顯示區(qū)，飼服控制區(qū)，控制電路區(qū)，核心控制區(qū)和主軸控制區(qū)。</p><p>　　制機(jī)、PMAC 運(yùn)動(dòng)控制器、雙端口 RAM（DPRAM）、伺服單元及交流伺服電機(jī)等組成。圖中的虛線將上位機(jī)和下位機(jī)的功能模塊分開(kāi)，實(shí)線框以外部分為系統(tǒng)的外部設(shè)備。由框圖可以看出，PMA

25、C 控制器與主機(jī)（IPC）之間的通訊采用了兩種方式。一種是總線通訊方式，另一種是利用 DPRAM 進(jìn)行數(shù)據(jù)通信，主機(jī)與 PMAC 運(yùn)動(dòng)控制器主要通過(guò) ISA 總線通訊，至于控制器和電機(jī)的狀態(tài)、所處的位置、速度、跟隨誤差等數(shù)據(jù)則通過(guò) DPRAM 交換信息。</p><p>　　圖4 JDYP51 NC 裝置</p><p>　　四、開(kāi)放式數(shù)控系統(tǒng)的軟件研究</p><p&

26、gt;　　虛擬軸機(jī)床數(shù)控系統(tǒng)實(shí)現(xiàn)正常工作，需要三個(gè)部分的系統(tǒng)軟件來(lái)執(zhí)行：IPC的用戶界面應(yīng)用程序；IPC 與 PMAC 上下位機(jī)間的通訊程序；PMAC 中對(duì)各種輸入、輸出量進(jìn)行監(jiān)控的 PLC 程序。其中通訊程序的開(kāi)發(fā)工作量最大、最困難、也最具有技巧性，Delta Tau 公司提供的 Pcomm32 已經(jīng)對(duì)通訊程序進(jìn)行了充分的開(kāi)發(fā)，我們可以通過(guò) Pmac.dll 進(jìn)一步利用。人機(jī)界面應(yīng)用程序采用Visual C++6.0 語(yǔ)言進(jìn)行開(kāi)發(fā)。P

27、LC 程序采用 Delta Tau 公司提供的語(yǔ)言進(jìn)行設(shè)計(jì)開(kāi)發(fā)。系統(tǒng)軟件工作機(jī)理如圖 6 所示，</p><p><b>　　五、結(jié)論</b></p><p>　　本課題對(duì) JDYP51 型五坐標(biāo)虛擬軸研拋機(jī)床的數(shù)控系統(tǒng)進(jìn)行了研究和設(shè)計(jì)，建立了一種基于 PMAC 和 IPC 的雙 CPU 開(kāi)放式數(shù)控系統(tǒng)，完成了機(jī)床的數(shù)控裝置，并通過(guò)此數(shù)控裝置對(duì)機(jī)床進(jìn)行了初步的調(diào)試和試

28、運(yùn)行，實(shí)現(xiàn)了基本的運(yùn)行要求。本論文主要的研究工作及研究成果如下：</p><p>　　1．對(duì)虛擬軸機(jī)床機(jī)構(gòu)整體設(shè)計(jì)和工作原理進(jìn)行了分析研究，通過(guò)分別對(duì)機(jī)床并聯(lián)機(jī)構(gòu)、串聯(lián)機(jī)構(gòu)和主軸研頭的位置解析，得到機(jī)床輸入與輸出的位置正逆解關(guān)系式，為數(shù)控系統(tǒng)對(duì)機(jī)床的軌跡運(yùn)動(dòng)控制提供了基礎(chǔ)。</p><p>　　2．對(duì)可編程多軸運(yùn)動(dòng)控制器(PMAC)進(jìn)行了深入系統(tǒng)的研究，針對(duì)本虛擬軸機(jī)床設(shè)計(jì)開(kāi)發(fā)了一種基于

29、PMAC 和 IPC 的雙 CPU 開(kāi)放式數(shù)控系統(tǒng)硬件結(jié)構(gòu)，根據(jù)硬件設(shè)計(jì)要求選擇了相應(yīng)的硬件設(shè)施和電子器件，組建完成了數(shù)控系統(tǒng)的控制裝置。</p><p>　　3．對(duì) CNC 系統(tǒng)軟件結(jié)構(gòu)與功能做了深入的研究，建立了數(shù)控系統(tǒng)軟件結(jié)構(gòu)框架。根據(jù)數(shù)控系統(tǒng)硬件的結(jié)構(gòu)設(shè)計(jì)，提出了系統(tǒng)軟件工作機(jī)理，同時(shí)參與了人機(jī)控制界面的開(kāi)發(fā)并對(duì)系統(tǒng)軟件設(shè)計(jì)做了進(jìn)一步的研究。此控制界面軟件實(shí)現(xiàn)了部分的硬件軟件化，將部分控制按鈕和指示燈等硬

30、設(shè)施轉(zhuǎn)化為軟件控制，同時(shí)可以根據(jù)需要添加多個(gè) I/O 通道，具有良好的開(kāi)放性和實(shí)時(shí)性。</p><p>　　4．通過(guò)數(shù)控系統(tǒng)的控制裝置對(duì) JDYP51 型五坐標(biāo)虛擬軸研拋機(jī)床進(jìn)行了調(diào)試，并在調(diào)試過(guò)程中完成了數(shù)控系統(tǒng)的參數(shù)設(shè)置與調(diào)整，初步完成了機(jī)床的合理運(yùn)行。通過(guò)對(duì)飼服系統(tǒng)的 PID 調(diào)節(jié)及位置速度反饋的分析結(jié)果，實(shí)現(xiàn)了較為理想的運(yùn)動(dòng)狀態(tài)。</p><p>　　Polishing Machi

31、ne Development</p><p>　　Yudy and development on hybrid virtual axis machine tool forpolishing free-form surfaces</p><p>　　1 Introduction</p><p>　　With the development of automobile

32、industry,electric industry and some new high-techindustries ,the larger is the proportion of NC machining parts with free-form surface in all, thehigher and higher requirements are made for quality and efficiency of mach

33、ining on free-formsurfaces. After the roughing method is used, precision machining, such as polishing and polishing,is necessary to obtain required workpiece surfaces. Near for over ten years, With the developmentat a hi

34、gh speed in relevant scie</p><p>　　2 Work principle and degree of freedom study on hybrid virtual axis machine tools for polishing </p><p>　　The sliding block that was drived by servo electromot

35、or and rolling screw thread-nut move up and down along with rail. The inseries mechanism of the machine tool was linked with move platform. It was made up of two rotation joints. The pose of polishing tools was adjusted

36、around axis. The structure principle of the machine tool is shown as Figure.1.</p><p>　　3.Position and pose analysis of series-parallet virtual axis machine tool for polishing free-form surface.</p>&

37、lt;p><b>　　Fig2</b></p><p>　　Model of parallel mechanism was established by ADAMS software, It is analyzed out that the parallel mechanism has three DOF and the motion status of move platform

38、is linear motion. it is shown As Fig2</p><p>　　Positive position solution of inseries mechanism of machine tools for polishing free-form surfaces was established through homogeneous transformation of the coo

39、rdinate frames. Inseries and parallel mechanism were regarded moving the platform as the tie, so positive position solution of machine tools was got. Axes position of polishing tools is related to inseries mechanism but

40、not parallel mechanism. It was proved by Euler angles.</p><p>　　4 kinetics analysis and simulation of series-parallel virtual axis machine tools for polishing free-form surfaces</p><p>　　Kinetic

41、s analysis of machine tools included inertia force calculate, force analysis, balance of motive force, establishment of kinetics model, dynamic simulation with computer,etc. In the case of increasing velocity of machine

42、tools, the importance of kinetics questions become particularly outstanding. Because of the uninterrupted development of computer, the methods of kinetics calculate and analysis and simulation become modernization. With

43、the deep study of kinetics, the velocity of machine t</p><p>　　5.Stand on structure of series-parallet virtual axis machine tool for polishing free-form surface.</p><p>　　The front view and bott

44、ommove platform and end effector,view of the polishing machineetc. Second, there are study andtool for free-form surfaces manufacture of control circuitand so on. There are three perfor-mance indexes :symmetry.worksp-ac

45、e.isotropy. On the basisof these, series-parallel machine tools were designed. Overall appearance of machine tools must be aesthetic. There are another requirements with good igidity and stability and enough operation sp

46、ace. Front view and bottom view of ma</p><p>　　6 conclusion</p><p>　　1. Five coordinates axes move together throng three parallel axes and two inseries axes. The position of polishing tools was

47、controlled by parallel mechanism and the pose was controlled by parallel mechanism. Thus, the work space for polishing was increased effectually.</p><p>　　2.3PTT parallel mechanism structure model of Adams w

48、as established. The problem of degree of freedom was studied. The simulation shows: 3PTT parallel mechanism move linearly.</p><p>　　3.Analytics methods were applied to deduct the positive position solution o

49、f machine tool’sparallel. Positive position solution was obtained by making use of homogeneous transformation of the coordinate frames. Axes pose of polishing tools was expressed by Euler angle. It is shown that the axes

50、 pose is related to inseries mechanism,but not parallel mechanism.</p><p>　　4.On the basis of influence coefficient theory and Lagrangian equation, it was deducted that the kinetic equation of inseries and p

51、arallel mechanism. Kinetic simulation model was established by Adams. The simulation shows: there are much difference of velocity and acceleration in X,Y, Z direction of the machine tool.. If it is required that high vel

52、ocity and acceleration in Z direction, the same direction forces were added to the three siding blocks. The difference of value should be small enoug</p><p>　　5.Through studying the structure and kinematics

53、and kinetic of the inseries-parallel virtual axis machine tool for polishing free-form surfaces and on the working foundation of polishing theory of forefathers, it was developed that the sample of inseries-parallel virt

54、ual axis machine tool for polishing free-form surfaces.</p><p>　　Keywords: parallel mechanism helix theory degree of freedom</p><p>　　influence coefficient free-form surfaces polishing&l

55、t;/p><p>　　virtual axis machine tool</p><p>　　Study on the Kinematics and Interpolation Control of the Series-Parallel Hybrid Polishing Machine Tool</p><p>　　In 1994 on the Chicago int

56、ernational exhibition of machine tool (IMTS’94), the parallel machine tools of Hexapod and Variax are displayed by the Ingersoll and Giddings & Lewis company of America for the first time, and it is paid close attent

57、ion by the whole world. Based on the three dimensional parallel mechanism, the parallel machine tool founds a new principle of the construction and the kinematics for the machine tool, and is known as " the biggest

58、transformation and innovation of the mechan</p><p>　　Compared with the traditional series machine tool, the parallel machine tool has many merits on the aspect of the structure and the kinematics characteris

59、tic such as higher proportion of the rigidity and weight, less quality of the moving parts, rapider respond speed, less error accumulation, easier realization for 6 axles uniting to move, easier calculation for inverse k

60、inematics result that is expedient for real time control, simpler structure of machine tool, higher technical additional value</p><p>　　The series-parallel hybrid machine tool has inherited all advantages of

61、 the parallel virtual axis machine tool nearly, and its workspace to be increased, the difficulty to calculate the forward kinematics result and to control the machine tool to be reduced. For these reasons, theer rigidit

62、y and movement precision of the machine tool. series-parallel hybrid machine tool has shown powerful vitality though its rigidity and movement precision is still lower than the series machine tool. Observing t</p>

63、<p>　　Studying the polishing for many years, the group knows that the polishing machining belongs to flexible machining. In the polishing process, the requirements for the rigidity and the movement precision of the

64、 machine tool are both lower because the active force of the polishing process is smaller and the displacement-force obedience controller is installed in the bearing rod of the polishing tool. For these reasons, the seri

65、es-parallel hybrid machine tool can be used as a better polishing machin</p><p>　　Based on the polishing machine tool made by the group, these questions such as the conception design, the kinematics analysis

66、, the interpolation control and the polishing experiment of the series-parallel hybrid polishing machine tool have been discussed deeply in the paper. Fig. 1 is the photo of the machine tool.</p><p>　　After

67、analyzing the structure characteristic, the kinematics characteristic and the control characteristic among the series conformation, the parallel conformation and the series-parallel conformation, select the conformation

68、connected 2 series rotation mechanisms on the 3 DOFS translation moving platform as the conformation of the polishing machine tool. Fig. 2 is the mechanisms of the machine tool.</p><p>　　The chain structure

69、of 3 DOFS translation platform is analyzed. Through the method ofhomogeneous transformation and the analysis of dimensional geometry connection about the position-posture of the parallel platform, the closed position con

70、nection of the parallel platform is given out, and based on it, the conclusion is revealed that the most simple mechanism of the 3 DOFS translation platform is 3 single-link chains mechanism which is symmetrical in space

71、 and jointed by Hook joints. The structu</p><p>　　Based on the closed position connection of the parallel platform, the forward kinematics result of the machine tool is given out, and the workspace of the ma

72、chine tool is discussed in form and shape. The workspace of the series-parallel hybrid virtual axis polishing machine tool is a column space that is made up of 3 circular-arc surfaces, and its top and bottom are both the

73、 complex curved surface consists of 4 ball-arc surfaces. The concept of tool flexibility was introduced firstly in the anal</p><p>　　Based on the closed position connection of the parallel platform and the r

74、equirement of position-posture on polishing tool, the inverse kinematics result of the machine tool is analyzed in form and calculating method. Being the polishing posture angle δ1, the axes of the polishing tool bearing

75、 rod can form a cone with half-angle δ1(shown as Fig. 4). That makes the inverse kinematics result of the machine tool have the characteristic of more values and uncertainty. In order to make the inverse ki</p>&l

76、t;p>　　According to the property of the variable definition region of the NURBS curved surface, the polishing path has been planned. For the reason of its excellent property, online direct interpolation control is chos

77、en as the interpolation control method of the new developing system.</p><p>　　Based on the analysis about the row space of the polishing trace and its influence factor, the interpolation step size and its in

78、fluence factor, the methods how to determine the row space of the polishing trace and the interpolation step size are given out. The relation between row space and radius of the curved surface is shown in Fig. 6, and the

79、 relation between interpolation step size and radius of the curved surface is shown in Fig. 7.</p><p>　　Research on CNC System of five-coordinate Virtual Axis polishing Machine Tool</p><p>　　1．I

80、ntroduction</p><p>　　Since our country was affiliated to WTO in due form in 2001, the economic development is speedier. With the development of automobile industry, aeronautics and astronautics industry and

81、some new high-tech industries, the larger is the proportion of NC machining parts with free-form surface in all, the higher and higher requirements are made for quality and efficiency of machining on free-form surfaces.

82、However, these subsequent processes of precision machining still depend</p><p>　　mainly on the handwork of skilled mechanists presently. Productivity effect of handwork is very low and its quality is unstabl

83、e. As to the machining of free-form surfaces, low cost and short period and high quality were its main aim. As a result of that, the research of a kind of increasingly automated polishing equipment is imperative. This pa

84、per regards the JDYP51 model five-coordinate virtual axis polishing machine tool for polishing free-form surfaces. We have researched a kind of open archi</p><p>　　2．Mechanism design analysis of virtual axis

85、 machine tool</p><p>　　The series-parallel machine tool, which is well arranged by in series and parallel, is researched in this dissertation.It is a “3+2” model virtual axis machine tool .Three parallel axi

86、s carry out there movements in Xcoordinates、Ycoordinates and Z coordinates. Parallel mechanism drives move platform to move flatly. In series mechanism which have two degree of freedoms is fixed in move platform. princip

87、al axis mechanism is fixed with In series mechanism. The machine tool can be used to polish free</p><p>　　The whole structure of virtual axis machine tool is shown as Figure2. The parallel mechanism are comp

88、osed of still platform, move platform, three poles and a chain that is fix long pole. At one end of every pole, a sliding block is linked. At the other end of it, the move platform is linked by Huke joint. The sliding bl

89、ock that is drived by servo electromotor and rolling screw thread-nut move up and down along with rail. The inseries mechanism of the machine tool is linked with move platform. It</p><p>　　through geometry r

90、elation, three kindsof relation between input and export of move platform are obtained.</p><p>　　These are position analysis of parallel mechanism.And Positive position solution of inseries mechanism of mach

91、ine tools is established through homogeneous transformation of the coordinate frames. Inseries and parallel mechanism are regarded moving the platform as the tie, so the position solution of machine tools can be got.<

92、/p><p>　　3. Design and realization of open NC system hardware </p><p>　　Through research on JDYP51 model five-coordinate virtual axis polishing machine tool, a kind of open NC system is designed on

93、 the basis of PMAC.NC equipment has been already manufactured, which is shown as figure 4. The control equipment was divided as: real time show area, servo control area, control circuit area, core control area and main s

94、pindle control area.</p><p>　　Function module of the machine upside and underside are divided by dashed shown as figure 5.The part outside solid line frame is the exterior system equipments. It is shown as f

95、rame diagram that there are two communication mode between PMAC and IPC. One is bus communication mode, the other is DPRAM data communication mode. The communication between IPC and PMAC is realized by ISA bus. The messa

96、ge between controller and the data of position and velocity and following error of electric engineering</p><p>　　4.Software research on open NC system</p><p>　　Three parts of system software are

97、 required to realize the normal work of the NC system of virtual axis polishing machine tool, which are user interface application program of IPC , communication program between IPC and PMAC upside and underside, PLC mon

98、itor program for input and output of PMAC. The development of communication program is utmost and difficult and full of technique. The Pcomm32 provided by Delta Tau company has made sufficient development of communicatio

99、n program. We can make fur</p><p>　　5、Conclusion</p><p>　　The subject is to research and design NC system of JDYP51 model five-coordinate virtual axis polishing machine tool, an open double CPU

100、NC system basing PMAC and IPC has built up and installed on the machine tool, moreover, the basic functions have been fulfilled by debugging and making experiments on the machine tool through the CNC system. The key rese