機(jī)械裝備的發(fā)展中英文翻譯、外文文獻(xiàn)翻譯、外文翻譯

PAGE機(jī)械裝備的發(fā)展一．機(jī)械裝備的應(yīng)用近十幾年來(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)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。二．狀態(tài)分析本處所開(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)。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)。三、自由曲面研拋機(jī)床的位姿分析根據(jù)該機(jī)車(chē)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)構(gòu)的解析圖形，如圖2所示。圖2研拋機(jī)床并聯(lián)機(jī)構(gòu)解析圖兩端取模平方知：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)。四、自由曲面研拋機(jī)床的動(dòng)力學(xué)分析及其仿真機(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)器的控制提供較為精確的理論基礎(chǔ)。五、自由曲面研拋機(jī)床結(jié)構(gòu)的研究機(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(chēng)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。圖3自由曲面研拋機(jī)床的主、俯視圖六、結(jié)論（1）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。（2）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。仿真結(jié)果表明：3PTT并聯(lián)機(jī)構(gòu)是平動(dòng)的機(jī)構(gòu)。（3）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)。（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。（5）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)。串-并混聯(lián)研拋機(jī)床運(yùn)動(dòng)與控制研究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)床結(jié)構(gòu)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。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)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。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。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。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(zhuān)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。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。機(jī)床結(jié)構(gòu)見(jiàn)圖2。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?；诓⒙?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，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?；诓⒙?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(mǎn)足研拋正壓力和研拋線速度雙重控制要求的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。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。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(lèi)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。五坐標(biāo)虛擬軸研拋機(jī)床數(shù)控系統(tǒng)的研究一、說(shuō)明我國(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(chē)、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)。二、虛擬軸機(jī)床機(jī)構(gòu)設(shè)計(jì)的分析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、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，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。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。三、開(kāi)放式數(shù)控系統(tǒng)的硬件設(shè)計(jì)與實(shí)現(xiàn)我們通過(guò)對(duì)JDYP51型虛擬軸研拋機(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)。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，PMAC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。圖4JDYP51NC裝置四、開(kāi)放式數(shù)控系統(tǒng)的軟件研究虛擬軸機(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(hù)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，DeltaTau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VisualC++6.0語(yǔ)言進(jìn)行開(kāi)發(fā)。PLC程序采用DeltaTau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，五、結(jié)論本課題對(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：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)。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。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。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)。PolishingMachineDevelopmentYudyanddevelopmentonhybridvirtualaxismachinetoolforpolishingfree-formsurfaces1IntroductionWiththedevelopmentofautomobileindustry,electricindustryandsomenewhigh-techindustries,thelargeristheproportionofNCmachiningpartswithfree-formsurfaceinall,thehigherandhigherrequirementsaremadeforqualityandefficiencyofmachiningonfree-formsurfaces.Aftertheroughingmethodisused,precisionmachining,suchaspolishingandpolishing,isnecessarytoobtainrequiredworkpiecesurfaces.Nearforovertenyears,Withthedevelopmentatahighspeedinrelevantscienceandtechnology,suchasthetechnologyofthecomputerandmoderncontroltheory,etc.,flexibilitymachiningbecomemoreperfect.Theautomaticmachiningoffree-formsurfacescometotruebasically.However,thesesubsequentprocessesofprecisionmachiningstilldependmainlyonthehandworkofskilledmechanists.Productivityeffectofhandworkisverylowanditsqualityisunstable.Astothemachiningoffree-formsurfaces,lowcostandshortperiodandhighqualitywereitsmainaim.Asaresultofthat,theresearchofakindofincreasinglyautomatedpolishingequipmentisimperative.Series-parallelvirtualaxismachinetoolsforpolishingfree-formsurfacesmeetstherequirement.2WorkprincipleanddegreeoffreedomstudyonhybridvirtualaxismachinetoolsforpolishingTheslidingblockthatwasdrivedbyservoelectromotorandrollingscrewthread-nutmoveupanddownalongwithrail.Theinseriesmechanismofthemachinetoolwaslinkedwithmoveplatform.Itwasmadeupoftworotationjoints.Theposeofpolishingtoolswasadjustedaroundaxis.ThestructureprincipleofthemachinetoolisshownasFigure.1.3.Positionandposeanalysisofseries-paralletvirtualaxismachinetoolforpolishingfree-formsurface.Fig2ModelofparallelmechanismwasestablishedbyADAMSsoftware,ItisanalyzedoutthattheparallelmechanismhasthreeDOFandthemotionstatusofmoveplatformislinearmotion.itisshownAsFig2Positivepositionsolutionofinseriesmechanismofmachinetoolsforpolishingfree-formsurfaceswasestablishedthroughhomogeneoustransformationofthecoordinateframes.Inseriesandparallelmechanismwereregardedmovingtheplatformasthetie,sopositivepositionsolutionofmachinetoolswasgot.Axespositionofpolishingtoolsisrelatedtoinseriesmechanismbutnotparallelmechanism.ItwasprovedbyEulerangles.4kineticsanalysisandsimulationofseries-parallelvirtualaxismachinetoolsforpolishingfree-formsurfacesKineticsanalysisofmachinetoolsincludedinertiaforcecalculate,forceanalysis,balanceofmotiveforce,establishmentofkineticsmodel,dynamicsimulationwithcomputer,etc.Inthecaseofincreasingvelocityofmachinetools,theimportanceofkineticsquestionsbecomeparticularlyoutstanding.Becauseoftheuninterrupteddevelopmentofcomputer,themethodsofkineticscalculateandanalysisandsimulationbecomemodernization.Withthedeepstudyofkinetics,thevelocityofmachinetoolswasfurtherimproved.Itofferstheorybasisforcontrolofthemachinetools.Themoveplatformcanonlyrealizelinearmotionin3Dspace.Thereisnotrotationkineticnergy.Thenthekineticenergyofmoveplatformisdesignofmachinetoolsshelfand.5.Standonstructureofseries-paralletvirtualaxismachinetoolforpolishingfree-formsurface.Thefrontviewandbottommoveplatformandendeffector,viewofthepolishingmachineetc.Second,therearestudyandtoolforfree-formsurfacesmanufactureofcontrolcircuitandsoon.Therearethreeperfor-manceindexes:symmetry.worksp-ace.isotropy.Onthebasisofthese,series-parallelmachinetoolsweredesigned.Overallappearanceofmachinetoolsmustbeaesthetic.Thereareanotherrequirementswithgoodigidityandstabilityandenoughoperationspace.Frontviewandbottomviewofmachinetoolsforpolishingfree-formsurfacesareshownasFigure.3.6conclusion1.Fivecoordinatesaxesmovetogetherthrongthreeparallelaxesandtwoinseriesaxes.Thepositionofpolishingtoolswascontrolledbyparallelmechanismandtheposewascontrolledbyparallelmechanism.Thus,theworkspaceforpolishingwasincreasedeffectually.2.3PTTparallelmechanismstructuremodelofAdamswasestablished.Theproblemofdegreeoffreedomwasstudied.Thesimulationshows:3PTTparallelmechanismmovelinearly.3.Analyticsmethodswereappliedtodeductthepositivepositionsolutionofmachinetool’sparallel.Positivepositionsolutionwasobtainedbymakinguseofhomogeneoustransformationofthecoordinateframes.AxesposeofpolishingtoolswasexpressedbyEulerangle.Itisshownthattheaxesposeisrelatedtoinseriesmechanism,butnotparallelmechanism.4.OnthebasisofinfluencecoefficienttheoryandLagrangianequation,itwasdeductedthatthekineticequationofinseriesandparallelmechanism.KineticsimulationmodelwasestablishedbyAdams.Thesimulationshows:therearemuchdifferenceofvelocityandaccelerationinX,Y,Zdirectionofthemachinetool..IfitisrequiredthathighvelocityandaccelerationinZdirection,thesamedirectionforceswereaddedtothethreesidingblocks.Thedifferenceofvalueshouldbesmallenough.Thedifferenceofforcevalueonthethreeslidingblocksshouldbebigenough,ifrequiringhighvelocityandaccelerationinX,Ydirection.5.Throughstudyingthestructureandkinematicsandkineticoftheinseries-parallelvirtualaxismachinetoolforpolishingfree-formsurfacesandontheworkingfoundationofpolishingtheoryofforefathers,itwasdevelopedthatthesampleofinseries-parallelvirtualaxismachinetoolforpolishingfree-formsurfaces.Keywords:parallelmechanismhelixtheorydegreeoffreedominfluencecoefficientfree-formsurfacespolishingvirtualaxismachinetoolStudyontheKinematicsandInterpolationControloftheSeries-ParallelHybridPolishingMachineToolIn1994ontheChicagointernationalexhibitionofmachinetool(IMTS’94),theparallelmachinetoolsofHexapodandVariaxaredisplayedbytheIngersollandGiddings&LewiscompanyofAmericaforthefirsttime,anditispaidcloseattentionbythewholeworld.Basedonthethreedimensionalparallelmechanism,theparallelmachinetoolfoundsanewprincipleoftheconstructionandthekinematicsforthemachinetool,andisknownas"thebiggesttransformationandinnovationofthemechanismformachinetoolinthiscentury","themachinetoolofthe21century".Inafteryears,themanufacturersofItaly,Japan,Russia,Norway,Switzerland,SwedenandDanishetc.developparallelmachinetoolcompetitively.Intheendof1997,thefirstparallelmachinetoolVAMT1YofourcountrywasdevelopedbytheTsinghuaUniversityandTianjinUniversityjointly.Comparedwiththetraditionalseriesmachinetool,theparallelmachinetoolhasmanymeritsontheaspectofthestructureandthekinematicscharacteristicsuchashigherproportionoftherigidityandweight,lessqualityofthemovingparts,rapiderrespondspeed,lesserroraccumulation,easierrealizationfor6axlesunitingtomove,easiercalculationforinversekinematicsresultthatisexpedientforrealtimecontrol,simplerstructureofmachinetool,highertechnicaladditionalvalueandsoon.However,theparallelmachinetoolhasalsothedisadvantagessuchassmallerworkspace,moredifficultcalculationforforwardkinematicsresult,deepernonlinearcouplingamongeachaxisandmorecomplexcontrolforinterpolation,moredifficultkinematicsmarking,weakItisagainsttheshortcomingsoftheparallelmachinetoolthatthehybridmachinetoolwithseries-parallelconformationhasbeendeveloped.Theseries-parallelhybridmachinetoolhasinheritedalladvantagesoftheparallelvirtualaxismachinetoolnearly,anditsworkspacetobeincreased,thedifficultytocalculatetheforwardkinematicsresultandtocontrolthemachinetooltobereduced.Forthesereasons,theerrigidityandmovementprecisionofthemachinetool.series-parallelhybridmachinetoolhasshownpowerfulvitalitythoughitsrigidityandmovementprecisionisstilllowerthantheseriesmachinetool.Observingtheconformationofthemachinetoolstobemaderecently,mostlyofthemareseries-parallelone.Studyingthepolishingformanyyears,thegroupknowsthatthepolishingmachiningbelongstoflexiblemachining.Inthepolishingprocess,therequirementsfortherigidityandthemovementprecisionofthemachinetoolarebothlowerbecausetheactiveforceofthepolishingprocessissmallerandthedisplacement-forceobediencecontrollerisinstalledinthebearingrodofthepolishingtool.Forthesereasons,theseries-parallelhybridmachinetoolcanbeusedasabetterpolishingmachinetool.Basedonthepolishingmachinetoolmadebythegroup,thesequestionssuchastheconceptiondesign,thekinematicsanalysis,theinterpolationcontrolandthepolishingexperimentoftheseries-parallelhybridpolishingmachinetoolhavebeendiscusseddeeplyinthepaper.Fig.1isthephotoofthemachinetool.Afteranalyzingthestructurecharacteristic,thekinematicscharacteristicandthecontrolcharacteristicamongtheseriesconformation,theparallelconformationandtheseries-parallelconformation,selecttheconformationconnected2seriesrotationmechanismsonthe3DOFStranslationmovingplatformastheconformationofthepolishingmachinetool.Fig.2isthemechanismsofthemachinetool.Thechainstructureof3DOFStranslationplatformisanalyzed.Throughthemethodofhomogeneoustransformationandtheanalysisofdimensionalgeometryconnectionabouttheposition-postureoftheparallelplatform,theclosedpositionconnectionoftheparallelplatformisgivenout,andbasedonit,theconclusionisrevealedthatthemostsimplemechanismofthe3DOFStranslationplatformis3single-linkchainsmechanismwhichissymmetricalinspaceandjointedbyHookjoints.Thestructureparametersarediscussedundertheconditionofthebiggestratiobetweentheworkspaceandthestructurespaceoftheplatform.Basedontheclosedpositionconnectionoftheparallelplatform,theforwardkinematicsresultofthemachinetoolisgivenout,andtheworkspaceofthemachinetoolisdiscussedinformandshape.Theworkspaceoftheseries-parallelhybridvirtualaxispolishingmachinetoolisacolumnspacethatismadeupof3circular-arcsurfaces,anditstopandbottomareboththecomplexcurvedsurfaceconsistsof4ball-arcsurfaces.Theconceptoftoolflexibilitywasintroducedfirstlyintheanalysisofmachinetoolworkspace,andaccordingtoit,theworkspaceofthemachinetoolisdividedintofourkindsofflexibleworkspace,thefullflexible-workspace,themostflexible-workspace,thefractionflexible-workspaceandunhandyworkspace.Themaininfluencefactoronthefullflexible-workspaceofthemachinetoolisthebearingrodlengthofthepolishingtool.TheworkspaceofthemachinetoolisshownasFig.3.Basedontheclosedpositionconnectionoftheparallelplatformandtherequirementofposition-postureonpolishingtool,theinversekinematicsresultofthemachinetoolisanalyzedinformandcalculatingmethod.Beingthepolishingpostureangleδ1,theaxesofthepolishingtoolbearingrodcanformaconewithhalf-angleδ1(shownasFig.4).Thatmakestheinversekinematicsresultofthemachinetoolhavethecharacteristicofmorevaluesanduncertainty.Inordertomaketheinversekinematicsresultuniquely,thetechnicalrestrictingconditionsandthemotionrestrictingconditionsshouldbeappended.Therelationsamongtheactiveforce,thepolishingvelocityandthepolishingpostureangleδ1areanalyzed,andthetechnicalrestrictingconditions,themotionrestrictingconditionsareputforward.Themethodofcalculatingthepolishingpostureinfourkindsofflexibleworkspaceisintroduced.Afterthat,theinversekinematicsresultofthemachinetoolisgivenout.Fig.5isthesemi-conethattheaxesofthepolishingtoolbearingrodshouldbelocatedon.AccordingtothepropertyofthevariabledefinitionregionoftheNURBScurvedsurface,thepolishingpathhasbeenplanned.Forthereasonofitsexcellentproperty,onlinedirectinterpolationcontrolischosenastheinterpolationcontrolmethodofthenewdevelopingsystem.Basedontheanalysisabouttherowspaceofthepolishingtraceanditsinfluencefactor,theinterpolationstepsizeanditsinfluencefactor,themethodshowtodeterminetherowspaceofthepolishingtraceandtheinterpolationstepsizearegivenout.TherelationbetweenrowspaceandradiusofthecurvedsurfaceisshowninFig.6,andtherelationbetweeninterpolationstepsizeandradiusofthecurvedsurfaceisshowninFig.7.ResearchonCNCSystemoffive-coordinateVirtualAxispolishingMachineTool1．IntroductionSinceourcountrywasaffiliatedtoWTOindueformin2001,theeconomicdevelopmentisspeedier.Withthedevelopmentofautomobileindustry,aeronauticsandastronauticsindustryandsomenewhigh-techindustries,thelargeristheproportionofNCmachiningpartswithfree-formsurfaceinall,thehigherandhigherrequirementsaremadeforqualityandefficiencyofmachiningonfree-formsurfaces.However,thesesubsequentprocessesofprecisionmachiningstilldependmainlyonthehandworkofskilledmechanistspresently.Productivityeffectofhandworkisverylowanditsqualityisunstable.Astothemachiningoffree-formsurfaces,lowcostandshortperiodandhighqualitywereitsmainaim.Asaresultofthat,theresearchofakindofincreasinglyautomatedpolishingequipmentisimperative.ThispaperregardstheJDYP51modelfive-coordinatevirtualaxispolishingmachinetoolforpolishingfree-formsurfaces.WehaveresearchedakindofopenarchitectureCNCsystemwhichisbasedonPMAC.2．MechanismdesignanalysisofvirtualaxismachinetoolTheseries-parallelmachinetool,whichiswellarrangedbyinseriesandparallel,isresearchedinthisdissertation.Itisa“3+2”modelvirtualaxismachinetool.ThreeparallelaxiscarryouttheremovementsinXcoordinates、YcoordinatesandZcoordinates.Parallelmechanismdrivesmoveplatformtomoveflatly.Inseriesmechanismwhichhavetwodegreeoffreedomsisfixedinmoveplatform.principalaxismechanismisfixedwithInseriesmechanism.Themachinetoolcanbeusedtopolishfree-formsurfacesofmold.thephotoofmachinetoolisshownasFigure1.ThewholestructureofvirtualaxismachinetoolisshownasFigure2.Theparallelmechanismarecomposedofstillplatform,moveplatform,threepolesandachainthatisfixlongpole.Atoneendofeverypole,aslidingblockislinked.Attheotherendofit,themoveplatformislinkedbyHukejoint.Theslidingblockthatisdrivedbyservoelectromotorandrollingscrewthread-nutmoveupanddownalongwithrail.Theinseriesmechanismofthemachinetoolislinkedwithmoveplatform.Itismadeupoftworotationjoints.Theposeofpolishingtoolsisadjustedaroundaxis.throughgeometryrelation,threekindsofrelationbetweeninputandexportofmoveplatformareobtained.Thesearepositionanalysisofparallelmechanism.AndPositivepositionsolutionofinseriesmechanismofmachinetoolsisestablishedthroughhomogeneoustransformationofthecoordinateframes.Inseriesandparallelmechanismareregardedmovingtheplatformasthetie,sothepositionsolutionofmachinetoolscanbegot.3.DesignandrealizationofopenNCsystemhardwareThroughresearchonJDYP51modelfive-coordinatevirtualaxispolishingmachinetool,akindofopenNCsystemisdesignedonthebasisofPMAC.NCequipmenthasbeenalreadymanufactured,whichisshownasfigure4.Thecontrolequipmentwasdividedas:realtimeshowarea,servocontrolarea,controlcircuitarea,corecontrolareaandmainspindlecontrolarea.Functionmoduleofthemachineupsideandundersidearedividedbydashedshownasfigure5.Thepartoutsidesolidlineframeistheexteriorsystemequipments.ItisshownasframediagramthattherearetwocommunicationmodebetweenPMACandIPC.Oneisbuscommunicationmode,theotherisDPRAMdatacommunicationmode.ThecommunicationbetweenIPCandPMACisrealizedbyISAbus.Themessagebetweencontrollerandthedataofpositionandvelocityandfollowingerrorofelectricengineeringexchanged.4.SoftwareresearchonopenNCsystemThreepartsofsystemsoftwarearerequiredtorealizethenormalworkoftheNCsystemofvirtualaxispolishingmachinetool,whichareuserinterfaceapplicationprogramofIPC,communicationprogrambetweenIPCandPMACupside