尾座體加工工藝及夾具設(shè)計

39頁 9900字?jǐn)?shù)+論文說明書+任務(wù)書+6張CAD圖紙【詳情如下】

任務(wù)書.doc

刨肖夾具裝配圖.dwg

外文翻譯--分布式機床的設(shè)計.doc

夾具零件圖.dwg

尾座體加工工藝及夾具設(shè)計論文.doc

尾座體零件圖.dwg

工序卡.doc

底面刨夾具夾具圖.dwg

機床尾座體的加工與設(shè)計開題報告.doc

14孔夾具裝配圖.dwg

17孔夾具裝配圖.dwg

摘 要

本課題主要是設(shè)計某機床尾座體的加工工藝及夾具的設(shè)計，在設(shè)計中采用先設(shè)計該尾座體的加工工藝在根據(jù)加工工藝來選取夾具的設(shè)計的方案和夾具的具體設(shè)計；而設(shè)計的重點是夾具的設(shè)計。由于工件的孔17和14都要以底面做為基準(zhǔn)加工，故首先得做出底面的加工夾具。由于孔17的精度要求高，和定位尺寸誤差小，為保證孔的位置和加工準(zhǔn)確性我們一定在加工底面的時間通過畫線找出底面的加工余量。這樣就可以更好的保證孔17的位置和加工精度！加工孔14的夾具其實就是在加工底面夾具的基礎(chǔ)上加了一個45度斜度板。加工孔17的時間為保證相對于A和B面的平行度我們就得要準(zhǔn)確的設(shè)計出以A和B面定為的夾具！還考慮到工件的圓度和圓柱度的誤差小，我們設(shè)計的夾具就具有對孔17的夾具定位準(zhǔn)確，和加工時間的震動小，那就得在孔17的附近找個定位加緊點！

關(guān)鍵詞  加工工藝，夾具，尾座體，設(shè)計

ABSTRACT

This topic is mainly design that designs the tail a body of some tool machine to process the craft and tongses, adopting to design first in the design a body of that tail processes the craft at according to process the craft to select by examinations the tongs of the project of the design and concrete design of the tongs;But the point of design is the design of the tongs.Because the bore of the work piece 17 and 14 all want to face to be used as the basis to process with the bottom, past have to do a bottom to face first of process the tongs.Because bore 17 of accuracy have high request, and position the size error margin small, for guarantee the position of the bore and process the accuracy we certainly at process the bottom to face of time pass to draw the line to find out the bottom to face of process the amount of remaining.Thus can with better assurance bore 17 of position and process the accuracy!Process the bore 14 of tongs was in processing the foundation that the bottom faces the furniture to add one 45 degrees of gradient plank in fact.Process the bore 17 of time is opposite for assurance to run parallel with B face of in the A we have to design accurately with the AN and B faces to settle for of tongs!Return in consideration of a degree of the work piece and the error margin of the cylinder degrees are small, the furniture that we design have to the bore 17 of tongs fixed position is accurate, and process the vibration of time small, that have to in the bore 17 of neighborhood seek a fixed position to step up the point!

Keyword  process the craft, tongs, a body of tail, design

目 錄

摘 要……………………………………………………………………Ⅰ

ABSTRACT………………………………………………………………Ⅱ

1緒論……………………………………………………………………1

2零件分析  ……………………………………………………………2

2.1零件的特點……………………………………………………………2

2.2工藝分析………………………………………………………………2

3工藝規(guī)程設(shè)計…………………………………………………………4

3.1確定毛坯的制造形成……………………………………………………4

3.2基面的選擇……………………………………………………………4

3.3制定工藝路線…………………………………………………………4

3.4機械加工余量、工序尺寸及毛坯的確定……………………………8

3.5確定切削用量及基本工時………………………………………………12

4夾具設(shè)計 ……………………………………………………………28

4.1問題的提出…………………………………………………………28

4.2夾具設(shè)計 …………………………………………………………28

總結(jié) ……………………………………………………………………33

參考書目 ………………………………………………………………34

致謝 ……………………………………………………………………35

1 緒 論

機械設(shè)計制造及其夾具設(shè)計是對我們完成大學(xué)四年的學(xué)習(xí)內(nèi)容后進(jìn)行的總體的系統(tǒng)的復(fù)習(xí)，融會貫通四年所學(xué)的知識，將理論與實踐相結(jié)合。在畢業(yè)前進(jìn)行的一次模擬訓(xùn)練，為我們即將走向自己的工作崗位打下良好的基礎(chǔ)。

機械加工工業(yè)規(guī)程是指導(dǎo)生產(chǎn)的重要的技術(shù)性文件，它直接關(guān)系到產(chǎn)品的質(zhì)量、生產(chǎn)率及其加工產(chǎn)品的經(jīng)濟效益，因此工藝規(guī)程的編制的好壞是生產(chǎn)該產(chǎn)品的質(zhì)量的重要保證的重要依據(jù)。在編制工藝時須保證其合理性、科學(xué)性、完善性。

夾具設(shè)計是為了保證產(chǎn)品的質(zhì)量的同時提高生產(chǎn)的效率、改善工人的勞動強度、降低生產(chǎn)成本，因此在大批量生產(chǎn)中，常采用專用夾具

這次畢業(yè)設(shè)計，難免會有許多的問題，懇請各位指導(dǎo)教師給予幫助，希望通過這次設(shè)計能鍛煉自己的分析問題、解決問題的能力，為以后 參加工作打下良好的基礎(chǔ)。

2 零件分析

題目所給的零件是機床尾座體，尾座安裝在機床的右端導(dǎo)軌上，尾座上的套筒可以安裝頂尖，以支承較長的工件的右端（即頂持工件的中心孔）、安裝鉆頭、絞刀，進(jìn)行孔加工，也可以安裝絲錐攻螺紋工具、圓析牙套螺紋工具加工內(nèi)、外螺紋。尾座可以沿尾座導(dǎo)軌作縱向調(diào)整移動，然后壓下尾座緊固手輪將尾座夾緊在所需位置，搖動尾座手輪可以實現(xiàn)對工件的頂緊、松開或?qū)ぜM(jìn)行切削的縱向進(jìn)給

2.1 零件的特點

由圖可知，該零件為不太規(guī)則的部件，其主要技術(shù)特點如下：

1.鑄件需要消除毛刺和砂粒、并作退火處理

2.  17H6要求圓度為0.003

3.  17H6要求圓柱度0.004

4.  17H6與導(dǎo)軌面的平行度為0.005

5.  17H6與燕尾面的平行度為0.005

6.  17H6的孔軸心線與導(dǎo)軌面的位置度誤差為0～0.1

7.  17H6的孔與燕尾面的位置度誤差不超過0.15

8.各面的粗糙度達(dá)到需要的要求

9.  17H6的孔需精加工、研配

10.導(dǎo)軌面配刮10～13點/25 25

2.2 零件工藝分析

根據(jù)零件圖可知、主要進(jìn)行導(dǎo)軌面的加工、孔加工和表面加工、鉆孔、攻絲，孔的精度要求高。該零件年生產(chǎn)5000件屬大批量生產(chǎn)，在加工是為了提高勞動效率、降低成本，設(shè)計加工零件需要設(shè)計專用夾具。

（3）定位誤差

①定位元件尺寸及公差的確定。夾具的主要定位是導(dǎo)軌面和燕尾，該端面與孔的垂直度有一定的要求。

②還有就是45 的夾角可能存在一定的誤差。

5 總 結(jié)

通過這次畢業(yè)設(shè)計，使我對產(chǎn)品設(shè)計過程有了進(jìn)一步的認(rèn)識，對結(jié)構(gòu)設(shè)計有了更進(jìn)一步的了解，也加深了對大學(xué)四年中所學(xué)的基礎(chǔ)知識的學(xué)習(xí)和理解。畢業(yè)設(shè)計是理論聯(lián)系實際的最有效方法。在具體設(shè)計過程中，必須考慮到方方面面的問題，在理論上正確無誤的設(shè)計，在實際中往往存在各種問題。這樣，在設(shè)計時就必須考慮，所設(shè)計的機構(gòu)是否合理在實際運用中能否正常工作。畢業(yè)設(shè)計使我學(xué)會了從實際出發(fā)設(shè)計產(chǎn)品，而不僅僅考慮理論上的可行性。

在本次課程設(shè)計的制作過程中，我深深的體會到一個看似簡單的機構(gòu)其實并不像我們想象中的那么簡單，它所要考慮的東西還很多。要完善一個產(chǎn)品首先應(yīng)該對其功能作用有充分的了解，然后對實現(xiàn)這些功能的結(jié)構(gòu)進(jìn)行分析，考慮哪種結(jié)構(gòu)能夠?qū)崿F(xiàn)這種功能，哪種結(jié)構(gòu)更加合理、有效、簡便。根據(jù)了解的類似結(jié)構(gòu)進(jìn)行仔細(xì)分析，再進(jìn)行適當(dāng)?shù)母倪M(jìn)、創(chuàng)新，爭取用最低的成本實現(xiàn)最先進(jìn)的功能。最后再根據(jù)結(jié)構(gòu)設(shè)計出各個零件，應(yīng)當(dāng)考慮到零件的加工、材料、成本等問題。

在設(shè)計過程中，盧宗彪老師給予了我悉心指導(dǎo)，提出好的建議，使我獲益良多。同學(xué)之間互相研討，共同解決問題，互相幫助，互相學(xué)習(xí)，使我體會到了團(tuán)隊的可貴，懂得了團(tuán)隊精神的重要性。 畢業(yè)設(shè)計是我在學(xué)校的最后一次答卷，我也把它看成是我邁向社會的第一步

參 考 文 獻(xiàn)

[1] 東北重型機械學(xué)院，洛陽農(nóng)業(yè)機械學(xué)院，長春汽車廠工人大學(xué)。機床夾具設(shè)計手冊［Ｍ］。上?？茖W(xué)技術(shù)出版社，1984。

[2] 李洪。機械加工工藝手冊［Ｍ］。北京出版社，1996。

[3] 李慶壽。機床夾具設(shè)計［Ｍ］。機械工業(yè)出版社，1991。

[4] 張進(jìn)生。機械制造工藝與夾具設(shè)計指導(dǎo)［Ｍ］。機械工業(yè)出版社，1995。

[5] 上海市金屬切削技術(shù)協(xié)會。金屬切削手冊［Ｍ］。上海科學(xué)技術(shù)出版社，2004。

[6] 黃如林，劉新佳，汪群。切削加工簡明實用手冊［Ｍ］?；瘜W(xué)工業(yè)出版社，2004。

[7] 王光斗，王春福。機床夾具設(shè)計手冊［Ｍ］。上海科學(xué)技術(shù)出版社，2002。

[8] [ 周永強，高等學(xué)校畢業(yè)設(shè)計指導(dǎo)[M]，北京：中國建材工業(yè)出版社，2002。

[9]  劉文劍，曹天河，趙維，夾具工程師手冊[M]，哈爾濱：黑龍江科學(xué)技術(shù)出版社，1987。

[10] 余光國，馬俊，張興發(fā)，機床夾具設(shè)計[M]，重慶：重慶大學(xué)出版社，1995。

[11] 東北重型機械學(xué)院，洛陽農(nóng)業(yè)機械學(xué)院，長春汽車廠工人大學(xué)，機床夾具設(shè)計手冊[M]，上海：上海科學(xué)技術(shù)出版社，1980。

[12] 李慶壽，機械制造工藝裝備設(shè)計適用手冊[M]，銀州：寧夏人民出版社，1991。

[13] 廖念釗，莫雨松，李碩根，互換性與技術(shù)測量[M]，中國計量出版社，2000：9-19。

[14] [王光斗，王春福，機床夾具設(shè)計手冊[M]，上?？茖W(xué)技術(shù)出版社，2000。

[15] 樂兌謙，金屬切削刀具，機械工業(yè)出版社，2005：4-17。

[16] Machine Tools N.chernor 1984.

[17] Machine Tool Metalworking John L.Feirer 1973.

致  謝

首先感謝老師給我的指導(dǎo)。在設(shè)計和論文寫作過程中，我始終得到老師的悉心教導(dǎo)和認(rèn)真指點，使得我的理論知識和動手操作能力都有了提高。在他身上，時刻體現(xiàn)著作為科研工作者所特有的嚴(yán)謹(jǐn)求實的教學(xué)風(fēng)范，勇于探索的工作態(tài)度和求同思變、不斷創(chuàng)新的治學(xué)理念。他們不知疲倦的敬業(yè)精神和精益求精的治學(xué)要求，端正了我的學(xué)習(xí)態(tài)度，使我受益匪淺。

另外，還要感謝同學(xué)，他們在尋找資料，解答疑惑，論文修改等方面，都給了我很大的幫助。

最后，感謝所有給予我關(guān)心和支持的老師和同學(xué)。

畢業(yè)設(shè)計(論文)外文資料翻譯學(xué) 院 ：機械工程學(xué)院 專 業(yè) 班 級 ：機械設(shè)計制造及其自動化 學(xué) 生 姓 名 ：學(xué) 號：指 導(dǎo) 教 師 ：外 文 出 處 ： 《Design of the DistributedArchitecture of a Machine-tool》 附 件 ：1.外文資料翻譯譯文； 2.外文原文 指導(dǎo)教師評語：簽名： 年 月 日分布式機床的設(shè)計FIP現(xiàn)場總線的用途Daping SONG, Thierry DIVOUX，費朗西斯勒帕熱自動化中心研究所的Nancy摘要：本文中我們基于FIP現(xiàn)場總線上提出了一種分布式控制系統(tǒng)。它將取代傳統(tǒng)的CNC(計算機數(shù)字控制裝置)用于機床上。該系統(tǒng)是由一套以微處理機為基礎(chǔ)的模塊(PC機、運動控制器、I/O接口) 利用FLP實時網(wǎng)絡(luò)相互聯(lián)接的。這主要是使每個模塊智能化以提高整個系統(tǒng)的靈活性和容錯能力。每個模塊都是一個分控系統(tǒng)，用于實現(xiàn)自己的分控任務(wù)，其中有些模塊用于運動控制，另一些模塊用于傳感器評價和執(zhí)行器調(diào)節(jié)。FIP決定了這些模塊之間的通訊（信息交流和同步），同時執(zhí)行任務(wù)分配以及設(shè)備布局分布。我們討論一些分布標(biāo)準(zhǔn)并描述實驗的執(zhí)行。1.引言近幾年，一直對分布式體系結(jié)構(gòu)進(jìn)行了許多研究。分布式體系結(jié)構(gòu)在系統(tǒng)集成上發(fā)揮主要作用。在機床控制域，目前 CNC 技術(shù)有它內(nèi)在的缺點。將幾根固定數(shù)量的軸容入 CIM 環(huán)境中是非常費時，靈活和不易的。超大規(guī)模集成電路微處理器技術(shù)和通信網(wǎng)絡(luò)的迅速發(fā)展使分布式控制成為可能。雖然逐步擴展沒有完全替代硬件更換但分布式控制系統(tǒng)的性能，模塊化，完整性和可靠性正在提高。它為替代控制系統(tǒng)架構(gòu)提供了一個很好的前景。本文致力于對分布式機床結(jié)構(gòu)的研究。它建立在智能設(shè)備與通信相聯(lián)系的基礎(chǔ)上。分布式機床的特點是分布式任務(wù)和分布式數(shù)據(jù)，且具有獨特的控制方法。它是結(jié)合標(biāo)準(zhǔn)設(shè)備和 FIP 系統(tǒng)總線設(shè)計而成，通過實驗證明該系統(tǒng)具有可執(zhí)行性，在實驗中該系統(tǒng)控制了復(fù)合軸系，成功執(zhí)行坐標(biāo)之間的關(guān)系同時也反應(yīng)了對傳感器值的變化。該論文結(jié)構(gòu)如下：第 2 部分描述了機床控制系統(tǒng)構(gòu)架。第 3 部分簡要介紹了 FIP 現(xiàn)場總線。第 4 部分概述了我們實驗的實施。最后，我們在第 5 部分總結(jié)了一些一般性意見和今后的研究前景。2.機床控制系統(tǒng)架構(gòu)該機床控制系統(tǒng)是一個實時多任務(wù)系統(tǒng)。其功能結(jié)構(gòu)如圖 1 所示。它包括三種單元：用戶接口/ 監(jiān)控單元/規(guī)劃單元，伺服單元，傳感器/制動器單位。這個系統(tǒng)的主要功能是用來控制工件的加工。它包括兩個不同的和相關(guān)的任務(wù)：● 為了確保軌跡的準(zhǔn)確性和對機床移動部件的速度控制● 為了調(diào)查定位（跟蹤）過程的正確執(zhí)行，環(huán)境變化的影響與指定操作的執(zhí)行或機床機件的運動同樣重要。例如：工具開關(guān)，冷卻，潤滑等。CAM 的制造日期圖 1：架構(gòu)功能按時間順序，這項任務(wù)也可分為兩個步驟：規(guī)劃控制程序規(guī)劃和執(zhí)行控制程序。第一步，機床機件沒有直接的方向，只有運動和被指定執(zhí)行的操作，這工作規(guī)劃/編程（軌跡，工具的選擇，其他加工參數(shù)采集）基本替換計算軸伺服控制系統(tǒng)機床構(gòu)件傳感器/制動器環(huán)境自動安全監(jiān)測加工是“數(shù)據(jù)采集和預(yù)處理”的一步。雖然在第二步，是控制的有效執(zhí)行。值得指出的是：在第二步由于多任務(wù)的性質(zhì)，并行處理是可行的。3.FIP 現(xiàn)場總線FIP系統(tǒng)被用來滿足分布式機床上實時通信的需要。在這一節(jié)中，我們簡要地解釋一下FIP系統(tǒng)的技術(shù)性能。FIP（工廠儀表協(xié)議）是網(wǎng)絡(luò)系統(tǒng)用于傳感器的驅(qū)動器和控制設(shè)備如PLCS，CNCS或機器人控制器之間的信息交換。FIP系統(tǒng)的結(jié)構(gòu)采用所謂的密封性以減少OSI模型(物理層,數(shù)據(jù)鏈路層和應(yīng)用層)，這種結(jié)構(gòu)使實時通信和常規(guī)的信息溝通之間有明顯的區(qū)別。在數(shù)據(jù)鏈路層中，相關(guān)服務(wù)一方面與其他傳遞信息服務(wù)可變轉(zhuǎn)讓。在應(yīng)用層中，我們可區(qū)分MPS服務(wù)（制造周期/非制造性規(guī)范），它采用來自數(shù)據(jù)鏈路層的信息設(shè)備所支持的MMS設(shè)備。FIP支持兩個傳輸媒體：屏蔽雙絞線和光纖。FIP允許各種各樣的布局，最長部分可達(dá)500米，至少有4個部分被中繼器代替。3種比特率被確定為：31.25k.比特/秒，1兆位/秒和2.5兆位/秒。FIP介質(zhì)訪問控制是集中的。所有轉(zhuǎn)讓都由the Bus Arbiter控制，時間安排轉(zhuǎn)移必須遵守時間要求。變量和信息之間的傳遞可采用定期配置或根據(jù)站的要求來轉(zhuǎn)讓，而在我們的應(yīng)用中，F(xiàn)IP只采用可變轉(zhuǎn)讓。FIP采用生產(chǎn)者和消費者的模樣來產(chǎn)生可變交流。變量對于生產(chǎn)者和消費者而言，是被確定的一個獨特的識別標(biāo)志，一套制作和消費變量可以集結(jié)在一個站，但是這些識別標(biāo)志不涉及任何物理地址站。圖2顯示了變化信息。廣播的 BA 標(biāo)識符 認(rèn)識的人 P和一些消費者?生產(chǎn)者發(fā)出的日期 P所有消費者接受的數(shù)據(jù) C 圖2：FIP系統(tǒng)的MAC圖象首先，the Bus Arbiter 廣播持有可變的標(biāo)示符，所有的節(jié)點接受幀并檢查變數(shù)是生產(chǎn)還是消費產(chǎn)生的或不給予影響。第三步：作為生產(chǎn)者的站必須響應(yīng)包含數(shù)據(jù)的幀。第四步：獲取消費者的變化價值并存儲。當(dāng)更新產(chǎn)生時，消費者和生產(chǎn)者便形成了。FIP有兩種類型的數(shù)據(jù)交流：周期性和非周期性的。在這兩種情況下，匯率發(fā)生情況如上圖（圖2）。在第一種情況下，the Bus Arbiter根據(jù)從配置要求價值相應(yīng)的標(biāo)識定期轉(zhuǎn)移。第二種情況下，the Bus Arbiter 可根據(jù)現(xiàn)有的帶寬產(chǎn)生轉(zhuǎn)讓請求信號。在我們的應(yīng)用中，實時的限制是非常嚴(yán)格的。為了使機床遵守給定的軌跡，軸的控制必須同步。這就要求和網(wǎng)絡(luò)連接的控制節(jié)點應(yīng)該同時接受開始命令，因此網(wǎng)絡(luò)必須播出命令。為了確保相同的瞬時命令能同時被幾個接受器接受，穩(wěn)定的傳輸是非常必要的。因此，一些傳感器例如運動控制傳感器就應(yīng)該要求定期調(diào)查限位開關(guān)以使網(wǎng)絡(luò)能定期無重大延誤的傳輸數(shù)據(jù)。一句話，像分布式機床的操作，像數(shù)據(jù)廣播的要求，時間和空間的一致性，定期傳輸不能滿足任何一般用途的網(wǎng)絡(luò)。然而，實時網(wǎng)絡(luò)例如FIP就是數(shù)據(jù)一種好的解決方法。4.實驗實施如圖3所示，我們的應(yīng)用目標(biāo)是要實現(xiàn)一個分布式的兩軸機床控制系統(tǒng)。它由以下設(shè)備分布在FIP總線的四個節(jié)點上。節(jié)點1：微機（i80486 微處理器）。它作為運營商終端。節(jié)點2.3：兩個相同的節(jié)點。每個均由微機（i80486）配備了運動控制器(克萊斯勒PCIOO + 克萊斯勒三菱商事100)。節(jié)點4：一個帶有傳感器/制動器作為輔助業(yè)務(wù)的可編程控制器（低溫100）。網(wǎng)絡(luò)：FIP和1比特/秒的雙絞線介質(zhì)間的選擇。軟件架構(gòu)的執(zhí)行系統(tǒng)是基于概念的多層次分布式控制。它有三種層次結(jié)構(gòu)，其中第二和第三層次可實現(xiàn)分配。它包括以下層次：分析層：控制任務(wù)的執(zhí)行選擇它被映射到微機的提供用戶界面的節(jié)點上。用來處理計劃收購和儲存，不同業(yè)務(wù)模式（手動和自動模式）的交換，起始點和終點以及其它各節(jié)點之間的計算和發(fā)送。慣例層：確定某一任務(wù)的控制算法它被映射到2種其他微機上（節(jié)點2和節(jié)點3）。這兩種微機具有根據(jù)給定的參數(shù)和命令（軌跡類型，速度，加速度等）進(jìn)行基本位移計算（插補）的功能。每個軸的插補算法是軟件設(shè)計的困難之一，因為軸控制分布后，每個中間坐標(biāo)軸的計算是獨立的。正確的算法設(shè)計可保證這些軸的連貫性。工藝層：執(zhí)行控制它包含兩種運動：運動控制器和可編程控制器。這些設(shè)備執(zhí)行伺服系統(tǒng)運動控制，處理加工件的舉行/緊縮政策，傳感器的評定和驅(qū)動器的調(diào)節(jié)使工具切換任務(wù)和監(jiān)控系統(tǒng)更安全。為了驗證擬議的架構(gòu)是否與時間限制和網(wǎng)絡(luò)能力相適應(yīng)，預(yù)期流量的估計是必要的。主要有兩種性質(zhì)的信息交流：● 命令從中央決定站（節(jié)點）傳到其它站?！?統(tǒng)計信息由站（節(jié)點）與站之間產(chǎn)生。例如:在我們的實驗平臺上,一些變數(shù)分布如下：節(jié)點1FIP 系統(tǒng) 節(jié)點2 節(jié)點4 節(jié)點3FIP系統(tǒng) FIP系統(tǒng)運動控制 運動控制傳感器和制動器X軸 Y軸圖3:硬件執(zhí)行5.結(jié)論本文中為滿足CIM的要求，我們的研究通過實驗實施進(jìn)一步達(dá)到審定。我們現(xiàn)在正致力于用來證明符合執(zhí)行實時限制的經(jīng)營架構(gòu)的仿真和性能分析的工作。我們的目標(biāo)不僅是一個試樣樣機，更是研究設(shè)計、優(yōu)化的分布式系統(tǒng)理論方案的發(fā)展。esign of the Distributed Architecture of a Machine-toolUsing FIP FieldbusDaping SONG, Thierry DIVOUX, Francis LEPAGECentre de Recherche en Automatique de NancyUniversite de Nancy I, BP239, 54506 Vandoeuvre-les-Nancy cedex, FranceAbstract: In this paper we propose a distributed control system based on FIP fieldbus. It is applied to machine-tool as a replacement for the traditional CNC (Computerized Numerical Controller). The system is composed of a set of microprocessor-based modules (PCs, motion controllers, I/OS, . ..) interconnected by FLP real-time network. The main idea is to enable each module to be intelligent, improving thus the flexibility and the fault tolerant capability of the whole system. Each module being a sub-control system, accomplishes its own control task, some of them for motion control and others for evaluating sensors and regulating actuators. The communication (information exchanges and synchronization) among these modules is ensured by FLP. This system allows both task distribution as well as equtpment topological distribution. We discuss some distribution criteria and describe an experimental implementation.1. IntroductionDistributed system architecture has been the subject of many research activities in recent years. It plays a major role in systems integration. In the machine-tool control domain, present CNC technology has its inherent shortcomings. It is centralized, limited to a fixed number of axis time-consuming, inflexible and difficult to be integrated in CIM environment. The rapid development of VLSI microprocessor technology and communication network enables the distributed control to be considered. Distributed control systems present the advantage of improving performance, modularity, integrity and reliability while allowing incremental expansion without complete hardware replacement. It offers a promising alternative to control system architecture.This paper is dedicated to study a distributed machine-tool architecture. It is based on intelligent devices interconnected on communication link. It is characterized by distributed tasks and distributed data, but with unique control access system. It is designed by using standard devices and FIP fieldbus and verified by a experimental implementation, in which the system controls a multi-axis machine to successfully execute a coordinated motion as well as to respond to sensors values changes.The paper is organized as follows. In section 2, the machine-tool control system architecture is described. Section 2 gives a brief description of FIP and Section 3 outlines our experimental implementation. We conclude in section 4 with some general remarks and future research perspectives.2. Machine-tool control system architectureThe machine-tool control system is a real-time and multitask system. Its classical functional architecture is shown in Fig.1. It consists of three units: user interface/supervisiou/programming unit, servo unit, and sensors/actuators unit. The main mission of this system is to control workpart machining. It includes two different and related tasks aspects: ●to ensure the precise trajectory and speed control of the mobile organs of machine-tool.●to survey the correct execution of this positioning (tracking) process, to react on environment changes as well as to perform the specified operations or actions upon machine-tool mechanics. such as tool switching, cooling, lubricating, etc. Fig. 1 Functional architectureChronologically, this mission is also divided into two steps: control program planning and control program executiug. In the first step, there is no direct action on machine-tool multitask nature: “data acquisition and preprocessing” step. While in the second step, the control is effectively executed. It is worth to note that in the second step, the parallelization is possible due to the mechanics, only the motions as well as the operations to be performed are specified. This is the “data acquisition and preprocessing” step. While in the second step, the control is effectively executed. It is worth to note that in the second step, the parallelization is possible due to themultitask nature.3.FIP fieldbusTo meet the real-time communication need in our distributed machine-tool, FIP is adopted. In this section, we briefly explain the main technical properties of FIP.FIP (Factory Instrumentation Protocol) is an industrial network designed for the exchange of information between sensors, actuators and control devices such as PLCs, CNCs or robotcontrollers. The architecture of FIP follows the so-calkd reduced OS1 model (Physical layer, Data link layer and Application layer). This architecture makes a clear distinction between real-time communication and conventional message communication. At Data Link layer, there are services associated to variable transfers on the one hand and conventional messaging services on the other hand. At Application layer, we distinguish the MPS (Manufacturing Periodic/aperiodic Specification) services which use variable transfers of Data Link layer from the MMS services which are supported by the messaging services of the Data Link layer.FlP supports two transmission media: shielded twisted pair and optical fiber. It allows for a wide variety of topologies. The maximum length of a segment is 500 m ;and at most 4 segmentsare authorized with repeaters. Three bit rates have been defined: 31.25 K.bit/s, 1 Mbit/s and 2.5 Mbit/s.FIP medium access control is centralized. All transfers are under control of the Bus Arbiter that schedules transfers to comply with timing requirements. Transfers of variables and messages may take place periodically according to system configuration or aperiodicalIy under request from any station. In our application, only variable transfer of FIP is used.For variable exchanges, FIP uses the producer-consumer model. ‘Variables are identified by a unique identifier known from the producer and the consumers. A set of produced and consumed variables can be regrouped in one station, but the identifier is not related to any physical address of stations. Fig. 2 shows the broadcast of a variable.Fig2 Principle of MAC protocol of FIPFirst, the Bus Arbiter broadcasts a frame that holds the identifier of the variable. All nodes receive the frame and check whether they are producer or consumer of the variable or not concerned. In a third step, the station that recognizes itself as the producer replies with a response frame that contains the data. In a fourth step, all the consumers of this variable capture the value and store it. The consumers and the producer are formed when the update takes place.FlP defines two types of data exchanges: periodic and aperiodic. In both cases, the exchange takes place as indicated above (Fig. 6). In the first case, the Bus Arbiter knows from the configuration that it has to request periodically the transfer of the value corresponding to an identifier. In the second case, transfer requests are signaled to the Bus Arbiter that will serve them according to the available bandwidth.For our application, the real-time constraints are very stringent. To make the machine-tool to follow an accurate trajectory, the control of the axis must be synchronized. This requires that the control nodes connected by a network should simultaneously receive the starting order, so the network should be able to broadcast orders. To ensure that an order of the same instant is received by several receivers, a spacec onsistency statue is also necessary. For responsiveness reason, some sensors like movement-limit switches should be polled periodically requiring that the network be able to transmit periodic data without important delays.In one word, for an application like distributed machine-tool, the requirements like broadcast of data , the time and space consistencies, the periodic transmission can not be met by any general-purpose networks, a real-time network like FIP is then a good solution.4. Experimental implementationAs shown in Fig. 3, our application is aiming to realize a distributed two-axis machine-tool control system. It is composed of the following devices distributed on four nodes over FIP fieldbus:node1: a microcomputer (i80486 microprocessor). It is used as operator terminal,node 2. 3: two identical nodes. Each consists of a microcomputer (i80486) equipped with a motion controller (DCX PClOO+DCX MC 100).node 4: a PLC (LT 100) with sensors/actuators for auxiliary operations.network: FIP with 1Mbits/s over twisted pair medium is chosen.The software architecture of the implemented system is based on the concept of multilayered distributed control. It has a three-level hierarchy and the distribution is realizes at the second and the third levels. It consists the following layers:Analysis layer: performs selection of the control tasksIt is mapped on to the microcomputer of node 1 which provides an user interface. It deals with the program acquisition and storage, switches the different operational modes (manual and automatic modes), computes and sends the start and arrival points coordinates as well as other orders to each other node respectively.Rule layer: determines the control algorithms for a given task.It is mapped on to the two other microcomputers (node 2 and 3) which function is elementary displacements calculation (by interpolation) according to the given parameters and orders ( trajectory type, speed, acceleration,. etc.).One of the software design difficulties is the interpolation algorithms for each axis. Because after axis control distribution, the calculation of the intermediate coordinates of each axis becomes independent, the coherence of these axis should be ensured by correct algorithm design.Process layer: executes the control.It includes the two motion controllers and the PLC. These devices executes servo systemmotion control, handles the workpart holding/tightening, tools switch tasks and monitors system safety by evaluation of sensors and regulation of actuators.In order to verify if the proposed architecture is suitable with time constraints and network capacity, in is necessary to estimate the expected traffic.There are mainly two natures of information exchanges:●orders from central decision station (node 1) to other stations.●state information produced by the stations ( node1) to other stations.For example concerning our experimental platform, we have delined some variables distributed as following: Fig3 Hardware implementation5. Conclusionln this paper, we investigated a distributed machine-tool architecture in order to meet CIM requirements. Our research reached the step of validation through the realization of anexperimental implementation. We currently work on the simulation and performance analysis of the operating architecture to justify that the implementation meets real-time constraints. Our objectiveis not only an experimental prototype, but also the development of the theoretical methodology for the design, optimization of this distributed system.