外文翻譯分布式機(jī)床的設(shè)計(jì)

1、 南京理工大學(xué)畢業(yè)設(shè)計(jì)(論文)外文資料翻譯系部： 機(jī)械工程系 專 業(yè)： 機(jī)械工程及自動化 姓 名： 學(xué) 號： 外文出處： design of the distributed architecture 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(jī)床的設(shè)計(jì)fip現(xiàn)場總線的用途daping song, thierry divoux，費(fèi)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(jì)算機(jī)數(shù)字控制裝置)用于機(jī)床上。該系統(tǒng)是由一套以微處理機(jī)為基礎(chǔ)的模

2、塊(pc機(jī)、運(yùn)動控制器、i/o接口) 利用flp實(shí)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(shí)現(xiàn)自己的分控任務(wù)，其中有些模塊用于運(yùn)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(shí)驗(yàn)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(jī)床控制域，目前cnc技術(shù)有它內(nèi)在的缺點(diǎn)。將幾根固定數(shù)量的軸容入cim環(huán)境中是非常費(fèi)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

3、速發(fā)展使分布式控制成為可能。雖然逐步擴(kuò)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(jī)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(jī)床的特點(diǎn)是分布式任務(wù)和分布式數(shù)據(jù)，且具有獨(dú)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(jì)而成，通過實(shí)驗(yàn)證明該系統(tǒng)具有可執(zhí)行性，在實(shí)驗(yàn)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(jī)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(shí)驗(yàn)的實(shí)施。最后，我們在第5部分總結(jié)了一些一般性

4、意見和今后的研究前景。2.機(jī)床控制系統(tǒng)架構(gòu)該機(jī)床控制系統(tǒng)是一個實(shí)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(jī)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(jī)床機(jī)件的運(yùn)動同樣重要。例如：工具開關(guān)，冷卻，潤滑等。 cam的制造日期工作規(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(jì)算傳感器/制動器環(huán)境自動安全監(jiān)測加工軸伺服控制系統(tǒng) 機(jī)床構(gòu)件圖1：架構(gòu)功能按時間順序，這項(xiàng)任務(wù)也可分

5、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(jī)床機(jī)件沒有直接的方向，只有運(yùn)動和被指定執(zhí)行的操作，這是“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(jī)床上實(shí)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(jī)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(shí)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

6、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，fip只采用可變轉(zhuǎn)讓。fip采用生產(chǎn)者和消費(fèi)者的模樣來產(chǎn)生可變交流。變量對

7、于生產(chǎn)者和消費(fèi)者而言，是被確定的一個獨(dú)特的識別標(biāo)志，一套制作和消費(fèi)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(fèi)者ç生產(chǎn)者發(fā)出的日期 p 所有消費(fèi)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(diǎn)接受幀并檢查變數(shù)是生產(chǎn)還是消費(fèi)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(fèi)者的變化價值并存儲。當(dāng)更新產(chǎn)生時，消費(fèi)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（

8、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(shí)時的限制是非常嚴(yán)格的。為了使機(jī)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(diǎn)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(yùn)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(jī)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

9、，實(shí)時網(wǎng)絡(luò)例如fip就是數(shù)據(jù)一種好的解決方法。4.實(shí)驗(yàn)實(shí)施如圖3所示，我們的應(yīng)用目標(biāo)是要實(shí)現(xiàn)一個分布式的兩軸機(jī)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(diǎn)上。節(jié)點(diǎn)1：微機(jī)（i80486 微處理器）。它作為運(yùn)營商終端。節(jié)點(diǎn)2.3：兩個相同的節(jié)點(diǎn)。每個均由微機(jī)（i80486）配備了運(yùn)動控制器(克萊斯勒pcioo + 克萊斯勒三菱商事100)。節(jié)點(diǎn)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(shí)現(xiàn)分配。它包括以下層次：分析層：控制任務(wù)的執(zhí)行選

10、擇它被映射到微機(jī)的提供用戶界面的節(jié)點(diǎn)上。用來處理計(jì)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(diǎn)和終點(diǎn)以及其它各節(jié)點(diǎn)之間的計(jì)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(jī)上（節(jié)點(diǎn)2和節(jié)點(diǎn)3）。這兩種微機(jī)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(jì)算（插補(bǔ)）的功能。每個軸的插補(bǔ)算法是軟件設(shè)計(jì)的困難之一，因?yàn)檩S控制分布后，每個中間坐標(biāo)軸的計(jì)算是獨(dú)立的。正確的算法設(shè)計(jì)可保證這些軸的連貫性。工藝層：執(zhí)行控制它包含兩種運(yùn)動：運(yùn)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(yùn)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

11、統(tǒng)更安全。為了驗(yàn)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(jì)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(diǎn)）傳到其它站。 統(tǒng)計(jì)信息由站（節(jié)點(diǎn)）與站之間產(chǎn)生。例如:在我們的實(shí)驗(yàn)平臺上,一些變數(shù)分布如下：fip系統(tǒng) 節(jié)點(diǎn)1 節(jié)點(diǎn)2 節(jié)點(diǎn)4 節(jié)點(diǎn)3 fip系統(tǒng) fip系統(tǒng) 運(yùn)動控制 運(yùn)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(shí)驗(yàn)實(shí)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(shí)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(jī)，更是研究設(shè)計(jì)、優(yōu)化的分布式系統(tǒng)理論方案的發(fā)展。design of

12、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 fie

13、ldbus. 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 b

14、e 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 e

15、xchanges 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

16、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

17、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 expansi

18、on 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 d

19、istributed 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 chan

20、ges.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. ma

21、chine-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 thi

22、s 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 t

23、o 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 i

24、s 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

25、 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 communicat

26、ion 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, cnc

27、s 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 as

28、sociated 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 th

29、e 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: 31.2

30、5 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 aperiodica

31、liy 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 regro

32、uped 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

33、 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 produc

34、er 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 val

35、ue 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

36、 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

37、 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

38、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 contro

39、l 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

40、100).node 4: a plc (lt 100) with sensors/actuators for auxiliary work: 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 distributi

41、on 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 operat

42、ional 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