【正文】 自動(dòng)化中心研究所的 Nancy 摘要：本文中我們基于 FIP現(xiàn)場(chǎng)總線上提出了一種分布式控制系統(tǒng)。分布式體系結(jié)構(gòu)在系統(tǒng)集成上發(fā)揮主要作用。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(dòng)器單位。 現(xiàn)場(chǎng)總線 FIP系統(tǒng)被用來(lái)滿足分布式機(jī)床上實(shí)時(shí)通信的需要。 3種比特率被確定為： .比特 /秒， 1兆位 /秒和 /秒。 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。 在我們的應(yīng)用中，實(shí)時(shí)的限制是非常嚴(yán)格的。它由以下設(shè)備分布在 FIP總線的四個(gè)節(jié)點(diǎn)上。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。這些設(shè)備執(zhí)行伺服系統(tǒng)運(yùn)動(dòng)控制，處理加工件的舉行 /緊縮政策，傳感器的評(píng)定和驅(qū)動(dòng)器的調(diào)節(jié)使工具切換任務(wù)和監(jiān)控系統(tǒng)更安全。and at most 4 segments are authorized with repeaters. Three bit rates have been defined: , 1 Mbit/s and Mbit/s. FIP medium access control is centralized. All transfers are under control of the Bus Arbiter that schedules transfers to ply 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 producerconsumer 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 FIP First, 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 realtime constraints are very stringent. To make the machinetool to follow an accurate trajectory, the control of the axis must be synchronized. This requires that the control nodes connected by a work should simultaneously receive the starting order, so the work 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 movementlimit switches should be polled periodically requiring that the work be able to transmit periodic data without important delays. In one word, for an application like distributed machinetool, the requirements like broadcast of data , the time and space consistencies, the periodic transmission can not be met by any generalpurpose works, a realtime w