裝配圖大學(xué)生方程式賽車(chē)設(shè)計(jì)（總體設(shè)計(jì)）（有cad圖+三維圖）

裝配圖大學(xué)生方程式賽車(chē)設(shè)計(jì)（總體設(shè)計(jì)）（有cad圖+三維圖）,裝配,大學(xué)生,方程式賽車(chē),設(shè)計(jì),總體,整體,cad,三維 馬夫年會(huì)在福井。8月4日至6日,2003年 福井大學(xué)、日本 通過(guò)試驗(yàn)臺(tái)實(shí)施跨車(chē)輛通信系統(tǒng)為車(chē)輛排實(shí)驗(yàn) 跆拳道Min Kim Jae Weon崔 學(xué)校的機(jī)械工程和機(jī)械技術(shù)研究所 釜山國(guó)立大學(xué),609 - 735年,韓國(guó)釜山 文摘:本研究認(rèn)為通過(guò)試驗(yàn)臺(tái)實(shí)現(xiàn)問(wèn)題的跨車(chē)輛通信系統(tǒng)的車(chē)輛排實(shí)驗(yàn)。這個(gè)試驗(yàn)臺(tái),包括三個(gè)車(chē)輛和一個(gè)RCS規(guī)模(遠(yuǎn)程控制sbation),在前面是作為一種工具來(lái)評(píng)價(jià)仿真功能和全尺寸的車(chē)輛之間的研究。合作通信的車(chē)輛,車(chē)輛或路車(chē)輛保持相對(duì)間距小的車(chē)輛排扮演一個(gè)關(guān)鍵角色。然后:交通容量會(huì)增大。靜態(tài)排控制,汽車(chē)的數(shù)量保持不變,他在適當(dāng)?shù)墓潭ㄩg隔傳播的信息就足夠了,而動(dòng)態(tài)排控制如合并或者分立需要更靈活的網(wǎng)絡(luò)結(jié)構(gòu)的動(dòng)態(tài)協(xié)調(diào)的通信序列。在這項(xiàng)研究中,無(wú)線(xiàn)通信設(shè)備和可靠的協(xié)議實(shí)現(xiàn)了靈活的網(wǎng)絡(luò)架構(gòu),6位單片機(jī)收發(fā)信機(jī)使用在近距離、低成本情況。 關(guān)鍵詞:車(chē)輛排、無(wú)線(xiàn)通信系統(tǒng)、試驗(yàn)臺(tái) 1. 介紹 在大多數(shù)主要城市城市道路變得擁擠,因?yàn)樵絹?lái)越多的旅行需求超過(guò)公路通行能力。擁塞等問(wèn)題導(dǎo)致許多其他問(wèn)題:浪費(fèi)時(shí)間和精力,交通事故,污染等等。作為一個(gè)SD智能Tkansportation系統(tǒng)積極開(kāi)發(fā)成為這些問(wèn)題的全局最優(yōu)解。特別是,臺(tái)灣(智能車(chē)輛和公路系統(tǒng))是主要的主題，它在臺(tái)灣的目的是通過(guò)自動(dòng)化車(chē)輛和自動(dòng)公路改善安全作為增加highvmy能力。在臺(tái)灣,一個(gè)模范高效的車(chē)輛控制的方法通過(guò)提出了oons在路徑程序在平臺(tái)分組。車(chē)輛排是一組車(chē)輛在一個(gè)高速度與相對(duì)較小的間距一起旅行。車(chē)輛為什么在近地層排反饋控制規(guī)律是動(dòng)態(tài)耦合的。根據(jù)信息反饋和取決于這種a11信息是一個(gè)自動(dòng)加工合成的嗎。車(chē)輛跟蹤控制律,在一個(gè)車(chē)輛字符串內(nèi)動(dòng)態(tài)之間的相互作用會(huì)引起車(chē)輛不穩(wěn)定?？刂婆c信息鉛的車(chē)輛在一個(gè)排這是第一輛車(chē),前面的車(chē)輛只能保證穩(wěn)定在一個(gè)汽車(chē)。 測(cè)距雷達(dá)可以得到相對(duì)靠前的車(chē)輛的信息。但這信息是不能作為所有在一排的車(chē)輛使用。無(wú)線(xiàn)通信只允許獲得所有車(chē)輛中最靠前車(chē)輛的信息。 對(duì)于靜態(tài)排控制的車(chē)輛來(lái)說(shuō)這是足夠的，雷達(dá)獲取的信息保持不變,,因?yàn)樾畔⒌剿麄鞑ピ谶m當(dāng)固定間隔內(nèi),每個(gè)車(chē)輛不需要頻繁的更新的控制輸入。這個(gè)方案可以保證每個(gè)汽車(chē)在一排有一個(gè)支持系統(tǒng)、統(tǒng)一發(fā)送每一個(gè)周期的信息。如果為動(dòng)態(tài)排控制,如合并或分裂,更靈活網(wǎng)絡(luò)體系結(jié)構(gòu)是必需的。在這種情況下,因?yàn)闄C(jī)動(dòng)車(chē)輛為合并或分割需要頻繁?？刂戚斎氲母聲?huì)使信息被傳送到機(jī)動(dòng)車(chē)輛應(yīng)該比其他人多。因此,來(lái)傳輸這個(gè)信息更多機(jī)會(huì)是給領(lǐng)導(dǎo)車(chē)輛和操縱車(chē)輛的。在這個(gè)方案中,cominunicat.ion應(yīng)該協(xié)調(diào)有效的序列，因?yàn)閰f(xié)調(diào)的通信序列可能會(huì)實(shí)現(xiàn)容易被RCS(遠(yuǎn)程控制站)控制。 在這項(xiàng)研究中,無(wú)線(xiàn)通信系統(tǒng),可以通過(guò)“RCS”協(xié)調(diào)通信序列實(shí)現(xiàn)車(chē)輛縱向排實(shí)驗(yàn)。 2. 系統(tǒng)需求 能力是直接影響交通流的車(chē)輛排控制策略。需要在實(shí)時(shí)實(shí)現(xiàn)戰(zhàn)略時(shí)，控制策略可以衡量最大流量的流能力,衰減的間距錯(cuò)誤，它可以保證一個(gè)排的有效性和信息的數(shù)量,。在臺(tái)灣:恒間距和持續(xù)的進(jìn)展已被研究過(guò)是主要的控制手段。恒間距控制,在車(chē)輛跟蹤的基礎(chǔ)上而不斷進(jìn)展的控制,所需的控制間距期望的進(jìn)展是除了維護(hù)車(chē)輛本身增加車(chē)輛覆蓋之間的距離。恒間距使用的優(yōu)越性是在不斷進(jìn)展增加控制高速公路車(chē)輛的吞吐量,雖然常數(shù)進(jìn)展控制更優(yōu)惠但外部信息是必需的。在恒間距控制、外部信息是穩(wěn)定所需的字符串。無(wú)線(xiàn)通信系統(tǒng)可以利用這個(gè)外部信息傳遞。 在車(chē)輛排系統(tǒng)恒間距策略中,可以通過(guò)前面的車(chē)輛和車(chē)輛的信息獲得后面需要的車(chē)輛信息。這些信息包括位置、速度,加速度,和特定的命令的車(chē)輛，同時(shí),由于指定的緊急事件可能需要命令RCS獲得每個(gè)車(chē)輛的信息。在前面的研究中測(cè)試床上的車(chē)輛縱向排實(shí)驗(yàn)是發(fā)達(dá)的。試驗(yàn)臺(tái)的圖1顯示的包含三個(gè)量表車(chē)和RCS。在圖2中顯示每個(gè)車(chē)輛傳感器的數(shù)據(jù)采集的可用的信息包括操作系統(tǒng)的計(jì)算的控制命令,執(zhí)行機(jī)構(gòu)的驅(qū)動(dòng)和轉(zhuǎn)向?yàn)樽钣行У牟倏v,無(wú)線(xiàn)通信系統(tǒng)外部信息的交換,界面合成等基本功能。 圖1:測(cè)試平臺(tái)的配置 圖2:一個(gè)試驗(yàn)臺(tái)的配置工具的規(guī)模 在前面的研究中,433 MHz射頻模塊,BIM-433,用于實(shí)現(xiàn)求解無(wú)線(xiàn)通信系統(tǒng)的構(gòu)架這個(gè)TDMA(時(shí)分多址)。數(shù)據(jù)傳輸速率為38 kbps，這模塊是載波監(jiān)聽(tīng)算法不受支持的。因此,通信系統(tǒng)的性能對(duì)于調(diào)度序列控制同步和車(chē)輛是不足夠的。 對(duì)于每輛車(chē)穩(wěn)定運(yùn)動(dòng)測(cè)試,抽樣期的車(chē)輛應(yīng)低于40ms。傳感器用于試驗(yàn)臺(tái)可以滿(mǎn)意抽樣段30 ms。 傳輸數(shù)據(jù)(12個(gè)字節(jié))和導(dǎo)言(上圖3 ms)在38 kbps這則需要高于5 ms。至于提高性能和穩(wěn)健性的通信系統(tǒng),因?yàn)殚_(kāi)銷(xiāo)的增加更多的時(shí)間是必要的。此外,想要驗(yàn)證各種網(wǎng)絡(luò)序列調(diào)度算法需要更靈活的網(wǎng)絡(luò)結(jié)構(gòu)。這個(gè)無(wú)線(xiàn)通信系統(tǒng)是由雙方的硬件和軟件組成的。硬件提供了連接各種電臺(tái)(車(chē)輛或RCS)網(wǎng)絡(luò)硬件組件。軟件不僅提供了智能控制組件，該軟件還將提供一個(gè)靈活和可靠的交換協(xié)議通信數(shù)據(jù)。 3. 硬件實(shí)現(xiàn) 硬件的無(wú)線(xiàn)通信系統(tǒng)由以下組件組成:射頻前端模塊,接口芯片留給射頻前端模塊和MCU(microcontrol1er單位)。 這個(gè)圖3演示了配置的無(wú)線(xiàn)通信系統(tǒng)。硬件的架構(gòu)分為四層,如下所示： ·PHY層(物理層) ·PHY-MAC層(物理到MAC層） ·MAC層(介質(zhì)訪(fǎng)問(wèn)控制層） ·MAC應(yīng)用程序?qū)?MAC應(yīng)用程序?qū)? PHY層的實(shí)現(xiàn)是通過(guò)射頻前端模塊,RFW102收發(fā)器(發(fā)射機(jī)/接收機(jī))芯片研制的RFWaves有限公司)。PHY-MAC層由接口芯片,I/O(輸入/輸出)口的MCU,I/O驅(qū)動(dòng)在單片機(jī)里。獨(dú)家接口芯片,RFW-D100 RFWaves有限公司開(kāi)發(fā)的用于接口的rfw - 102.8)MAC層,它的使用是維持秩序的一個(gè)共享的介質(zhì),是在A(yíng)ICU的軟件。Mac層是在以后的一章討論,因?yàn)樗擒浖M件。在MAC應(yīng)用程序?qū)邮墙涌跓o(wú)線(xiàn)通信系統(tǒng)之間的部分,車(chē)輛RCS。 圖3:無(wú)線(xiàn)通信系統(tǒng)的配置 表1:RFW - 102的規(guī)格 物理媒介 DSSS,ISM波段(2.4 Ghz) 傳輸速率 高達(dá)1 mbps 帶寬 在-20分貝 30 Mhz 輸出功率峰值 2dBm 誤碼率 -80dBm 3.1 PHY層 PHY層實(shí)際處理的是一個(gè)無(wú)線(xiàn)通信系統(tǒng)之間的數(shù)據(jù)傳輸。在這一層,RFW -102收發(fā)器芯片用作射頻前端模塊。 RFW - 102的動(dòng)機(jī)是其高數(shù)據(jù)傳輸速率,減輕在連接到外部設(shè)備,對(duì)載波監(jiān)聽(tīng)算法的可用性。 表1顯示了規(guī)范的RFW - 102。 因?yàn)槭瞻l(fā)器芯片提供的最大輸出2dbm和靈敏度是-80 dbm.當(dāng)誤碼率(誤比特率)是在開(kāi)放傳輸可用于的30米。這個(gè)范圍適用于測(cè)試平臺(tái)車(chē)輛的使用規(guī)模的大小約為0.3米。 3.2 PHY-MAC 層 PHY-MAC層之間的接口是射頻前端模塊和MAC協(xié)議。層構(gòu)造以下組件:接口對(duì)射頻前端模塊預(yù)留芯片組,I/O端口利用單片機(jī)的單位驅(qū)動(dòng)I/O端口。 這個(gè)RFW-D100,RFIVaves有限公司開(kāi)發(fā)的作為接口芯片的。RFW-D100中芯片到RFW- 102芯片組是免費(fèi)的。它提供一個(gè)并行接口RFW - 102,使一個(gè)協(xié)議適合無(wú)線(xiàn)通信更容易實(shí)現(xiàn)。在這項(xiàng)研究中,MCU是負(fù)責(zé)MAC層協(xié)議和驅(qū)動(dòng)I/O控制的。接口芯片降低MCU實(shí)時(shí)要求處理的MAC協(xié)議。這個(gè)接口芯片類(lèi)似于內(nèi)存訪(fǎng)問(wèn),容易給MCU并行接口與射頻前端模塊。接口芯片轉(zhuǎn)換快串行輸入從射頻前端芯片到8打文字,然后適合一個(gè)8位MCU一起工作。此外,接口芯片要求一個(gè)更低的利率振蕩器的閑置模式.在空閑模式下,功耗RFW-102和RFW-D100大大減小了。這個(gè)接口芯片緩沖區(qū)數(shù)據(jù)通過(guò)第一字節(jié)FIFO(先入先出緩沖),這是可以給MCU訪(fǎng)問(wèn)RFW - DlOO更有效率。而不是閱讀1字節(jié)/中斷,MCU可以讀到在每一個(gè)中斷16字節(jié)。每個(gè)傳入字節(jié)中斷的情況,這減少了單片機(jī)在閱讀傳入的話(huà)說(shuō)的開(kāi)銷(xiāo)，因?yàn)槭∪チ硕褩Ｌ盍虾凸艿琅趴铡．?dāng)使用先進(jìn)先出,MCU支付所有的FIFO字節(jié)相同的開(kāi)銷(xiāo),而它不支付一個(gè)FIFO字節(jié)。 表2：Atmega 161L的規(guī)格 可操作的頻率 3.6864 MHz UART串行 2EA（最高1Mbps） 內(nèi)存 16K字節(jié)（閃） 1K字節(jié)（SRAM） 外部中斷 3EA 定時(shí)器/計(jì)數(shù)器 8-bit(2EA) 16-bit（1EA） 這個(gè)MCU實(shí)際由AIAC RFIV-D100處理協(xié)議和應(yīng)用D的。這個(gè)ATmega161L,由ATMEL Corp發(fā)展來(lái)用作MCU .表2顯示ATmega161L的規(guī)范。 在這項(xiàng)研究中,ATmega161L允許兩個(gè)外部中斷調(diào)用RFW-D100。 國(guó)家MAC層的變更中斷調(diào)用RFW-D100的事件。 根據(jù)變化的狀態(tài),執(zhí)行特定功能的MAC層,如接收、傳送、誤差檢驗(yàn),確認(rèn),和其他的數(shù)據(jù)處理。 3.3 MAC應(yīng)用程序?qū)? MAC應(yīng)用程序?qū)邮荕AC層和用程序(應(yīng)用程序)層之間接口。在這項(xiàng)研究中,應(yīng)用程序?qū)邮强刂泼枯v車(chē)的回路。這個(gè)應(yīng)用程序?qū)舆B接到可編程串行UART,這有一個(gè)中斷向量。因此,中斷調(diào)用的應(yīng)用程序?qū)幼鴺?biāo)是由國(guó)家的MAC層和特定的功能實(shí)現(xiàn)。此外,冗余的內(nèi)部SRAM是分配給接收和發(fā)送緩沖,它在FIFO中擴(kuò)展了RFW-D100。 然后就可以在FIFO中不斷發(fā)送和接收比RFW - D1OO長(zhǎng)尺寸的數(shù)據(jù) 。 4.軟件實(shí)現(xiàn) 圖4說(shuō)明了在這項(xiàng)研究中框圖的軟件配置。軟件配置分為三個(gè)層次，分類(lèi)如下: ·PHY-MAC層 ·MAC-APP層 ·MAC層 MAC層的MAC也分為MAC狀態(tài)和MAC數(shù)據(jù)。一般程序的MAC協(xié)議如下: 1.外部中斷調(diào)用的PHY層或者UART中斷調(diào)用的應(yīng)用程序?qū)蛹せ盍薓AC狀態(tài)管理。 2.MAC狀態(tài)管理檢查地位試用層,國(guó)家依照它的結(jié)果修改MAC。 3.根據(jù)最新對(duì)MAC狀態(tài)的修改,MAC數(shù)據(jù)管理控制數(shù)據(jù)流和RX / TX緩沖區(qū)。 4.然后,根據(jù)MAC的數(shù)據(jù)管理結(jié)果,MAC狀態(tài)管理設(shè)置新的MAC狀態(tài) 圖4 軟件配置的圖塊 兩個(gè)外部中斷的MCU是分配給分配層PHY的和UART中斷是分配給應(yīng)用程序?qū)印AC的過(guò)渡狀態(tài)是由這些中斷和8位定時(shí)器執(zhí)行控制時(shí)間的。因此,協(xié)議是保證配置邏輯是有效地改善和實(shí)時(shí)執(zhí)行的。此外,RX緩沖和TX緩沖區(qū)中MAC層有64字節(jié)的SRAM，RFW-D100的大小在主要約束在FIFO。 4.1可靠的協(xié)議 通常,通信是通過(guò)是一組很有效率、方便的數(shù)據(jù)包交流的。在這項(xiàng)研究中,數(shù)據(jù)包,見(jiàn)圖5,包括以下字段： ·前言:同步接收端 ·網(wǎng)絡(luò)ID:過(guò)濾數(shù)據(jù)包從其他網(wǎng)絡(luò) ·目的地：ID目的地 ·資料來(lái)源:ID資料來(lái)源 ·類(lèi)型/ Seq:數(shù)據(jù)包類(lèi)型/ Numher的序列 ·尺寸:整個(gè)數(shù)據(jù)包的大小 ·數(shù)據(jù):實(shí)際的數(shù)據(jù)傳輸 ·CRC:16位CRC檢查數(shù)據(jù)包的有效性 圖5:車(chē)輛與車(chē)輛間數(shù)據(jù)包的配置 數(shù)據(jù)域包含傳播的每一臺(tái)車(chē)輛的位置,速度,加速度數(shù)據(jù)。對(duì)于命令數(shù)據(jù)包的RCS;包括命令數(shù)據(jù)字段的RCS. 在這項(xiàng)研究中,射頻收發(fā)器是利用ISM波段。因?yàn)槭且粋€(gè)波段之間的共享資源網(wǎng)會(huì)經(jīng)歷許多無(wú)線(xiàn)應(yīng)用程序(如IEEE 802.11和藍(lán)牙,一個(gè)重疊在時(shí)間、頻率和空間域可能會(huì)干擾其他網(wǎng)絡(luò)狀況的。每個(gè)標(biāo)準(zhǔn)IEEE等802.11和藍(lán)牙使用包只有片段時(shí)間有定向協(xié)議和利用共享通道。一個(gè)協(xié)議的應(yīng)用程序會(huì)有ISM的使用時(shí)間，在秩序轉(zhuǎn)移所需的數(shù)據(jù)間隔的通道是免費(fèi)的或相對(duì)自由(干擾是弱)。當(dāng)一個(gè)節(jié)點(diǎn)想傳輸,節(jié)點(diǎn)聽(tīng)通道和檢查 通道是免費(fèi)的。機(jī)制RFW-DlOO支持CS(載波監(jiān)聽(tīng))這樣做。 為了確保一個(gè)數(shù)據(jù)包成功到達(dá)目的地(接收機(jī)),源(發(fā)射機(jī))需要在某一固定時(shí)間從接收機(jī)的一面得到一些驗(yàn)證。傳輸器將得到這個(gè)驗(yàn)證,從接收端獲得一個(gè)承認(rèn)包。如果發(fā)射機(jī)不得到一個(gè)承認(rèn)包,發(fā)射機(jī)嘗試重新發(fā)送數(shù)據(jù)分組。 4.2協(xié)議的行為 對(duì)于靜態(tài)排控制,因?yàn)槊恳惠v車(chē)不需要頻繁的更新控制輸入的劑量,傳輸數(shù)據(jù)包的機(jī)會(huì)均勻分配到每輛車(chē)。動(dòng)態(tài)排控制,由于機(jī)動(dòng)車(chē)輛為合并或分割要求頻繁更新的控制輸入,信息越多應(yīng)該傳給的數(shù)據(jù)包比其他機(jī)動(dòng)車(chē)輛多。這也是為什么通信序列動(dòng)態(tài)協(xié)調(diào)。該序列曾在崔和方舟子的工作算法中找到共通。這個(gè)協(xié)調(diào)通信序列通過(guò)RCS來(lái)實(shí)現(xiàn)。 圖6:協(xié)議行為的例子 圖6顯示了示例協(xié)議對(duì)一個(gè)周期無(wú)線(xiàn)通信系統(tǒng)之間的行為的研究。通信序列{ #1,# 2,# 3 }。RCS廣播主要的功能是,,每一個(gè)周期其他通信序列命令數(shù)據(jù)包和數(shù)據(jù)更新命令數(shù)據(jù)包。起初,RCS廣播命令通信序列 包。然后,每個(gè)車(chē)輛根據(jù)序列命令試圖傳播1.0通信數(shù)據(jù)包。對(duì)于同步的車(chē)輛控制,RCS廣播數(shù)據(jù)更新命令數(shù)據(jù)包，在最后的車(chē)輛(本研究在第三車(chē))傳輸?shù)臄?shù)據(jù)包。通信系統(tǒng)的每輛車(chē)已收到數(shù)據(jù)更新命令發(fā)送接收到其他車(chē)輛的數(shù)據(jù)并從其車(chē)輛獲取新數(shù)據(jù)。此外,因?yàn)橥ㄐ畔到y(tǒng),每輛車(chē)的嘗試將認(rèn)定為播放包同時(shí)承認(rèn)作為CSMA傳播。這個(gè)區(qū)間數(shù)據(jù)包的交流和確認(rèn)不到1毫秒。在這個(gè)階段的發(fā)展,因?yàn)閁ART的轉(zhuǎn)移率將是115.2 kbps,更多的時(shí)間是疲憊比之間的無(wú)線(xiàn)通信系統(tǒng)。自每輛車(chē)的取樣時(shí)間是40米的時(shí)間,期間的一個(gè)周期溝通是不到20 ms和兩個(gè)周期的溝通是疲憊比在每輛車(chē)的采樣時(shí)間。 4.3性能的協(xié)議 圖7顯示了在這項(xiàng)研究中實(shí)現(xiàn)無(wú)線(xiàn)通信系統(tǒng)。無(wú)線(xiàn)通信是安裝在每個(gè)規(guī)模車(chē)輛和試驗(yàn)臺(tái)的RCS。 圖8展示了驗(yàn)證無(wú)線(xiàn)通信系統(tǒng)的性能的裝置。作為d0或d1,32字節(jié)的數(shù)據(jù)包傳送在每個(gè)節(jié)點(diǎn)的固定順序。當(dāng)d0小于30米和dl是少于15米,在固定通信序列的案件包中沒(méi)有發(fā)現(xiàn)錯(cuò)誤。車(chē)輛規(guī)模大小是0.3米,兩個(gè)規(guī)模汽車(chē)所需的距離不到l.O m,結(jié)果是合理的。否則,對(duì)于通信序列的命令就會(huì)改變。任意時(shí)間,它驗(yàn)證的通信序列是到底是什么改變了。溝通序列修改的結(jié)果,見(jiàn)圖8,從源字段收到的數(shù)據(jù)包在RCS檢查。它表明,溝通序列在沒(méi)有錯(cuò)誤情況下也改變了。 圖7:無(wú)線(xiàn)通信系統(tǒng)的實(shí)現(xiàn) 圖8:驗(yàn)證過(guò)程的設(shè)置 5. 結(jié) 論 在這項(xiàng)研究中,無(wú)線(xiàn)通信系統(tǒng)車(chē)輛排實(shí)驗(yàn)通過(guò)試驗(yàn)臺(tái)實(shí)現(xiàn)。使用低投短程和大規(guī)?；旌霞蓭漕l收發(fā)器和一個(gè)%位單片機(jī),無(wú)線(xiàn)通信系統(tǒng)它在適合條件的實(shí)驗(yàn)中,現(xiàn)實(shí)和性能已被確認(rèn)的。使用可中斷單片機(jī)的定時(shí)器,保證了有效地實(shí)時(shí)操作。事實(shí)上,通信序列命令應(yīng)根據(jù)對(duì)車(chē)輛的傳輸狀態(tài)來(lái)變化。在未來(lái)的工作中RCS保持監(jiān)控車(chē)輛的狀態(tài)的功能。在這項(xiàng)研究中無(wú)線(xiàn)通信系統(tǒng)他會(huì)安裝在每個(gè)車(chē)輛和RCS的試驗(yàn)臺(tái)實(shí)現(xiàn),并將有 效用于開(kāi)發(fā)和驗(yàn)證的一個(gè)品種車(chē)輛排控制策略和序列調(diào)度算法。 圖9:命令改變序列的結(jié)果 引 用 [1]P.Varaiya,“智能汽車(chē)智能道路:問(wèn)題控制,”——IEEE自動(dòng)控制,38卷1號(hào),195 - 207頁(yè) [2]S.E . Shladover,C . A . Desoer, J.k·亨德里克,人工智能。Tomizuka,J . Walrand,W·B·zhang,D.H.McMahonh·Peng,Sheikholeslam,N . McKeown,“自動(dòng)車(chē)輛控制的發(fā)展路徑程序”,在交易車(chē)輛 IEEE技術(shù)卷。40歲,1號(hào),114 - 130頁(yè)。 [3] D. Swaroop, J. K. Hedrick “恒間距、智能車(chē)隊(duì)”的策略在自動(dòng)化高速公路系統(tǒng),動(dòng)態(tài)系統(tǒng),測(cè)量和控制卷。121、462470頁(yè)。 [4] H. S. Song, T. hl. Kim, and J. W. Choi “通過(guò)遠(yuǎn)程控制站開(kāi)發(fā)車(chē)輛縱向連排控制試驗(yàn)臺(tái),“2002年國(guó)際會(huì)議控制、自動(dòng)化和系統(tǒng)學(xué)報(bào),1039 - 1042頁(yè) [5] Choi, J. W., Fang, T. H., Kwong, S., and Y. H. Kim“通過(guò)編碼器遙控排合并-通信網(wǎng)絡(luò)的估計(jì)量序列算法,“IEEE工業(yè)電子、50卷1號(hào),,2003年。30-36頁(yè)。 161 J. W. Choi and T. H. Fang 最優(yōu)通信序列排用于遠(yuǎn)程控制的一個(gè)領(lǐng)頭車(chē),”出現(xiàn)在2003在控制應(yīng)用IEEE會(huì)議,2003 [7] -, RFW-102 ISM llansceiuer Chipset, RFW有限公司., 2002 181 -, RFW-DlOO Standard Interface, RFW有限公司., 2002 [9] -, ATmegalGlL, Rev.l228c-AVR-O8/02, AtmelCo., 2002 10 is Rollover mitigation control Unified chassis control velopmen rabili ed perfo controller and the human driver are investigated through a full scale driving simulator on the VTT which consists of a real time vehicle simulator a visual animation engine a visual display and suitable by a small a disproportionately the vehicle control system Accordingly in 2002 NHTSA time and method for rollover prevention that employs an optimal tire force ARTICLE IN PRESS Contents lists available at ScienceDirect Control Engineering Control Engineering Practice 18 2010 585 597 Yoon Kim fax 82 2 882 0561 automotive industry as it does not consider the effects of suspension deflection tire traction aspects or the dynamics of Liu proposed a robust active suspension for rollover prevention Yang and 2 the type which indirectly influences roll motions by controlling the yaw Vehicle stability Virtual test track Design and evaluation of a unified chass prevention and vehicle stability improvement Jangyeol Yoon a Wanki Cho a Juyong Kang a Bongyeong a School of Mechanical and Aerospace Engineering Seoul National University 599 Gwanangno b Mando Corporation Central R it also calculates the desired braking force and the desired yaw moment for its objectives Each control mode generates a control yaw moment and a longitudinal tire force in line with its coherent objective The lower level controller calculates the longitudinal and lateral tire forces as inputs of the control modules such as the ESC and the AFS 2 1 The upper level controller decision desired braking force and desired yaw moment The upper level controller consists of three control modes and a switching logic A control yaw moment and the longitudinal tire force are determined in line with its coherent control mode so that the switching across control modes is performed on the basis of the threshold Based on the driver s input and sensor signals the upper level controller determines which control mode is to be selected as shown in Fig 2 In this study RI is used to detect an impending vehicle rollover where the RI is a dimensionless number that can indicate the risk of vehicle rollover and it is calculated through the measured lateral acceleration a y the estimated roll angle f the estimated roll rate f and their critical values which depend on the vehicle geometry in the following manner Yoon et al 2007 In 1 C 1 C 2 and k 1 are positive constants 0oC 1 o1 0oC 2 o1 C 1 and C 2 are weighting factors which are related to the roll states and the lateral acceleration of the vehicle and k 1 is a design parameter which is determined by the roll angle rate phase plane analysis These parameters in 1 are determined through a simulation study undertaken under various driving situations and tuned such that an RI of 1 indicates wheel lift off A detailed description for the determination of the RI is provided in previous research Yoon et al 2007 The lateral acceleration can easily be measured from sensors that already exist on a vehicle equipped with an ESC system However additional sensors are needed to measure the roll angle and the roll rate although it is difficult and costly to directly measure these Schubert Nichols Fig 1 RI VS based UCC strategy RI C 1 f t C12 C12 C12 C12 f th f t C12 C12 C12 C12 C12 C12f th f th f th 0 1 A C 2 a y C12 C12 C12 C12 a y c C18C19 1C0C 1 C0C 2 f t C12 C12 C12 C12 f t 2 f t C16C17 2 r 0 B B 1 C C A f fC0k 1 f C16C17 40 RI 0 f fC0k 1 f C16C17 r0 8 1 J Yoon et al Control Engineering Practice 18 2010 585 597 587 Fig 2 Control modes for the proposed UCC system ARTICLE IN PRESS 012345678 Time sec No control 43 2mph Control 45 6mph Roll angle 012345678 Time sec No control 43 2mph Contro l 45 6mph Lateral acceleration No control 43 2mph Control 45 6mph 15 10 5 0 5 10 15 15 10 5 0 5 10 15 1 1 5 Roll angle deg sec ay m s J Yoon et al Control Engineering Practice 18 2010 585 597588 Wallner Kong in this the sliding surface and the sliding condition are defined as follows s 1 gC0g des 1 2 d dt s 1 2 s 1 s 1 rC0Z 1 s 1 jj 9 where Z 1 is a positive constant The equivalent control input that would achieve s 1 0 is calculated as follows M z eq C0I z 2 C0a C f b C r I z bC0 2 a 2 C f b 2 C r I z v x g 2a C f I z D f 10 Finally the desired yaw moment for satisfying the sliding condition regardless of the model uncertainty is determined as follows M z M z eq C0K 2 sat gC0g des F 1 C18C19 11 where F 1 is a control boundary and the gain K 2 which satisfies the sliding condition is calculated as follows K 2 I z F yf I z C0abC0a 2 g aD f C12 C12 C12 C12 F yr I z bbC0b 2 g C12 C12 C12 C12 g des C12 C12 C12 C12 Z 2 C26C27 12 2 1 2 Desired braking force for rollover prevention the ROM mode If the RI increases to a predefined RI threshold value which can predict an impending rollover the ROM control input should be applied to the vehicle in order to prevent rollover Rollover prevention control can be achieved through vehicle speed control and the desired braking force is determined in this section to control the speed In addition the desired yaw moment as determined in the previous section is also applied to the vehicle to improve the maneuverability and the lateral stability As mentioned previously since vehicle rollovers occur at large lateral accelerations the desired lateral acceleration should be defined and can be determined from the RI cf Eq 1 as follows a y des 1 C 2 RI tar C0C 1 f t C12 C12 C12 C12 f th f t C12 C12 C12 C12 C12 C12f th f th f th 0 1 A C0 1C0C 1 C0C 2 f t C12 C12 C12 C12 f t 2 f t C16C17 2 r 0 B B 1 C C A 8 9 a y c 13 In 2 the target RI value RI tar is set to 0 6 The desired vehicle speed for obtaining the desired lateral acceleration is calculated from the lateral vehicle dynamics as follows Yoon et al 2009 v x des 1 g a y des C0 a y m C0v x g C0C1C8C9 14 The desired braking force to yield the desired vehicle speed is calculated through a planar model as shown in Fig 7 and through the sliding mode control law Fig 7 shows a planar vehicle model including the desired braking force DF x and the dynamic equation for the x axis is described as follows m v x F xr F xf cosD f C0F yf sinD f mv y gC0DF x 15 By the assumption of having small steering angles Eq 15 can be rewritten in terms of the derivative of the vehicle speed as follows v x 1 m F xr F xf C0F yf D f v y gC0 1 m DF x 16 Fig 7 Planar model including the desired braking force the use of braking because the ESC module has some negative ARTICLE IN PRESS effects as the simple distribution scheme determines only the differential braking input for the ESC module These two schemes are switched in accordance with the protocol for switching across control modes in the upper level controller and the only ESC module is used in the ROM mode since the optimized distribution scheme for the AFS and ESC modules provides a very small braking to each wheel which cannot decrease the vehicle speed which is essential for preventing rollover Moreover the slip angle of the tire is proportionally increased with the lateral acceleration as shown in Fig 8 Since vehicle rollovers generally occurs at large lateral acceleration the slip angle of the tire is also very large in the ROM mode situation The AFS module cannot generate the lateral tire force in large slip angle situations as shown in Fig 9 therefore the AFS module is not used in the ROM mode that is the ESC is the most effective for the ROM mode For this reason only the ESC control module is used for the ROM mode 2 2 1 Tire force distribution in vehicle stability situations ESC g ESC b mode In vehicle stability situations that do not have risk of rollover the control interventions for maneuverability ESC c and for lateral stability ESC b are activated When the lateral accelera tion is small enough so that the slip angle is small the characteristics of the lateral tire force lie within the linear region as shown in Fig 9 In these situations only the AFS control module is applied and the AFS control input is determined through the consideration of the 2 D bicycle model as follows Slip angle deg ESCAFS ESC AFS Lateral tire force N 0 36 Fig 9 Characteristics of the lateral tire force 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 8 6 4 2 0 Lateral acceleration g Slip angle deg Vehicle Stability Rollover Prevention Fig 8 Relation between the lateral acceleration and the slip angle J Yoon et al Control Engineering Practice 18 2010 585 597 591 Fig 10 Coordinate system corresponding Dd f M z 2aC f 19 When the lateral acceleration increases greatly the combined control inputs that are based on the ESC and AFS modules are applied Since the ESC module has some negative effects such as the degradation of ride comfort and the wear of tires and brakes the optimized coordination of tire forces is focused on minimizing the use of braking An optimal coordination of the lateral and longitudinal tire forces for the desired yaw moment is determined through the Karush Kuhn Tucker KKT conditions Cho Yoon two of these constraints are determined as follows f x C0 t 2 D 1 DF x1 aD 2 DF y1 C0M Z 0 23 g x DF x1 F x1 2 DF y1 F y1 2 C0m 2 F z1 2 r0 24 In the above D 1 1 F z3 F z1 D 2 1 F z2 F z1 The equality constraint in 23 means that the sum of the yaw moment generated by the longitudinal and the lateral tire forces should be equal to the desired yaw moment The inequality constraint in 24 means that the sum of the long itudinal and the lateral tire forces should be less than the friction forces on the tire From 22 24 the Hamiltonian is defined as follows H DF x1 2 l C0 t 2 D 1 DF x1 aD 2 DF y1 C0M Z C18C19 r DF x1 F x1 2 DF y1 F y1 2 C0m 2 UF z1 2 c 2 C16C17 25 where l is the Lagrange multiplier c the slack variable and r the semi positive number First order necessary conditions about the Hamiltonian are determined by the Karush Kuhn Tucker condition theory as follows H DF x1 2DF x1 C0 t 2 D 1 l 2r DF x1 F x1 0 26 H DF y1 aD 2 l 2r DF y1 F y1 0 27 H l C0 t 2 D 1 DF x1 aD 2 DF y1 C0DM Z 0 28 rg x r DF x1 F x1 2 DF y1 F y1 2 C0m 2 F z1 2 C16C17 0 29 J Yoon et al Control Engineering Practice 18 2010 585 597592 F xF max xR max F F xF F xR F zF F zR Fig 11 Friction circles of the front and rear tires Fig 12 Hardware configuration of the driving From 29 two cases are derived with respect to r and g x as follows Case 1 r 0 g x o0 Case 2 r40 g x 0 Case 1 means that the sum of longitudinal and lateral tire forces is smaller than the friction of the tire On the other hand Case 2 means that the sum of the longitudinal and lateral tire forces is equal to the friction of the tire The solutions of the optimization problem represented in 3 41 can be obtained for both cases If the desire yaw moment is positive M z 40 the solutions are obtained as follows Case 1 DF x1 0 DF y1 M Z aD 2 0 B 30 Case 2 DF x1 C0 F x1 kz 1 k 2 m 2 F z1 2 C0 kF x1 C0z 2 q 1 k 2 DF y1 tD 1 2aD 2 DF x1 1 aD 2 M Z 31 where k tD 1 2aD 2 and z 1 aD 2 M Z F y1 The brake pressure for the ESC module and the additional steering angle for the AFS module are determined from 32 simulator with a human in the loop ARTICLE IN PRESS as follows DD f DF yi C f P Bi r wf DF xi K Bi i 1 2 0 B B B 32 In 32 K Bi is the brake gain and r wf the radius of the wheel When the desired yaw moment is negative M z o0 the tire forces can be obtained in a manner similar to 30 and 31 2 2 2 Tire force distribution in rollover situations ROM mode In the previous sections the desired braking force which should be subjected to the vehicle for rollover prevention and the desired yaw moment for reducing the error in the yaw rate have been determined By utilizing the above two values a braking force distribution is accomplished simply to help prevent vehicle rollover while ensuring that the vehicle follows the intended path of the driver The forces of the vehicle can be determined kinematically as follows DF x left 1 2 DF x M z t 1 M z 8 33 0 2 4 6 8 1012141618 Time sec Yaw rate 024681012141618 Time sec Lateral acceleration 0 2 4 6 8 10 12 14 16 18 20 10 0 10 20 6 4 2 0 2 4 6 0 2 4 50 0 50 Time sec Yaw rate deg s Lateral acceleration m s 2 Steering wheel angle deg Vehicle test Simulator Vehicle test Simulator Vehicle test Simulator Steering wheel angle J Yoon et al Control Engineering Practice 18 2010 585 597 593 0 2 4 6 8 10 12 14 16 18 Time sec Vehicle test Simulator Roll angle 4 2 Roll angle deg Fig 13 Comparison between actual vehicle test data and the driving simulator for the slalom test DF x right 2 DF x C0 t The braking forces of the left and right sides are obtained by substituting 18 and 11 into 33 Fig 11 shows the friction circles of the front and rear tires and the traction force determined through the shaft torque is applied at the front tire and the drag force is applied at the rear tire The maximum braking forces of the front and rear tires can be determined as follows DF xf max F xf C0 mF zf 2 C0 F yf 2 q 34 DF xr max C0F xr C0 mF zr 2 C0 F yr 2 q 35 The braking force distributions of the front and rear tires are achieved by using equations from 33 through to 35 as follows DF xr left DF xr left max C12 C12 C12 C12 DF xf left max C12 C12 C12 C12 DF xf left 36 DF xr right DF xr right max C12 C12 C12 C12 DF xf right max C12 C12 C12 C12 DF xf right 37 In the above DF xf left DF xr left DF x left and DF xf right DF xr right DF x right 80km h Obstacle Fig 14 The test scenario obstacle avoidance ARTICLE IN PRESS The braking pressure of the front left wheel can be determined as follows P Bf left r wf DF xf left K Bf if DF xf left oDF xf max r wf DF xf max K Bf if DF xf left ZDF xf max 8 38 The other tire forces can be obtained in a manner similar to 38 3 Full scale driving simulator The configuration of the full scale driving simulator for the human in the loop system is shown in Fig 12 consisting of four parts a real time RT simulation hardware a visual graphical engine a human vehicle interface and a motion platform The host computer in Fig 12 is utilized to modify the vehicle simulation program and to display the current vehicle status The RT simulation hardware calculates the variables of the vehicle model represented using a CARSIM model controlled by the UCC controller with measured driver reactions By the use of the vehicle behavior information obtained using RT simulation hardware the visual graphical engine projects a visual representation of the driving conditions to the human driver via a beam projector with a 100 in screen who interacts with the 3 D virtual simulation and the kinesthetic cues of the simulator body The driver s responses are acquired through the steering wheel angle brake pressure and throttle positioning sensors as shown in Fig 12 The motion platform provides kinesthetic cues which are related to the behavior of the vehicle with regard to the human driver An actual full sized braking system including a vacuum booster master cylinder calipers etc is implemented in the simulator so that the feel of the braking action is similar to that of an actual vehicular brake pedal In the case of the steering wheel a spring and damper are used to produce the reactive forces of the steering wheel where the spring and damper characteristics are adjusted to make the feel of the steering wheel similar to that of an actual vehicle being driven in the high speed range 3 1 Configurations of the driving simulator The most important feature of the driving simulator is to guarantee real time performance and so all the subsystems are 8 0 200 100 100 200 100 120 10 Steering wheel angle deg w o control RI based ROM RI VS based UCC RI based ROM 0 2 4 6 8 10 12 14 16 18 0 2 4 6 8 10 12 14 16 18 Time sec Time sec Steering wheel angle Lateral acceleration 1 0 5 0 0 5 1 0 1 5 2 Lateral acceleration g w o control RI based ROM RI VS based UCC w o control RI based ROM RI VS based UCC J Yoon et al Control Engineering Practice 18 2010 585 597594 10 5 0 5 Roll angle deg RI VS based UCC 0 2 4 6 8 10 12 14 16 18 Time sec Roll angle 0 2 4 6 8 101214161 0 20 40 60 80 Velocity km h w o control RI based ROM RI VS based UCC w o control Time sec Velocity Fig 15 Driving tests results using the full scale 024681012141618 Time sec Rollover index 0 2 4 6 8 10 12 14 16 18 0 5 0 0 5 Time sec Yawrate error deg sec w o control RI based ROM RI VS based UCC Yaw rate error 0 5 1 Rollover index simulator based on the VTT ARTICLE IN PRESS to the simulator body as shown in Fig 12 and the motion trajectories If the UCC control input is not applied the vehicle rolls over in this situation It is clear from Fig 15 e that the RI increases over unity in the absence of control Further the roll angle and lateral acceleration also increase to large values as shown in Fig 15 c and d In addition because this situation is very severe the vehicle deviates from the lane as shown in Fig 17 It can be seen that the driver s detects the dropped obstacle at about five seconds and immediately tries to avoid the obstacle by changing lane The vehicle velocities at about five seconds of three cases viz NON control RI based ROM and RI VS based UCC are similar to each other as shown in Fig 15 b When the UCC control is activated two of the control systems yield good resistance to rollover as shown in Fig 15 c and e As the RI based ROM system intends to control the vehicle in a direction that is opposite to the driver s intention the yaw rate 0 2 4 6 8 1012141618 Time sec Brake pressures MPa Front left Front right Rear left Rear right RI based ROM system 0 2 4 6 8 1012141618 0 5 10 15 20 0 2 4 6 8 10 Time sec Brake pressures MPa Front left Front right Rear left Rear right RI VS based UCC system Fig 16 Brake pressures J Yoon et al Control Engineering Practice 18 2010 585 597 595 platform allows displacements up to a maximum of about 710 cm heave and 7101 roll and pitch The motion platform renders the linear and angular accelerations of the simulated vehicle model as computed by the RT simulation hardware so that the human driver gets an impression that s he is driving an actual vehicle by means of the kinesthetic cues generated by the motion platform and from the visual representation of the driving situation provided by the visual graphical engine 3 2 Validation of the vehicle simulator The driving simulator used in this paper is evaluated via actual vehicle test data and Fig 13 shows the results of a slalom test in which the driver maintains an approximately constant vehicle speed of about 60 km h The cone width is 30 m The magnitude and frequency of the driver s steering inputs are almost identical in both the vehicle test results and the driving simulator as shown in Fig 13 a The vehicle responses in terms of the yaw rate the lateral acceleration and the roll angle are also quite similar to the actual test results as shown in Fig 13 b d The comparison between the driving simulator and actual vehicle test results shows that the proposed driving simulator is feasible for describing actual vehicle dynamic behaviors This means that the driving simulator accurately reproduces actual driving conditions 4 Evaluation of the proposed UCC based on a VTT Tests using the full scale driving simulator based on the VTT have been conducted to verify the proposed RI VS based UCC control algorithm and its performance with that of the previous RI based ROM control system are compared The tests based on the VTT have been conducted by thirteen drivers and the results are analyzed and summarized here The test scenario is set to the obstacle avoidance situation shown in Fig 14 so that when a driver follows the preceding vehicle moving at a constant speed of 90 km h in a straight lane and an object is dropped suddenly from the preceding vehicle In this situation the driver abruptly steers the vehicle to avoid the dropped obstacle and the vehicle is placed in a dangerous situation Moreover in this extreme situation vehicle rollover is possible and there may be a loss of maneuverability without an UCC control system Tests have been conducted by thirteen drivers Fig 1