外文翻譯--四輪轉向汽車的轉向特性及控制技術

1、<p><b>　　附　　錄</b></p><p><b>　　附錄A</b></p><p>　　Steering Behavior and Control Technology</p><p>　　0f Four—wheel Steering AutomobiIe</p><p>&

2、lt;b>　　ABSTRACT</b></p><p>　　This paper analyses the characteristics of car four-wheel steering control to, summarizes the principle of construction four-wheel steering cars. Introduced the four-whe

3、el steering system control strategy. Points out the four-wheel steering system control technology faces difficulties, and prospects the trend of its development. </p><p>　　Keywords: four-wheel steering; Stee

4、ring characteristics; Working principle; Control; Development; </p><p>　　1. Introduction </p><p>　　With modern road traffic system and the development of modern automobile technology, people on

5、the car's steering control performance and driving stability requirement is increasing day by day. As the most effective improve vehicle handling performance of a kind of active chassis control technology - four-whee

6、l steering technology. In the 1980s began in cars get application, and as the modern automobile industry and continuous development. Car four-wheel steering means in turn, the rear car can </p><p>　　2. The c

7、ar's steering four-wheel steering </p><p>　　2.1 4ws cars and 2ws steering process analysis</p><p>　　Ordinary two wheel steering can not only the front car around its own wheel rotation and r

8、elative to body deflection around the precision, then wheel rotation and not only deflection. When the driver turned the steering wheel, front wheel steering, changed directions face front tyre, produced a transverse for

9、ce, through the front wheel effect on body, make the body yawing and produce centrifugal force, the rear wheels cornering, produced change direction, participate in the sports car to. And th</p><p>　　In turn

10、, the 2ws car before active steering wheel rotation just makes passive steering. Obviously, 2ws cars in steering process from the steering wheel rotation to rear wheel steering movement in between the existence of certai

11、n lag time. This phase lag 2ws automobile steering characteristics make the servo sex becomes poor, and that the car steering radius increased. In addition, 2ws car at a high speed, the steering wheel Angle relative to c

12、ertain incremental, body yaw-rate and lateral acceler</p><p>　　2.2 4ws automobile steering way</p><p>　　According to the theory analysis and road test showed that a four-wheel steering can impro

13、ve the maneuverability and steering control stability of high speed, modern 4ws car is developed according to the guiding ideology. Generally speaking, in the process of steering cars in 4ws, according to different drivi

14、ng conditions, front and rear wheel steering Angle should follow certain rules between. At present, the front, rear typical 4ws deflection rules generally are described below:</p><p>　　(a) inverse phase stee

15、ring </p><p>　　As shown in figure A1 (a) shows, steering wheel Angle at low speeds or larger, front and rear inverse phase shift, realize that the rear wheels with the front deflect deflect instead, and with

16、 the steering wheel Angle deflection Angle increases and increases in a certain range. This redirection speed way can improve the manipulation of the car, reduce automobile portability turning radius, making cars maneuve

17、rability. Easy car turned turn, obstacle avoidance and driving, garage and parking. As f</p><p>　　(b) phase with steering </p><p>　　As shown in figure A1 (b) shows, in a high-speed or steering w

18、heel Angle is lesser, front and rear wheels with phase shift, realize that the rear wheels deflect the deflection direction with front wheel. Make the car body yaw-rate greatly reduce automobile body, can reduce the tend

19、ency of cornering undergo dynamic, guarantee the overtaking the highway, elevated highway, in and out, in the approach and flyovers insufficient steering state. Now, there are many 4ws cars take improving vehicle handl&l

20、t;/p><p>　?。╝）Reverse a steering （b）Coincidental a steering</p><p>　　Figure A1 four-wheel steering the front of the car, rear deflection rule</p><p>　　3. Four-wheel steering car com

21、ponents and working characteristics </p><p>　　4ws car is in front wheel steering system, and on the basis of suspension in cars on install a set of rear wheel steering system, both through certain questions

22、of contact, making cars in front wheel steering also participate in the meanwhile, rear wheel steering. After decades of research and development, have molding 4ws car type has a variety of, composition, structure is dif

23、ferent, working principle and control methods vary. The typical electric 4ws system mainly by the front wheel steering </p><p>　　4. Four-wheel steering control of the car </p><p>　　4ws system no

24、t only to realize the need for automotive steering movement, and guarantee the vehicle steering traveling stability. At present, in the research and development of automobile 4ws centered on improving car, the transient

25、manipulation stability as a starting point, explore due to rear brought car in response to changes, and adopts various rear wheel control strategy and produce different effect. Auto four-wheel steering control depends on

26、 tires were lateral force, four-wheel steering </p><p>　　4.1 control goals </p><p>　　That car in turn to basic keep PianJiao zero gravity side car. So can greatly improve the car to the steering

27、 wheel input dynamic response characteristics, largely improved yaw-rate and lateral acceleration of transient performance indicators, lower the body posture change. From the PianJiao zero target start. According to cert

28、ain control program is to realize the rear wheels to function is derived based four-wheel steering. Of course, the modern 4ws cars also have some other control goal reques</p><p>　　4.2 control strategy model

29、 based </p><p>　　The general situation of the studies are 4ws system based on a simple dof vehicle model of linear. This is just a kind of utopian mathematical model, when modeling overlooked in some of the

30、dynamic parameters of the car without considering changes, automobile driving produces in the process of many of the random uncertainties and not very accurate. Early 4ws controller design are based on linear dynamic equ

31、ation with the hypothesis, but due to the above reasons, make the design of control system</p><p>　　4.3 control method </p><p>　　Different cars driving performance requirements of steering and d

32、ifferent models of the car wheels deflection 4ws law is not the same. Thus, different 4ws vehicle USES control method is endless and same, various control method has its emphases respectively. At present, in some molding

33、 4ws with car on the control method basically has: </p><p>　　(a). The set than simply steering system 4ws. </p><p>　　(b). Than before, rear wheel steering front-wheel corner function 4ws system.

34、 </p><p>　　(c).Than before, rear wheel steering j speed function 4ws system is. </p><p>　　(d). The 4ws with first-order lagging system. </p><p>　　(e).With reversed-phase characteris

35、tics 4ws system </p><p>　　(f). With optimal control characteristics of 4ws system. </p><p>　　(g). Has since learning, white the ability to adjust the 4ws system. </p><p>　　Former fi

36、ve kinds of control system belong to classical control theory category, only to satisfy car under certain conditions, but also can't adapt to the need of motor sports of random changes, along with the computer techno

37、logy and some advanced control theory of development, 4ws system will towards adaptive, intelligent direction. </p><p>　　4.4 4ws system control technology development </p><p>　　At present, for r

38、esearch and development of car 4ws remains constant developing and perfecting stage. Although researchers from structure to control principle of four-wheel steering on have done a lot of research, 4ws technology have mad

39、e many progress. But, in the use of modern control theory of automotive steering control strategy choice of methods of determination and control, mainly depend on experience, the corresponding theoretical basis is still

40、very lack, 4ws technology not really into w</p><p>　　In the technology in relatively mature 4ws cars, most use electric hydraulic power 4ws system. With the rapid development of electronic technology, comput

41、er technology in cars, the wide application of electronic electric 4ws system will be the trend of the development of automobile 4ws. Although in 4ws system research and development has made great development, however, a

42、s the core technical problems 4ws system - 4ws system controller design, what on earth as the best control objectives? Adopt w</p><p>　　(a). Further research and development of new rear wheel steering actuat

43、ors and rear wheel steering transmission mechanism, improve the manipulation of steering portability, flexibility and steering Angle of accuracy. </p><p>　　(b). For 4ws system, further development, design hi

44、gh performance, high precision, high sensitivity sensor, in order to correctly detection car sports signal. </p><p>　　(c). Deep study turning the tyre during transient characteristics as the main factors, to

45、 join in the mathematic model of the system 4ws. </p><p>　　(d). The control theory and control into method is applied to the 4ws controller study.</p><p><b>　　附錄B</b></p><

46、p>　　四輪轉向汽車的轉向特性及控制技術</p><p><b>　　摘要</b></p><p>　　本文分析比較了四輪轉向汽車的轉向特點，概述了電控四輪轉向汽車的結構原理。介紹了四輪轉向系統(tǒng)的控制策略。指出了四輪轉向系統(tǒng)控制技術所面臨的困難，并展望其發(fā)展趨勢。</p><p>　　關鍵詞：四輪轉向；轉向特點；工作原理；控制；發(fā)展；&l

47、t;/p><p><b>　　1.引言</b></p><p>　　隨著現代道路交通系統(tǒng)和現代汽車技術的發(fā)展，人們對汽車的轉向操縱性能和行駛穩(wěn)定性的要求日益提高。作為改善汽車操縱性能最有效的一種主動底盤控制技術——四輪轉向技術。于二十世紀80年代中期開始在汽車上得到應用，并伴隨著現代汽車工業(yè)的發(fā)展而不斷發(fā)展。汽車的四輪轉向是指汽車在轉向時，后輪可相對于車身主動轉向，使汽車

48、的四個車輪都能起轉向作用。以改善汽車的轉向機動性、操縱穩(wěn)定性和行駛安全性。</p><p>　　2.四輪轉向汽車的轉向特性</p><p>　　2.1 4ws汽車與2ws汽車轉向過程分析</p><p>　　普通兩輪轉向汽車的前輪既可繞自身的輪軸自轉又可繞主銷相對于車身偏轉，而后輪只能自轉而不偏轉。當駕駛員轉動方向盤后，前輪轉向，改變了行駛方向，地面對前輪胎產生一個

49、橫向力，通過前輪作用于車身，使車身橫擺，產生離心力，使后輪產生側偏，改變前進方向，參與汽車的轉向運動。而4ws汽車的后輪與前輪一樣，既可自轉也能偏轉。當駕駛員轉動方向盤后，前、后輪幾乎同時轉向，使汽車改變前進方向，實現轉向運動。</p><p>　　2ws汽車在轉向時，前輪作主動轉向，后輪只是作被動轉向。顯然，2ws汽車在轉向過程中，從方向盤轉動到后輪參與轉向運動之間存在一定的滯后時間。2ws汽車的這種相位滯后特

50、性使汽車轉向的隨動性變差，并使汽車的轉向半徑增大。另外，2ws汽車在高速行駛時，相對于一定的方向盤轉角增量、車身的橫擺角速度和橫向加速度的增量增大，使汽車在高速行駛時的操縱性和穩(wěn)定性變差。而4ws汽車在轉向時，前、后輪都作主動轉向，在轉向過程中，靈敏度高，響應快，有效地克服了上述缺點。</p><p>　　2.2 4ws汽車的轉向方式</p><p>　　根據理論分析研究和大量路試表明，四

51、輪轉向能夠提高汽車轉向的機動靈活性和高速行駛時的操縱穩(wěn)定性，現代4ws汽車就是根據這一指導思想研制的。一般來說，4ws汽車在轉向過程中，根據不同的行駛條件，前、后輪轉向角之間應遵循一定的規(guī)律。目前，典型4ws汽車前、后輪的偏轉規(guī)律一般如下所述。</p><p><b>　　(a)逆相位轉向</b></p><p>　　如圖B1 (a)所示，在低速行駛或者方向盤轉角較大

52、時，前、后輪實現逆相位轉向，即后輪的偏轉方向與前輪的偏轉方向相反，且偏轉角度隨方向盤轉角增大而在一定范圍內增大。這種轉向方式可改善汽車低速時的操縱輕便性，減小汽車的轉彎半徑，提高汽車的機動靈活性。便于汽車掉頭轉彎、避障行駛、進出車庫和停車場。對轎車而言，若后輪逆相位轉向5°，則可減少最小轉向半徑約0 5m。</p><p><b>　　(b)同相位轉向</b></p>

53、<p>　　如圖B1(b)所示，在中、高速行駛或方向盤轉角較小時，前、后輪實現同相位轉向，即后輪的偏轉方向與前輪的偏轉方向相同。使汽車車身的橫擺角速度大大減小，可減小汽車車身發(fā)生動態(tài)側偏的傾向，保證汽車在高速超車、進出高速公路、高架引橋及立交橋時，處于不足轉向狀態(tài)?，F在，有許多4ws汽車把改善汽車操縱性能的重點放在提高汽車高速行駛的操縱穩(wěn)定性上，而不過分要求汽車在低速行駛的轉向機動靈活性。其工作特點是低速時汽車只采用前輪轉向

54、，只在汽車行駛速度達到一定數值后，后輪才參與轉向，進行同相位四輪轉向。</p><p>　?。╝）逆向位轉向 （b）同向位轉向</p><p>　　圖B1 四輪轉向汽車的前、后輪偏轉規(guī)律</p><p>　　3. 四輪轉向汽車的組成及工作特性</p><p>　　4ws汽車是在前輪轉向系統(tǒng)的基礎上，在汽車的后懸架上安裝一套后輪轉向系

55、統(tǒng)，兩者之問通過一定的方式聯系，使得汽車在前輪轉向的同時，后輪也參與轉向。經過幾十年的研究與開發(fā)，已經成型的4ws汽車類型有多種，組成、結構不同，控制方式及工作原理也各異。典型的電控4ws系統(tǒng)主要由前輪轉向系統(tǒng)、傳感器、ECU、后輪轉向執(zhí)行機構和后輪轉向傳動機構等組成。如圖B2所示，轉向時，傳感器將前輪轉向的信號和汽車運動的信號送入ECU進行分析計算，將處理后的驅動信號傳給后輪轉向執(zhí)行機構，后輪轉向執(zhí)行機構動作，通過后輪轉向傳動機構,

56、后輪偏轉。同時，ECU進行時監(jiān)控汽車運行狀況，計算目標轉向角與后輪實時轉向角之間的差值，來實時調整后輪的轉角。這樣，可以根據汽車的實際運動狀態(tài)，實現汽車的四輪轉向。一般的4ws汽車設有兩種轉向模式，既可進入4ws狀態(tài)，也可保持傳統(tǒng)的2ws狀態(tài)，駕駛員可通過駕駛室內的轉向模式開關進行選擇。當4ws汽車在行駛過程中電子控制系統(tǒng)出現故障時，后輪自動回到中間位置，汽車自動進入前輪轉向狀態(tài)，保證汽車像普通前輪轉向汽車一樣安全地行駛。同時，儀表板上

57、的“4ws”指示燈亮，警告駕駛員，故障情況被存儲在</p><p>　　圖B2 4ws控制工作原理圖</p><p>　　4．四輪轉向汽車的控制</p><p>　　4ws系統(tǒng)既要實現汽車轉向時所需的運動，又要保證汽車轉向時的行駛穩(wěn)定性。目前，在4ws汽車的研究和開發(fā)方面，主要是以改善汽車的瞬態(tài)操縱穩(wěn)定性為出發(fā)點，探索由于后輪參與轉向而帶來的汽車響應變化，以及采用

58、各種后輪控制策略而產生的不同效果。汽車四輪轉向的控制依賴于輪胎所受的側向力，四輪轉向能使汽車在轉向時，后輪直接參與對汽車橫擺運動和側向運動的控制。通過適時、精確地控制后輪的轉向角度，不僅可縮短轉向過程的瞬態(tài)響應，而且能主動地控制汽車的運動軌跡和姿態(tài)。在轉向過程中，使汽車的前進方向與其縱向中心線的方向一致，即使得汽車的方向角與姿態(tài)角重合，減小轉向時車體的側偏，提高了汽車的側向穩(wěn)定性。</p><p><b&g

59、t;　　4.1控制目標</b></p><p>　　使汽車在轉向時能夠基本保持汽車重心側偏角為零。這樣能夠大幅度提高汽車對方向盤輸人的動態(tài)響應特性，很大程度上改善了橫擺角速度和側向加速度的瞬態(tài)性能指標，降低車身姿態(tài)的變化。從側偏角為零的目標出發(fā)。按照一定的控制程序導出后輪轉向函數是實現四輪轉向的基礎。當然，現代的4ws汽車也有一些其它控制目標的要求。</p><p>　　4.2

60、控制策略的模型基礎</p><p>　　一般情況下進行的4ws系統(tǒng)的研究都是基于一個簡單的二自由度線性車輛模型。這只是一種理想化的數學模型，在建模時忽略了汽車的一些動力學參數的變化，沒有考慮汽車行駛過程中產生的許多隨機的、不確定因素，因而不是非常精確的。早期的4ws控制器設計都是基于跟隨線性動力學方程的假設，但由于上述原因，使得所設計的控制系統(tǒng)不一定滿足實際的需要，無法保證汽車轉向時的操縱穩(wěn)定性。</p&g

61、t;<p><b>　　4.3控制方法</b></p><p>　　不同的汽車對轉向行駛性能的要求不同，不同車型的4ws汽車的車輪偏轉規(guī)律也不一樣。因此，不同的4ws汽車所采用的控制方法不盡相同，各種控制方法分別有其側重點。目前，用在一些成型的4ws汽車上的控制方法主要有：</p><p>　　(a). 定前后輪轉向比的4ws系統(tǒng)。</p>

62、<p>　　(b)．前、后輪轉向比是前輪轉角函數的4ws系統(tǒng)。</p><p>　　(c). 前、后輪轉向比是車速函數的4ws系統(tǒng)。 </p><p>　　(d)．具有一階滯后的4ws系統(tǒng)。</p><p>　　(e)．具有反相特性的4ws系統(tǒng)。</p><p>　　(f). 具有最優(yōu)控制特性的4ws系統(tǒng)。 </p>

63、<p>　　(g). 具有自學習、白適應能力的4ws系統(tǒng)。</p><p>　　前五種控制系統(tǒng)屬于古典控制理論范疇，只能滿足汽車在某些特定條件下的需要，還不能適應汽車運動的隨機變化，隨著計算機技術和一些先進控制理論的發(fā)展，4ws系統(tǒng)將朝著自適應、智能化的方向發(fā)展。</p><p>　　4.4 4ws系統(tǒng)控制技術的發(fā)展</p><p>　　目前，對于4ws

64、汽車的研究和開發(fā)仍處于不斷發(fā)展和完善階段。盡管科研人員從結構到控制原理上對四輪轉向進行了大量的研究, 4ws 技術已取得不少進展。但是，在運用現代控制理論進行汽車轉向控制策略的確定和控制方法的選擇時，主要是依靠經驗，相應的理論依據還很缺乏，4ws技術沒有真正步入普及應用階段，在商用汽車上沒有得到廣泛應用。</p><p>　　在技術相對成熟的4ws汽車中, 大多數采用電控液壓動力4ws系統(tǒng)。隨著電子技術的飛速發(fā)展

65、，計算機技術在汽車中的廣泛應用，電控電動4ws系統(tǒng)將是4ws汽車的發(fā)展趨勢。雖然在4ws系統(tǒng)的研究和開發(fā)方面已經取得了很大的發(fā)展，但是，作為4ws系統(tǒng)的核心技術問題——4ws系統(tǒng)控制器的設計，究竟以什么作為最佳的控制目標?采用什么樣的控制方法?在該研究領域仍然沒有較為一致的看法。前已述及，早期進行的4ws系統(tǒng)的研究都是基于一個簡單的二自由度線性車輛模型，4ws控制器設計都是基于跟隨線性動力學方程的假設，采用PID控制策略。我們知道，4w

66、s系統(tǒng)的控制主要依賴于輪胎所受的橫向力。早期的研究是將汽車輪胎看成線性進行建模的, 一般的4ws控制也就基于輪胎所受的橫向力比例于車輪側偏角的假設，這種假設只是在橫向加速度較小的范圍內有效。當在橫向加速度較大的范圍內時，輪胎的側偏特性將進人非線性區(qū)域，輪胎側偏角對輪胎所受橫向力的響應不再呈比例關系，與輪胎所受的縱向力、垂直載荷等都有關系。實際上，汽車在轉彎行駛時，輪胎基本上都工作在非線性區(qū)域。此時，再用線性控制理論來進行研究，就顯得勉為

67、其難。4ws汽車操縱動力學問題是</p><p>　　(a)．進一步研究、開發(fā)新型的后輪轉向執(zhí)行機構和后輪轉向傳動機構，提高轉向時的操縱輕便性、靈活性和轉向角度的準確性。</p><p>　　(b)．針對4ws系統(tǒng)，進一步開發(fā)、設計高性能、高精度、高靈敏度的傳感器，以便于正確地檢測汽車的運動信號。</p><p>　　(c)．深人研究轉向過程中輪胎的瞬態(tài)特性，將其作