英文翻譯外文文獻翻譯346四輪轉向汽車的轉向特性及控制技術.docx

1 附 錄 附錄 A Steering Behavior and Control Technology 0f Four wheel Steering AutomobiIe ABSTRACT This paper analyses the characteristics of car four-wheel steering control to, summarizes the principle of construction four-wheel steering cars. Introduced the four-wheel steering system control strategy. Points out the four-wheel steering system control technology faces difficulties, and prospects the trend of its development. Keywords: four-wheel steering; Steering characteristics; Working principle; Control; Development; 1. Introduction With modern road traffic system and the development of modern automobile technology, people on the cars 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-wheel 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 be relative to body active steering, that the car can be up to four wheels role. To improve the car turned to maneuverability, handling stability and driving safety. 2. The cars steering four-wheel steering 2.1 4ws cars and 2ws steering process analysis Ordinary two wheel steering can not only the front car around its own wheel rotation and relative 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 force, through the front wheel effect on body, make the body yawing and produce centrifugal force, the rear wheels cornering, 2 produced change direction, participate in the sports car to. And the rear and front car 4ws as, can rotation can also deflection. When the driver turned the steering wheel, front and rear wheels, that car almost at the same time to change direction, realize steering movement. In turn, 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 certain 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 certain incremental, body yaw-rate and lateral acceleration incremental increases, made the car at a high speed handling and stability becomes poor. And in turn, the car 4ws has done before, rear wheel steering, active in the process of steering, high sensitivity, fast response, effectively overcome the shortcomings. 2.2 4ws automobile steering way According to the theory analysis and road test showed that a four-wheel steering can improve 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 driving 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: (a) inverse phase steering 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 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 maneuverability. Easy car turned turn, obstacle avoidance and driving, garage and parking. As for cars, if rear inverse phase 5 , then turned can reduce minimum steering radius was about 0.5. (b) phase with steering As shown in figure A1 (b) shows, in a high-speed or steering wheel 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 tendency 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 handling performance focuses on making cars on high-speed steering stability, without excessive demands in low-speed driving car course-altering maneuvers flexibility. The features is low by front wheel steering car only when only in car speeds, after up to a certain value, rear, only participate in steering phase 3 with four-wheel steering. （ a） Reverse a steering （ b） Coincidental a steering Figure A1 four-wheel steering the front of the car, rear deflection rule 3. Four-wheel steering car components and working characteristics 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 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 different, working principle and control methods vary. The typical electric 4ws system mainly by the front wheel steering system, sensors, ECU, rear wheel steering actuators and rear wheel steering transmission mechanism etc. the sensor will front wheel steering motor sports the signal and the signal into ECU were analyzed and calculated, will process after the drive signal to rear wheel steering actuators, rear wheel steering actuators action, through the rear wheel steering transmission mechanism, rear wheel deflection. Meanwhile, ECU when carried out monitoring car operation condition, calculate target steering Angle and rear real-time steering Angle, the difference in value between real-time adjustment to rear wheels corner. Such, can according to the actual sports car, to realize the state car four-wheel steering. General 4ws cars equipped with two turning mode, can enter 4ws state, also can keep the traditional 2ws state, drivers can pass the driving indoor steering mode switch selection. When 4ws car in the course of driving the electronic control system malfunction, rear wheel automatic back into the middle, the automatic into the front wheel steering state, ensure like ordinary front wheel steering car driving safely as automobiles. Meanwhile, dashboard 4ws indicator, warning drivers, stored on ECU fault condition of warranty, so that by yards. 4. Four-wheel steering control of the car 4ws system not 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 manipulation stability as a starting point, explore due to rear brought car in response to changes, and 4 adopts various rear wheel control strategy and produce different effect. Auto four-wheel steering control depends on tires were lateral force, four-wheel steering can make cars in turn, the rear directly involved in for car yawing movement and lateralizing control. Through timely, accurate control of the rear wheel steering Angle, not only can shorten the process of steering the transient response, and can actively control cars the trajectory and attitude. In turn, that the car during its longitudinal direction centerline of the direction, even with the direction of the car horn decreases overlap, attitude Angle of steering bodywork cornering, improves the lateral stability car. 4.1 control goals That car in turn to basic keep PianJiao zero gravity side car. So can greatly improve the car to the steering 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 certain 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 request. 4.2 control strategy model based 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 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 equation with the hypothesis, but due to the above reasons, make the design of control system doesnt meet practical needs, there is no guarantee that the vehicle steering control stability. 4.3 control method Different cars driving performance requirements of steering and different 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 4ws with car on the control method basically has: (a). The set than simply steering system 4ws. (b). Than before, rear wheel steering front-wheel corner function 4ws system. (c).Than before, rear wheel steering j speed function 4ws system is. (d). The 4ws with first-order lagging system. (e).With reversed-phase characteristics 4ws system (f). With optimal control characteristics of 4ws system. (g). Has since learning, white the ability to adjust the 4ws system. Former five kinds of control system belong to classical control theory category, only to satisfy car under certain conditions, but also cant adapt to the need of motor sports of 5 random changes, along with the computer technology and some advanced control theory of development, 4ws system will towards adaptive, intelligent direction. 4.4 4ws system control technology development At present, for research 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 made 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 very lack, 4ws technology not really into wide use in commercial car on stage, no widely used. In the technology in relatively mature 4ws cars, most use electric hydraulic power 4ws system. With the rapid development of electronic technology, computer 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, as the core technical problems 4ws system - 4ws system controller design, what on earth as the best control objectives? Adopt what kind of control method? Still no in this field is the same view. Already, early before of the 4ws and the system based on a simple dof vehicle model, linear controller design are based on 4ws with linear dynamic equation hypothesis, PID control strategy. We know, 4ws system control mainly dependent on tires were transverse force. Early studies is the automobile tires as linear model, general 4ws control is based on the transverse force by tire wheel in proportion to the side PianJiao assumptions, this assumption just in the lateral acceleration smaller range effective. When in the lateral acceleration larger range, tire cornering characteristics of nonlinear area, will go to one side of the PianJiao tyres by transverse force in the response of the relationship of scale, and no longer the longitudinal force by tire vertical load, etc, have relations. In fact, car in turning down the street, tire basically all work in nonlinear area. At this time, garnish with linear control theory for research, appear reluctant to. 4ws vehicle handling dynamics problems is very complicated nonlinear multibody dynamics problems of the control system for 4ws research should be taken into account in the sports car, in-depth study of affecting its state response, establish simulation kinetic parameters of actual sports car mathematical model, adopt more effective control strategy. With the continuous development of control technology, some advanced modern control method has been applied in 4ws system control study, as optimal control and adaptive control, sliding mode control, robust control etc, in recent years, appeared again fuzzy control, based on artificial neural network theory, control method, etc. The study of 4ws control system from linear field gradually transition to nonlinear fields, some multi-degree-of-freedom car dynamics models have proposed 4ws, but mostly in infancy, is not mature. The future of the 6 development of the system is studied 4ws trend for mainly concentrated : (a). Further research and development of new rear wheel steering actuators and rear wheel steering transmission mechanism, improve the manipulation of steering portability, flexibility and steering Angle of accuracy. (b). For 4ws system, further development, design high performance, high precision, high sensitivity sensor, in order to correctly detection car sports signal. (c). Deep study turning the tyre during transient characteristics as the main factors, to join in the mathematic model of the system 4ws. (d). The control theory and control into method is applied to the 4ws controller study. 7 附錄 B 四輪轉向汽車的轉向特性及控制技術 摘要 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。 關鍵詞：四輪轉向；轉向特點；工作原理；控制；發(fā)展； 1.引言 隨著現(xiàn)代道路交通系統(tǒng)和現(xiàn)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(xiàn)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 。 2.四輪轉向汽車的轉向特性 2.1 4ws汽車與 2ws汽車轉向過程分析 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(xiàn)轉向運動。 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。 8 2.2 4ws汽車的轉向方式 根據理論分析研究和大量路試表明，四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(xiàn)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。 (a)逆相位轉向 如 圖 B1 (a)所示，在低速行駛或者方向盤轉角較大時，前、后輪實現(xiàn)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。 (b)同相位轉向 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(xiàn)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(xiàn)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，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。 （ a）逆向位轉向 （ b）同向位轉向 圖 B1 四輪轉向汽車的前、后輪偏轉規(guī)律 3. 四輪轉向汽車的組成及工作特性 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統(tǒng)，兩者之問通過一定的方式聯(lián)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 9 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 , 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(xiàn)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(xiàn)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，儀表板上的“ 4ws”指示燈亮，警告駕駛員，故障情況被存儲在 ECU中，以 便于維修時檢碼。 圖 B2 4ws控制工作原理圖 4 四輪 轉向汽車的控制 4ws 系統(tǒng)既要實現(xiàn)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。 4.1控 制目 標 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