机械毕业设计英文外文翻译467四轮转向汽车的转向特性及控制技术副本.docx

1、机械毕业设计英文外文翻译467四轮转向汽车的转向特性及控制技术 副本附录附录ASteering Behavior and Control Technology0f Fourwheel Steering AutomobiIeABSTRACTThis 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

2、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

3、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

4、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 s

5、tability and driving safety. 2. The cars steering four-wheel steering 2.1 4ws cars and 2ws steering process analysisOrdinary 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.

6、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, produced change direction, participate in the sport

7、s 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 pass

8、ive 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

9、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 pr

10、ocess of steering, high sensitivity, fast response, effectively overcome the shortcomings. 2.2 4ws automobile steering wayAccording 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 d

11、eveloped 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

12、 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 ce

13、rtain 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

14、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

15、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

16、-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 with four-wheel steering. （a）Revers

17、e a steering （b）Coincidental a steeringFigure A1 four-wheel steering the front of the car, rear deflection rule3. 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 s

18、ystem, 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 meth

19、ods 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

20、 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-tim

21、e 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, dri

22、vers 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

23、 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 stabilit

24、y. 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 adopts various rear wheel control strategy and produce different effect. Auto four-wheel s

25、teering 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 transien

26、t 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.

27、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

28、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 sys

29、tem 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 accurat

30、e. 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 performan

31、ce 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 h

32、as: (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). W

33、ith 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 random