中英文文献翻译-汽车电动助力转向系统发展综述

Steering system is necessary in vehicle system is the basic system, driver through the steering wheel to manipulate and control car's direction of travel, so as to realize the intention of his driving.For more than 100 years, automobile industry with mechanical and electronic technology development and progress. Today, the car is not purely mechanical sense of a car, it is the mechanical, electronic, materials and other comprehensive product. Steering system with the development of the car industry after the long evolution.The traditional steering system is mechanical steering system, automotive steering wheel, by pilot control through such a series of mechanical parts steering wheel to realize the deflection, so as to realize the steering.As in the 1950s, hydraulic power steering system in automotive applications, marked the beginning of steering system. Sources of power steering by previous human to human and hydraulic booster.Hydraulic booster HPS (Hydraulic Power Steering) is in the Steering system based on the mechanical and Hydraulic system increased a. The hydraulic system and the engine, when the general part of the engine starts, provide automobile engine power forward, another part of the kinetic energy of hydraulic system for power. Due to its reliable work, mature technology still has been widely used. The steering system of the main characteristic is the fluid pressure, reduce drivers support in the steering wheel, improved the steering light and auto operation stability.But at the same time, there are also some hydraulic power system flaw:Aiming at vehicle design and manufacture, after the completion of the vehicle steering dynamical characteristics cannot change. The direct consequence is that when the dynamical characteristics in low power, car in low segment can get very good, but in high-speed period has good way to sense, because cannot adjust dynamical characteristics, no better way drivers, When the dynamical characteristics in high power, not very good at low segment tprompt effect,If not, aiming to vehicle hydraulic system must also be in the engine driving. As a result, the energy consumption, increase fuel engine,Existing hydraulic oil leakage problems should not only to environmental pollution, and easy to other components,Aiming at low temperatures, hydraulic system performance is poor.In recent years, with the electronic technology in the wide application, steering system also more and more used electronic devices. Turn into the electronic control system, therefore, the corresponding appeared electrohydraulic power steering system. Electrohydraulic Power Steering can be divided into two categories: electric Hydraulic Steering system (Electro Hydraulic Power - the EHPS) and electric Hydraulic Steering Electronically Contro lled ECHPS Steering (Hydraulic Power Steering). Electric hydraulic steering system is in hydraulic power system on the basis of the development of hydraulic booster systems, and different is, electric hydraulic power system ofpower sources in the hydraulic system, but not by motor engine motor drive hydraulic system, save energy and reduce the engine fuel consumption. Electric hydraulic steering is in traditional hydraulic booster systems on the basis of the development, the difference is that the electric hydraulic steering system, electronic control devices increased. The electronic control unit can according to the steering rate, speed auto operation parameters of hydraulic system, change the size of the hydraulic booster at different speeds, so as to realize the change, dynamical characteristics. But under the motor drive hydraulic system, in turn, motor can stop turning, thereby reducing energy consumption.Although electrohydraulic power steering system of hydraulic steering overcomes the drawbacks. But due to the existence of hydraulic system, it exists the hydraulic oil leakage problem, and electrohydraulic power steering system, introduced motor drive system is more complex, costs and reliability.In order to avoid Electric hydraulic Steering system, Electric Power Steering system of Electric Power Steering (EPS) should now. It with all sorts of steering system, the biggest difference lies in the electric power steering system has no hydraulic system. Originally produced by hydraulic steering system by motor. Electric power steering system of general by the torque sensor and microprocessor, motor, etc. The basic principle is: when the driver turned the steering wheel drive shaft rotation, to install in the rotation axes of the torque sensor and torque signal into electrical signals to microprocessors, microprocessor based on speed and torque signal other vehicles running parameters, according to the set procedures in the treatment of that power motors booster direction and the size of the booster. Since 1988, the first in Japan suzuki Cervo car to equip the steering system, power steering system is widely recognized by the people.Steering system is mainly embodied in the following aspects:A power steering system can provide different at different speeds under the dynamical characteristics. In the low road, steering, to increase more light, At high speed reduced steering, even in order to improve the road are increased to damp.A power steering system only in steering motors to work, to provide power, so as to reduce energy consumption.A motor, so by battery-powered electric power steering system can not work in engine under the condition of the work.Electric power steering system should not hydraulic system, compared with hydraulic booster systems and automated assembly. And electric power steering system can change the booster program microprocessor algorithm, easy dynamical characteristics of the change.The development of science and technology is changing, the traditional steering system of steering control (wheel steering), and turn of transmission mechanism. But the thought of the spark can always bring surprise! Electronic Steering system SBW Steering (to the Wire) was changed to the traditional concept of three most with micro-controller, it was replaced By the Steering transmission mechanism, the three most into two parts. Electronic steering system is the most advanced and automotive steering system of technology. It mainly consists of steering controlmodule, to execute module and micro controller three modules.Steering control module's main function is to torque sensor detection by the driver intention, and to detect signal (including rotation direction and rotational speed, etc) by bus to micro controller, and micro controller based on the signal, and speed feedback control module is a steering wheel to make drivers, can feel road. But this is the way, is the development of virtual according to test data of integrated, formed "experience", and by way of curing process in the form of micro controller. So it is with speed, turning to the size of the torque rate and some corresponding relation.Steering Angle sensor and actuator including steering motors, steering motor controller etc. It is the function of micro controller based on the control command, drive motor rotation Angle to execute, complete to action. Also the size of the rotation Angle sensor monitoring and feedback to micro controller, forming a complete accurate closed-loop control system, steering movement.Micro controller is the core of electronic steering system. It is receiving signal detection, processed send corresponding control signal.Due to the micro controller replaced steering transmission mechanism, thus mechanical connection between components of the system, reduce the response speed and the accuracy of the response. And to turn strategy, transmission control software programming any Settings, And other equipment, such as ABS, automatic navigation equipment. Transmission mechanism of reducing brings a bigger car interior space, give rides more fun. And turning behavior can be recorded, save in software that can help EEPROM after further perfecting the steering control strategy, even can provide evidence for the traffic accident.Auto safety question has been the focus of public attention. Steering system and lighting system can give at night traffic better security. Page shown above, the traditional lighting system is the vehicle to the front line irradiation, vehicles and pedestrians in corners if drivers will be hard to find in the corner, pedestrians traffic accidents. If the lighting system combined with the steering system, pictured above, when drivers in the steering wheel to the right of the steering wheel Angle, light with the right to change, the more wide illumination turn, lighting, so in a broader range of pedestrian road corner will easily be found. Currently the lighting technology has in the midrange Citroen triumph, Toyota camrys are used.At present, electronic steering system reliability and the cost is obstructed the development. If the micro controller is mainly manifested in the problem, steering system will complete failure, its not like electric power steering system and electric hydraulic steering system, in the motor or hydraulic system, also can appear when problems with human to control cars. The micro-controller electronic steering system malfunction, because no mechanical systems can be connected to the steering wheel and steering, therefore impossible to control of the car. But despite the electronic steering system is still the future development direction of steering system.Modern automotive steering device design trendAuto 1.1 high-speed needFrom the manipulation of light, the stability and security of Angle, automobile manufacturing widely used more advanced technology, using high rigidity, steering gear ratios steering. "Ratios and high rigidity is currently the world production of steering structure.Fully considering safety, 1.2 portabilityAuto speed increase, with the driver and passenger's safety is very important in many cars at home and abroad, has generally add energy absorption devices, such as safety steering belt prevent collisions, etc, the airbag, and gradually popularized. From the point of view of human engineering, manipulation of light has gradually adopts adjustable steering column and power steering system.130 low cost, low fuel consumption, specialized production quantitiesWith the international economic situation, oil crisis recession, auto production seriously more and more economical, therefore, to design the low cost, low fuel consumption, low cost, auto production line, realizing mass rationalization of specialized production. To spare parts manufacturing, especially the steering gear production, more outstanding.The computerized 1.4 automobile redirector deviceThe steering gear device, car on the way to the development of computers.2 the modern automobile steering device development trendThe modern automobile steering device 2.1 using dynamicAlong with the rapid development of the automotive industry, steering device structure has great changes. Automobile redirector structure from the prevalence of currently used, the main products are: there are four types of worm shaw (reference), worm wheel (WR type), circulation ball type (BS type) and rack-and-pinion (RP). These four redirector, has been widely used in the bus.As we have learned, in the world scope, auto cycle ball type redirector 45%, rack-and-pinion steering wheel around 40%, worm around 10% of steering gear, other types of steering 5%. Ball type redirector cycle has been steady development. In Western Europe in the passenger, rack-and-pinion steering have very big development. Japan is characteristic of automobile redirector circular ball type redirector proportion is more and more big, the Japanese equipment of different types of each type of automobile engine, using different type redirector, used in the bus cycle of ball type redirector, already from the 1960s, the development of modern 62.5% 100% (worm wheel steering gear-component on the bus has been eliminated. Large and small trucks are mostly using circular ball type redirector rack-and-pinion steering gear, but also the development. Mini vans with circular ball type redirector 65%, rack-and-pinion 35%.The comprehensive use of varieties of products, the following conclusions:Ball type redirector. Circulation rack-and pinion steering gear-component with, has become the world's two major automobile redirector, And worm # 0; Worm and worm type redirector shaw, steering gear-component is eliminated or retain smaller status.In view of the development of steering gear passenger is different, the United States and Japan focus on developing circular ball type redirector, ratio have reached or more than 90%, Western development is key rack-and pinion steering gear-component ratio, more than 50%, France has 95%.Rack-and pinion steering gear-component with the advantages of small car in the application (including passenger and freight station wagon or small) development by leaps and bounds, And large vehicles to cycle for the main structure of the ball type redirector.Ball type redirector 2.2 cycleThe ball type redirector. Circulation characteristics are: high efficiency, manipulation of light, a smooth control force characteristic curve.Decorate convenient..... Especially suitable for large and medium-sized vehicles and power steering system with, Easy to transfer the signal, High efficiency, return good thrust hydraulic booster device, and the actions as well.To realize the ratios, satisfy the requirements of manipulating portability. Intermediate position to force is small, and often used to sensitive, therefore, request to intermediate position near the small, in order to improve the sensitivity ratio. Large Angle to position, but use to resistance, so fewer to large Angle position, speed to reduce to force. Due to the circulation ball type redirector can realize ratios, increasingly wide application.Through a lot of steel rolling, contact to deliver to force, has the strength and good wear resistance. And the steering gear can be designed with etc, it is the mechanical structure is one of the reasons for its wide application.V ariable structure has higher than, the stiffness, especially suitable for high speed of vehicles. High-speed vehicles in high-speed need a better stability, must ensure to high stiffness steering.J gap is adjustable. Rack tooth fan can readjust vice wear after the clearance, make have appropriate steering gear transmission gap, so as to improve the life, but also the steering gear steering the advantages.The steering gear production in China, in addition to the early worm XieFangPai automobile production; # 0, Wheel steering gear-component with worm shaw, dongfeng automobile steering gear-component, other most models using circular ball type structure, and has certain production experience. Currently, dongfeng in active development cycle, and has the ball type redirector in second HuanXing widely used on the ball type redirector. Thus, our products to mass production cycle is in the ball type redirector development.230 redirector specialized productionCycle in foreign ball type redirector realized the specialized production, and to train and test and research to greatly improve the quality and yield of products. In Japanese seiko "(NSK) company in circular ball type redirector of low cost and good quality, yield, the Japanese market, and gradually to the sales of its products. German ZF company also as a large steering gear train. It from 1948 to start production of various type redirector, ZF steering 200 million. Some larger steering gear manufacturer, as the United States SAGINA W branch company, Delphi British BURM# 0, AN company is the professional manufacturer, has large production and sales. Specialization has become a trend, only walk this path, to make high quality products, production, low cost, in the market competitive.2.4 power steering is the direction of developmentPower steering system applied widely, not only in the heavy bus must equip, applied in the limousine car, medium or more in the application and popularization. Gradually, Mainly from reduce pilot fatigue, improve the manipulation of light and stability. Although bring higher cost and structure is complex issues, but due to the obvious advantages, or get fast development.Power steering are three forms: integral, half nged and united valve type power steeringstructure. Now three forms, rapid development, the integral front axle load 3 ~ used car, 8t front axle load of valves used in 5 # 0; 18t cars, more than half of front axle load division for the author to car. Above super-heavyFrom the development trend, abroad is developing fast, but integral steering gear integral redirector interim valve structure is the direction of development.。

附录General electric steering development at home and abroadSince the 1980s abroad in bus vigorously develop electric steering (EPS), has made considerable achievements in light, small cars, van widely used car, and every year with 300 million speed. With the plough in 2000 changhe automobile electric steering gear, van car installation in China's automobile redirector uncovers a new page in history. Due to its advantages of the steering clearly, is well received by customers welcome. First assembly of 200 electric steering trial car were soon snapped up. This years are increased production of installed electric steering car this year will reach SanWanLiuQianTai. Because the first domestic cars in the plough installed electric steering, drive the domestic electric steering develop these. To now had 10 colleges and 10 state-owned and private enterprises developing project or alone is expected to every year this product in China with 10 to 20 million speed development. Because of various aspects of electric to the study of investment, this product has come close to success, there have been some goods start loading test. In the auto electric steering product development embodies the characteristics of China's market economy competition, some colleges and enterprises, state, combine together, the private enterprise to battle the result of competition all aspects of accelerated development progress.Electric steering so called "precise steering", which is in automotive steering process, the steering gear according to different speeds, steering wheel rotation and screw accurate offers all kinds of driving the best conditions, this is steering in computer (ECU) control to realize. Electric steering gear is under computer control of electric current implementation of the size of the change control, the realization of different steering. So it can accurately realize people at different speeds, predefined turning Angle need different steering.The development of the electric steering is mainly for hydraulic steering solve pure the biggest problem, a high speed FaPiao steering wheel, which is a big problem for the vehicle steering stability. Hydraulic steering although solved the vehicle steering light sexual problems, but a high speed, steering wheel is too light it caused a pilot FaPiao feeling. New steering pump although can achieve high speed steering pump flow can be decreased, but a high speed does not guarantee the engines driving in high speed rotating pump also workingconditions. So can't completely solve the problem FaPiao car at high speed. Electric steering system can control power motors, reduce a high speed increases to hand power steering, FaPiao problems and solve high-speed, and relatively low cost. But because of the motor power, torque and size limit, so many small cars and van for light car. With the new electric steering structure research and development, the future will gradually extended to senior cars and trucks. Due to the existing outfit electric steering gear market, future potential market also relatively broad; The steering gear with low cost and popular by auto makers will.国内外电动转向发展概况国外20 世纪80 年代以来在汽车上大力发展电动转向（EPS），已经取得相当大的成果，在轻微型轿车、厢式车上得到广泛的应用，并且每年以300 万台的速度发展。

本文摘于《Race Car Vehicle Dynamics》作者：William F. Miliken and Douglas L. MilikenSteering systemsIntroductionThis chapter begins with a discussion of steering geometry—casterangle ,trail ,kingpin inclination ,and scrub radius .The next section discuss Ackermann geometry followed by steering racks and gears .Ride steer (bump steer ) and roll steer are closely related to each other ;without compliance they would be thesame .Finally ,wheel alignment is discussed .this chapter is tied to chapter 17 on suspension geometry –when designing a new chassis ,steering and suspension geometry considerations are high priorities .19.1 steering geometryThe kingpin in a solid front axle is the steering pivot .In modern independent suspensions , introduced by Maurice olley at Cadillac in 1932,the kingpin is replaced by two (or more ) ball joints that define the steering axis .This axis is not vertical or centered on the tire contact patch for a number of reason .see figure 19.1 to clarify how kingpin location is measured .In front view ,the angle is called kingpin inclination and the offset of the steering axis from the center of the tire print measured along the ground is called scrub (or scrub radius ). The distance from the kingpin axis to the wheel center plane , measured horizontally at axle height ,is the spindle length .In side view the kingpin angle is called caster angle ; if the kingpin axis does not pass through the wheel center then side view kingpin offset is present ,as in most motorcycle front ends .The distance measured on the ground from the steering axis to the center of the tire print is the trail (called caster offset in ref .1 )Kingpin front view geometryAs mentioned in chapter 17, kingpin inclination ,spindle length ,and scrub are usually a compromise between packaging and performance requirements .Some factors to consider include :1.With a positive spindle length (virtually every car is positive as shown in figure 19.1) the car will be raised up as the wheels are steered away from center .The more the kingpin inclination is tilted from vertical the more the car will be raised when the front wheels are steered .This effect always raises the car , regardless of which direction the wheel is steered ,unless the kingpin inclination is truevertical .the effect is symmetric side to side only if there is no caster angle .See the following section on caster angle .For a given kingpin inclination ,a longer positive spindle length will increase the amount of lift with steer .2.The effect of kingpin inclination and spindle length in raising the front end ,by itself ,is to aid centering of the steering at low speed .At high speed any trail will probably swamp out the effect that raise ad fall have on centering .3. Kingpin inclination affects the steer –camber characteristic .when a wheel is steered ,it will lean out at the top ,toward positive camber ,if the kingpin is inclined in the normal direction (toward the center of the car at the upper end ). Positive camber results for both left– and right-hand steer .the amount of this effect is small ,but significant if the track includes tight turns.4. When a wheel is rolling over a bumpy road ,the rolling radius is constantly changing ,resulting in changes of wheel rotation speed . This gives rise to longitudinal forces at the wheel center .The reaction of these forces will introduce kickback into the steering in proportion to the spindle length .If the spindle length is zero then there will be no kick from this source .Design changes made in the last model of the GM “P ”car (fiero ) shortened the spindle length and this resulted in less wheel kickback on rough roads when compared to early model “P ”cars.5. The scrub radius shown in figure 19.1 is negative ,as used on front-wheel–drive cars (see below ) . driving or braking forces (at the ground ) introduce steer torques proportional to the scrub radius . If the driving or braking force is different on left and right wheels then there will be a net steering torque felt by the driver (assuming that the steering gear has good enough rev erse efficiency ).The only time that this is not true is with zero scrub (centerpoint steering ) because there is no moment arm for the drive (or brake ) force to generate torque about the kingpin .With very wide tires the tire forces often are not centered in the wheel center plane due to slight changes in camber ,road surface irregularities ,tire nonuniformity (conicity ),or other asymmetric effects .These asymmetries can cause steering kickback regardless of the front view geometry .Packaging requirements often conflict with centerpoint steering and many race cars operate more or less okay on smooth tracks with large amounts of scrub .6. For front drive ,a negative scrub radius has two strong stabilizingeffects :first ,fixed steering wheel –if one drive wheel loses traction ,the opposingwheel will toe –out an amount determined by the steer compliance in the system .This will tend to steer the car in a straight line ,even though the tractive force is not equal side-to –side and the unequal tractive force is applying a yaw moment to the vehicle .Second ,with good reverse efficiency the driver’s hands never truly fix the steering wheel . In this case the steering wheel may be turned by the effect of uneven longitudinal tractive forces ,increasing the stabilizing effect of the negative scrub radius .Under braking the same is true .Negative scrub radius tends to keep the car traveling straight even when the braking force is not equal on the left and right side front tiresome (due to differences in the roadway or the brakes).Caster angle and trailWith mechanical trail ,shown in figure 19.1,the tire print follows behind the steering axis in side view .Perhaps the simplest example is on an office chair caster–with any distance of travel ,the wheel aligns itself behind the point .More trail means that the tire side force has a large moment arm to act on the kingpin axis .This produces more self-centering effect and is the primary source of self-centering moment about the kingpin axis at speed .Some considerations for choosing the caster angle and trail are :1.More trail will give higher steering force .with all cars ,less trail will lower the steering force .In some cases ,manual steering can be used on heavy sedans (instead of power steering ) if the trail is reduced to almost zero .2.Caster angle ,like kingpin inclination ,cause the wheel to rise and fall with steer .unlike kingpin inclination ,the effect is opposite from side to side .With symmetric geometry (including equal positive caster on left and right wheels ) ,the effect of left steer is to roll the car to the right ,causing a diagonal weight shift .In this case ,more load will be carried on the LF –RR diagonal ,an oversteer effect in aleft-hand turn .The diagonal weight shift will be larger if stiffer springing is used because this is a geometric effect .The distance each wheel rises (or falls ) is constant but the weight jacking and chassis roll angle are functions of the front and rear roll stiffness. This diagonal load change can be measured with the car on scales and alignment ( weaver ) plates .Keep in mind that the front wheels are not steered very much in actual racing , except on the very tightest hairpin turns . For example , on a 100-ft .radius (a 40-50 mph turn ), a 10-ft. wheelbase neutral steer car needs only about 0.1rad .(5.7)of steer at the front wheels (with a 16:1steering ratio this is about 90degree at the steering wheel ).For cars that turn in one direction only , caster stagger (differences in left and right caster ) is used to cause the car to pull to one side due to the car seeking the lowest ride height . caster stagger will also affect the diagonal weight jacking effect mentioned above .If the caster is opposite (positive on one side and negative the same number of degrees on the other side ) then the front of the car will only rise and fall with steer ,no diagonal weight jacking will occur .3. Caster angle affects steer-camber but ,unlike kingpin inclination ,the effect is favorable . With positive caster angle the outside wheel will camber in a negative direction (top of the wheel toward the center of the car ) while the inside wheel cambers in a positive direction , again learning into the turn .In skid recovery , “opposite lock ” (steer out of the turn ) is used and in this case the steer–camber resulting from caster angle is in the “wrong ” direction for increased front tire grip . conveniently ,this condition results from very low lateral force at the rear so large amounts of front grip are not needed .4. As discussed in chapter 2, tires have pneumatic trail which effectively adds to (and at high slip Angles subtracts from ) the mechanical trail . This tire effect is nonlinear with lateral force and affects steering torque and driver feel .In particular , the fact that pneumatic trail approaches zero as the tire reaches the limit will result in lowering the self-centering torque and can be s signal to the driver that the tire is near breakaway .The pneumatic trail “breakaway signal” will be swamped out by mechanical trail if the mechanical trail is large compared to the pneumatic trail .5.Sometimes the trail is measured in a direction perpendicular to the steering axis (rather than horizontal as shown in figure 19.1) because this more accurately describes the lever (moment ) arm that connects the tire lateral forces to the kingpin . Tie rod locationNote that in figure 19.1 a shaded area is shown for the steering tie rod location . Camber compliance under lateral force is unavoidable and if the tie rod is located as noted ,the effect on the steering will be in the understeer ( steer out of the turn ) direction becomes much more complex than can be covered here .19.2 Ackerman steering geometryAs the front wheels of a vehicle are steered away from the straight-ahead position ,the design of the steering linkage will determine if the wheels stay parallel or if one wheel steers more than the other .This difference in steer Angles on the left and right wheels should not be confused with toe-in or toe-out which are adjustments and add to ( or subtract from ) Ackerman geometric effects .For low lateral acceleration usage (street cars) it is common to use Ackerman geometry . as seen on the left of figure 19.2, this geometry ensures that all the wheels roll freely with no slip Angles because the wheels are steered to track a common turn center . Note that at low speed all wheels are on a significantly different radius , the inside front wheel must steer more than the outer front wheel . A reasonable approximation to this geometry may be as shown in figure 19.3.According to ref .99, Rudolf Ackerman patented the double pivot steering system in 1817 and in 1878, Charles Jeantaud added the concept mentioned above to eliminate wheel scrubbing when cornering . Another reason for Ackermann geometry ,mentioned by Maurice olley , was to keep carriage wheels from upsetting smooth gravel driveways .High lateral accelerations change the picture considerably . Now the tires alloperate at significant slip Angles and the loads on the inside track are less than on the outside track . Looking back to the tire performance curves ,it is seen that less slip angle is required at lighter loads to reach the peak of the cornering force to a higher slip angle than required for maximum side force . Dragging the inside tire along at high slip Angles ( above for peak lateral force ) raise the tire temperature and slows the car down due to slip angle ( induced ) drag .For racing , it is common to use parallel steering or even reverse Ackermann as shown on the center and right side of figure 19.2.It is possible to calculate the correct amount of reverse Ackermann if the tire properties and loads are known . In most cases the resulting geometry is found to be too extreme because the car must also be driven (or pushed ) at low speeds , for example in the pits .Another point to remember is that most turns in racing have a fairly large radius and the Ackermann effect is very small . In fact , unless the steering system and suspension are very stiff ,compliance (deflection ) under cornering loads may steer the wheels more than any Ackermann (or reverse Ackermann ) built into the geometry .The simplest construction that generates Ackermannn geometry is shown in figure 19.3 fo r “rear steer ” . Here ,the rack (cross link or relay rod in steering box systems ) is located behind the front axle and lines staring at the kingpin axis , extended through the outer tie rod ends , intersect in the center of the rear axle . The angularity of the steering knuckle will cause the inner wheel to steer more than the outer (toe-out on turning ) and a good approximation of “perfect Ackermann ” will be achieved .The second way to design-in differences between inner and outer steer Angles is by moving the rack (or cross link ) forward or backward so that it is no longer on a line directly connecting the two outer tie rod ball joints .This is shown in figure 19.4. with “rear steer ” , as shown in the figure ,moving the rack forward will tend mo re toward parallel steer (and eventually reverse Ackermann ), and moving it toward the rear of the car will increase the toe-out on turning .A third way to generate toe with steering is simply to make the steering arms different lengths . A shorter steering arm (as measured from the kingpin axis to the outer tie rod end ) will be steered through a larger angle than one with a longer knuckle. Of course this effect is asymmetric and applies only to cars turning in one direction—oval track cars .RecommendationWith the conflicting requirements mentioned above , the authors feel that parallel steer or a bit of reverse Ackermann is a reasonable compromise . With parallel steer , the car will be somewhat difficult to push through the pits because the front wheels will be fighting each other . at racing speeds , on large-radius turns , the front wheels are steered very little , thus any ackermann effects will not have a large effect on the individual wheel slip angles , relative to a reference steer angle , measured at the centerline of the car .文献翻译摘自《Race Car Vehicle Dynamics》第19章转向系统序言：本章以转向几何参数的讨论为开始，包括主销后倾角，后倾拖距，主销内倾角，主销偏置量。

汽车转向系统概述摘要本文简述了汽车转向系统在国内外的发展，经历了机械转向、液压助力转向、电控液压助力转向、电动助力转向系统四个阶段的发展的汽车转向系统已经相对成熟，探讨了汽车转向系统的发展趋势。

提出了通过控制信号解决方向盘与转向轴之间的联系问题，省略去方向盘与转向轴的机械连接装置，使汽车转向有更好的灵活性，更好的稳定性，轻便省力，并发现了系统中不够成熟和有待解决的问题。

关键词：助力转向；液压助力转向；电动助力转向AbstractThis article describes the steering system's development at home and abroad. The steering system experienced a mechanical steering, hydraulic power steering, electric hydraulic power steering and electric power steering four stages. Automotive steering system has been relatively mature. And the article explores the steering system trends. It proposed by the steering wheel and shift control signals to resolve the linkage between the axes, omitted to steering wheel and steering shaft of the mechanical connection device. It can make the car turn better flexibility, better stability. And I found that the system is not mature enough and the problems to be solved.Key Words: power steering; hydraulic power steering；electric power steering引言汽车转向系统的发展经历了传统的机械转向、液压助力转向、电控液压助力转向、电动助力转向系统四个阶段。

DSP-based电力辅助转向使用无刷直流电机MURUGAN NANDAKUMAR R,S和M S MOHIYADEENBharat Electronics Limited, Nandambakkam, Chennai 600 089e-mail: muruganr@bel.co.in; nandakumars@bel.co.in;mohiyadeenms@bel.co.in本文介绍了电的设计方法和步骤辅助动力转向系统(简称EAS)用无刷直流电机为一辆汽车。

控制建筑由两层控制,即车辆速度相关的控制以及扭矩协助控制。

在更高的层次上控制系统的体系结构、功能的车辆作为援助速度控制器、液位控制器的控制力。

在较低的水平,给出了转矩控制器的努力水平的控制。

这已经是实现了由扭矩传感器和车辆在DSP这种传感器。

为实现在系统中,DSP-based三相逆变器直流无刷电动机控制器模块是特意使用采用霍尔传感器反馈和一个单一的dc-link电流传感器。

这项工作是实现光商用车拥有一个循环球式齿轮。

这是第一次(简称EAS)的实施为这种类型的车辆在任何地方在世界上。

一般来说,有离合器递归断开电动机在高速度或非正常条件下从齿轮箱。

在该实现电动机直接耦合到变速箱没有离合器和所有的人异常处理的处理器。

这是执行,不修改车辆供应系统,比如改变现有的交流发电机或额定值电池,利用现有的传感器。

设计是这样一种方式的那种感觉司机援助可以变换轻易地在任何时间。

控制的性能实验结果表明,系统是它被测试在其中的轻型商用车辆(LCV)。

关键词。

无刷直流电机；EAS；转向系统。

1.介绍动力转向系统的转向努力降低车辆的使用外部的源,来协助将轮子。

现在大多数新一代车辆动力转向,由于车辆的趋势,走向更大质量和更宽的轮胎,所有增加的控制力所需要的。

现代交通工具很难动作,速度较低(例如当停车场)如果没有人帮助。

大多数助力转向系统工作,用皮带驱动泵提供的液压系统。

该液压压力泵,是所产生的车辆的引擎驱动。

汽车电动助力转向系统的发展汽车电动助力转向系统（Electric Power Steering，EPS）是一种利用电动机驱动的辅助转向系统，通过电子控制单元（ECU）对电动机进行控制，以提供相应的转向力。

相比传统液压助力转向系统，EPS系统具有更快的反应速度、更高的能效和更好的可调性。

本文将从EPS系统的发展历程、工作原理和优势等方面来探讨汽车电动助力转向系统的发展。

汽车电动助力转向系统最早可以追溯到20世纪70年代，当时主要是为了提高驾驶舒适性而引入的。

而随着电子技术和电动机技术的不断发展，EPS系统逐渐成为了汽车领域的研究热点。

特别是在21世纪初，EPS系统开始逐渐取代液压助力转向系统，成为了新一代汽车助力转向系统的主流。

汽车电动助力转向系统主要由电动助力转向机构、电子控制单元（ECU）、转向传感器和转向力传感器等组成。

在转向过程中，车辆的转向操作通过转向传感器转化为电信号，经过ECU处理后，输出给电动助力转向机构，电动助力转向机构则产生相应的转向力。

整个过程实现了驾驶员的转向意图和车辆的实际转向行为之间的转换。

与传统液压助力转向系统相比，汽车电动助力转向系统具有以下优势。

EPS系统可以根据驾驶员的需求提供不同的转向力，提高了转向的稳定性和可调性。

EPS系统通过电子控制单元对电机进行精确控制，使得转向更加精准和灵活。

EPS系统没有液压助力转向系统的泄漏和污染问题，更加环保和可靠。

EPS系统由于采用了电动机，能够根据车速的不同自动调整转向力的大小，提高了能效。

EPS系统的响应速度更快，可以在瞬间提供所需的转向力。

随着汽车技术和电子技术的发展，EPS系统也在不断演进和更新。

目前，EPS系统已经可以实现自适应转向力调节、主动防侧移、纠偏保持和自动泊车等功能。

还有一些新的技术在不断应用于EPS系统中，例如电磁轮边转向系统、无杆电动助力转向系统和双电机电动助力转向系统等。

汽车电动助力转向系统是汽车发展的一个重要方向，具有更好的转向稳定性、可靠性和能效。

汽车电动助力转向系统中英文对照外文翻译文献(文档含英文原文和中文翻译)原文：The auto electric power steering system researchAlong with automobile electronic technology swift and violent development, the people also day by day enhance to the motor turning handling quality request. The motor turning system hanged, the hydraulic pressure boost from the traditional machinery changes (Hydraulic Power Steering, is called HPS), the electrically controlled hydraulic pressure boost changes (Electronic Hydraulic Power Steering, is called EHPS), develops the electrically operated boost steering system (Electronic Power Steering, is called EPS), finally also will transit to the line controls the steering system (Steer By Wire, will be called SBW).The machinery steering system is refers by pilot's physical strength achievement changes the energy, in which all power transmission all is mechanical, the automobile changes the movement is operates the steering wheel by the pilot, transmits through the diverter and a series of members changes the wheel to realize. The mechanical steering system by changes the control mechanism, the diverter and major part changes the gearing 3 to be composed.Usually may divide into according to the mechanical diverter form: The gear rack type, follows round the world -like, the worm bearing adjuster hoop type, the worm bearing adjusterrefers sells the type. Is the gear rack type and follows using the broadest two kinds round the world -like (uses in needing time big steering force).In follows round the world -like in the diverter, the input changes the circle and the output steering arm pivot angle is proportional; In the gear rack type diverter, the input changes the turn and the output rack displacement is proportional. Follows round the world -like the diverter because is the rolling friction form, thus the transmission efficiency is very high, the ease of operation also the service life are long, moreover bearing capacity, therefore widely applies on the truck. The gear rack type diverter with follows round the world -like compares, the most major characteristic is the rigidity is big, the structure compact weight is light, also the cost is low. Because this way passes on easily by the wheel the reacting force to the steering wheel, therefore has to the pavement behavior response keen merit, but simultaneously also easy to have phenomena and so on goon and oscillation, also its load bearing efficiency relative weak, therefore mainly applies on the compact car and the pickup truck, at present the majority of low end passenger vehicle uses is the gear rack type machinery steering system.Along with the vehicles carrying capacity increase as well as the people to the vehicles handling quality request enhancement, the simple mechanical type steering system were already unable to meet the needs, the power steering system arise at the historic moment, it could rotate the steering wheel while the pilot to provide the boost, the power steering system divides into the hydraulic pressure steering system and the electrically operated steering system 2kinds.Hydraulic pressure steering system is at present uses the most widespread steering system.The hydraulic pressure steering system increased the hydraulic system in the mechanical system foundation, including hydraulic pump, V shape band pulley, drill tubing, feed installment, boost installment and control valve. It with the aid of in the motor car engine power actuation hydraulic pump, the air compressor and the generator and so on, by the fluid strength, the physical strength or the electric power increases the pilot to operate the strength which the front wheel changes, enables the pilot to be possible nimbly to operate motor turning facilely, reduced the labor intensity, enhanced the travel security.The hydraulic pressure boost steering system from invented already had about half century history to the present, might say was one kind of more perfect system, because its work reliable, the technology mature still widely is applied until now. It takes the power supply by the hydraulic pump, after oil pipe-line control valves to power hydraulic cylinder feed, through the connecting rod impetus rotation gear movement, may changes the boost through the change cylinder bore and the flowing tubing head pressure size the size, from this achieved changes the boost the function. The traditional hydraulic pressure type power steering system may divide into generally according to the liquid flow form: Ordinary flow type and atmospheric pressure type 2 kind of types, also may divide into according to the control valve form transfers the valve type and the slide-valve type.Along with hydraulic pressure power steering system on automobile daily popularization, the people to operates when the portability and the road feeling request also day by day enhance, however the hydraulic pressure power steering system has many shortcomings actually: ①Because its itself structure had decided it is unable to guarantee vehicles rotates the steering wheel when any operating mode, all has the ideal operation stability, namely is unable simultaneously to guarantee time the low speed changes the portability and the high speed time operation stability;②The automobile changes the characteristic to drive the pilot technical the influence to be serious;③The steering ratio is fixed, causes the motor turning response characteristic along with changes and so on vehicle speed, transverse acceleration to change, the pilot must aim at the motor turning characteristic peak-to-peak value and the phase change ahead of time carries on certain operation compensation, thus controls the automobile according to its wish travel. Like this increased pilot's operation burden, also causes in the motor turning travel not to have the security hidden danger; But hereafter appeared the electrically controlled hydraulic booster system, it increases the velocity generator in the traditional hydraulic pressure power steering system foundation, enables the automobile along with the vehicle speed change automatic control force size, has to a certain extent relaxed the traditional hydraulic pressure steering system existence question.At present our country produces on the commercial vehicle and the passenger vehicle uses mostly is the electrically controlled hydraulic pressure boost steering system, it is quite mature and the application widespread steering system. Although the electrically controlled hydraulic servo alleviated the traditional hydraulic pressure from certain degree to change between the portability and the road feeling contradiction, however it did not have fundamentally to solve the HPS system existence insufficiency, along with automobile microelectronic technology development, automobile fuel oil energy conservation request as well as global initiative environmental protection, it in aspect and so on arrangement, installment, leak-proof quality, control sensitivity, energy consumption, attrition and noise insufficiencies already more and more obvious, the steering system turned towards the electrically operated boost steering system development.The electrically operated boost steering system is the present motor turning system development direction, its principle of work is: EPS system ECU after comes from the steering wheel torque sensor and the vehicle speed sensor signal carries on analysis processing, controls the electrical machinery to have the suitable boost torque, assists the pilot to complete changes the operation. In the last few years, along with the electronic technology development, reduces EPS the cost to become large scale possibly, Japan sends the car company, Mitsubishi Car company, this field car company, US's Delphi automobile system company, TRW Corporation and Germany's ZF Corporation greatly all one after another develops EPS.Mercedes2Benz Siemens Automotive Two big companies invested 65,000,000 pounds to use in developing EPS, the goal are together load a car to 2002, yearly produce 300 ten thousand sets, became the global EPS manufacturer. So far, the EPS system in the slight passenger vehicle, on the theater box typevehicle obtains the widespread application, and every year by 300 ten thousand speed development.Steering is the term applied to the collection of components, linkages, etc. which allow for a vessel (ship, boat) or vehicle (car) to follow the desired course. An exception is the case of rail transport by which rail tracks combined together with railroad switches provide the steering function.The most conventional steering arrangement is to turn the front wheels using ahand–operated steering wheel which is positioned in front of the driver, via the steering column, which may contain universal joints to allow it to deviate somewhat from a straight line. Other arrangements are sometimes found on different types of vehicles, for example, a tiller orrear–wheel steering. Tracked vehicles such as tanks usually employ differential steering — that is, the tracks are made to move at different speeds or even in opposite directions to bring about a change of course.Many modern cars use rack and pinion steering mechanisms, where the steering wheel turns the pinion gear; the pinion moves the rack, which is a sort of linear gear which meshes with the pinion, from side to side. This motion applies steering torque to the kingpins of the steered wheels via tie rods and a short lever arm called the steering arm.Older designs often use the recirculating ball mechanism, which is still found on trucks and utility vehicles. This is a variation on the older worm and sector design; the steering column turns a large screw (the "worm gear") which meshes with a sector of a gear, causing it to rotate about its axis as the worm gear is turned; an arm attached to the axis of the sector moves the pitman arm, which is connected to the steering linkage and thus steers the wheels. The recirculating ball version of this apparatus reduces the considerable friction by placing large ball bearings between the teeth of the worm and those of the screw; at either end of the apparatus the balls exit from between the two pieces into a channel internal to the box which connects them with the other end of the apparatus, thus they are "recirculated".The rack and pinion design has the advantages of a large degree of feedback and direct steering "feel"; it also does not normally have any backlash, or slack. A disadvantage is that it is not adjustable, so that when it does wear and develop lash, the only cure is replacement.The recirculating ball mechanism has the advantage of a much greater mechanical advantage, so that it was found on larger, heavier vehicles while the rack and pinion was originally limited to smaller and lighter ones; due to the almost universal adoption of power steering, however, this is no longer an important advantage, leading to the increasing use of rack and pinion on newer cars. The recirculating ball design also has a perceptible lash, or "dead spot" on center, where a minute turn of the steering wheel in either direction does not move the steering apparatus; this is easily adjustable via a screw on the end of the steering box to account for wear, but it cannot be entirely eliminated or the mechanism begins to wear very rapidly. This design is still in use in trucks andother large vehicles, where rapidity of steering and direct feel are less important than robustness, maintainability, and mechanical advantage. The much smaller degree of feedback with this design can also sometimes be an advantage; drivers of vehicles with rack and pinion steering can have their thumbs broken when a front wheel hits a bump, causing the steering wheel to kick to one side suddenly (leading to driving instructors telling students to keep their thumbs on the front of the steering wheel, rather than wrapping around the inside of the rim). This effect is even stronger with a heavy vehicle like a truck; recirculating ball steering prevents this degree of feedback, just as it prevents desirable feedback under normal circumstances.The steering linkage connecting the steering box and the wheels usually conforms to a variation of Ackermann steering geometry, to account for the fact that in a turn, the inner wheel is actually traveling a path of smaller radius than the outer wheel, so that the degree of toe suitable for driving in a straight path is not suitable for turns.As vehicles have become heavier and switched to front wheel drive, the effort to turn the steering wheel manually has increased - often to the point where major physical exertion is required. To alleviate this, auto makers have developed power steering systems. There are two types of power steering systems—hydraulic and electric/electronic. There is also ahydraulic-electric hybrid system possible.A hydraulic power steering (HPS) uses hydraulic pressure supplied by an engine-driven pump to assist the motion of turning the steering wheel. Electric power steering (EPS) is more efficient than the hydraulic power steering, since the electric power steering motor only needs to provide assist when the steering wheel is turned, whereas the hydraulic pump must run constantly. In EPS the assist level is easily tunable to the vehicle type, road speed, and even driver preference. An added benefit is the elimination of environmental hazard posed by leakage and disposal of hydraulic power steering fluid.An outgrowth of power steering is speed adjustable steering, where the steering is heavily assisted at low speed and lightly assisted at high speed. The auto makers perceive that motorists might need to make large steering inputs while manoeuvering for parking, but not while traveling at high speed. The first vehicle with this feature was the Citroën SM with its Diravi layout, although rather than altering the amount of assistance as in modern power steering systems, it altered the pressure on a centring cam which made the steering wheel try to "spring" back to the straight-ahead position. Modern speed-adjustable power steering systems reduce the pressure fed to the ram as the speed increases, giving a more direct feel. This feature is gradually becoming commonplace across all new vehicles.Four-wheel steering (or all wheel steering) is a system employed by some vehicles to increase vehicle stability while maneuvering at high speed, or to decrease turning radius at low speed.In most four-wheel steering systems, the rear wheels are steered by a computer and actuators. The rear wheels generally cannot turn as far as the Alternatively, several systems, including Delphi's Quadrasteer and the system in Honda's Prelude line, allow for the rear wheels to be steered in the opposite direction as the front wheels during low speeds. This allows the vehicle to turn in a significantly smaller radius — sometimes critical for large trucks or vehicles with trailers.Electronic power steering systemWhat it isElectrically powered steering uses an electric motor to drive either the power steering hydraulic pump or the steering linkage directly. The power steering function is therefore independent of engine speed, resulting in significant energy savings.How it works :Conventional power steering systems use an engine accessory belt to drive the pump, providing pressurized fluid that operates a piston in the power steering gear or actuator to assist the driver.In electro-hydraulic steering, one electrically powered steering concept uses a high efficiency pump driven by an electric motor. Pump speed is regulated by an electric controller to vary pump pressure and flow, providing steering efforts tailored for different driving situations. The pump can be run at low speed or shut off to provide energy savings during straight ahead driving (which is most of the time in most world markets).Direct electric steering uses an electric motor attached to the steering rack via a gear mechanism (no pump or fluid). A variety of motor types and gear drives is possible. A microprocessor controls steering dynamics and driver effort. Inputs include vehicle speed and steering, wheel torque, angular position and turning rate.Working In Detail:A "steering sensor" is located on the input shaft where it enters the gearbox housing.The steering sensor is actually two sensors in one: a "torque sensor" that converts steeringtorque input and its direction into voltage signals, and a "rotation sensor" that converts the rotation speed and direction into voltage signals. An "interface" circuit that shares the same housingconverts the signals from the torque sensor and rotation sensor into signals the control electronics can process.Inputs from the steering sensor are digested by a microprocessor control unit that also monitors input from the vehicle's speed sensor. The sensor inputs are then compared to determine how much power assist is required according to a preprogrammed "force map" in the control unit's memory. The control unit then sends out the appropriate command to the "power unit" which then supplies the electric motor with current. The motor pushes the rack to the right or left depending on which way the voltage flows (reversing the current reverses the direction the motor spins). Increasing the current to the motor increases the amount of power assist.The system has three operating modes: a "normal" control mode in which left or right power assist is provided in response to input from the steering torque and rotation sensor's inputs; a "return" control mode which is used to assist steering return after completing a turn; and a "damper" control mode that changes with vehicle speed to improve road feel and dampen kickback.If the steering wheel is turned and held in the full-lock position and steering assist reaches a maximum, the control unit reduces current to the electric motor to prevent an overload situation that might damage the motor. The control unit is also designed to protect the motor against voltage surges from a faulty alternator or charging problem.The electronic steering control unit is capable of self-diagnosing faults by monitoring the system's inputs and outputs, and the driving current of the electric motor. If a problem occurs, the control unit turns the system off by actuating a fail-safe relay in the power unit. This eliminates all power assist, causing the system to revert back to manual steering. A dash EPS warning light is also illuminated to alert the driver. To diagnose the problem, a technician jumps the terminals on the service check connector and reads out the trouble codes.Electric power steering systems promise weight reduction, fuel savings and package flexibility, at no cost penalty.Europe's high fuel prices and smaller vehicles make a fertile testbed for electric steering, a technology that promises automakers weight savings and fuel economy gains. And in a short time, electric steering will make it to the U.S., too. "It's just just a matter of time," says Aly Badawy, director of research and development for Delphi Saginaw Steering Systems in Saginaw, Mich. "The issue was cost and that's behind us now. By 2002 here in the U.S. the cost of electric power steering will absolutely be a wash over hydraulic."Today, electric and hybrid-powered vehicles (EV), including Toyota's Prius and GM's EV-1, are the perfect domain for electric steering. But by 2010, a TRW Inc. internal study estimates that one out of every three cars produced in the world will be equipped with some form of electrically-assisted steering. The Cleveland-based supplier claims its new steering systems could improve fuel economy by up to 2 mpg, while enhancing handling. There are true bottom-line benefits as well for automakers by reducing overall costs and decreasing assembly time, since there's no need for pumps, hoses and fluids.Another claimed advantage is shortened development time. For instance, a Delphi group developed E-TUNE, a ride-and-handling software package that can be run off a laptop computer. "They can take that computer and plug it in, attach it to the controller and change all the handling parameters -- effort level, returnability, damping -- on the fly," Badawy says. "It used to take months." Delphi has one OEM customer that should start low-volume production in '99.Electric steering units are normally placed in one of three positions: column-drive, pinion-drive and rack-drive. Which system will become the norm is still unclear. Short term, OEMs will choose the steering system that is easiest to integrate into an existing platform. Obviously, greater potentialcomes from designing the system into an all-new platform."We have all three designs under consideration," says Dr. Herman Strecker, group vice president of steering systems division at ZF in Schwaebisch Gmuend, Germany. "It's up to the market and OEMs which version finally will be used and manufactured.""The large manufacturers have all grabbed hold of what they consider a core technology," explains James Handysides, TRW vice president, electrically assisted steering in Sterling Heights, Mich. His company offers a portfolio of electric steering systems (hybrid electric, rack-, pinion-, and column-drive). TRW originally concentrated on what it still believes is the purest engineering solution for electric steering--the rack-drive system. The system is sometimes refered to as direct drive or ball/nut drive.Still, this winter TRW hedged its bet, forming a joint venture with LucasVarity. The British supplier received $50 million in exchange for its electric column-drive steering technology and as sets. Initial production of the column and pinion drive electric steering systems is expected to begin in Birmingham, England, in 2000."What we lack is the credibility in the steering market," says Brendan Conner, managing director, TRW/LucasVarity Electric Steering Ltd. "The combination with TRW provides us with a good opportunity for us to bridge that gap." LucasVarity currently has experimental systems on 11 different vehicle types, mostly European. TRW is currently supplying its EAS systems for Ford and Chrysler EVs in North America and for GM's new Opel Astra.In 1995, according to Delphi, traditional hydraulic power steering systems were on 7596 of all vehicles sold globally. That 37-million vehicle pool consumes about 10 million gallons in hydraulic fluid that could be superfluous, if electric steering really takes off.The present invention relates to an electrically powered drive mechamsm for providing powered assistance to a vehicle steering mechanism. According to one aspect of the present invention, there is provided an electrically powered driven mechanism for providing powered assistance to a vehicle steering mechanism having a manually rotatable member for operating the steering mechanism, the drive mechanism including a torque sensor operable to sense torque being manually applied to the rotatable member, an electrically powered drive motor drivingly connected to the rotatable member and a controller which is arranged to control the speed and direction of rotation of the drive motor in response to signals received from the torque sensor, the torque sensor including a sensor shaft adapted for connection to the rotatable member to form an extension thereof so that torque is transmitted through said sensor shaft when the rotatable member is manually rotated and a strain gauge mounted on the sensor shaft for producing a signal indicative of the amount of torque being transmitted through said shaft.Preferably the sensor shaft is non-rotatably mounted at one axial end in a first coupling member and is non-rotatably mounted at its opposite axial end in a second coupling member, the first and second coupling members being inter-engaged to permit limited rotation therebetween so that torque under a predetermined limit is transmitted by the sensor shaft only and so that torque above said predetermined limit is transmitted through the first and second coupling members.The first and second couplingmembers are preferably arranged to act as a bridge for drivingly connecting first and second portions of the rotating member to one another.Preferably the sensor shaft is of generally rectangular cross-section throughout the majority of its length.Preferably the strain gauge includes one or more SAW resonators secured to the sensor shaft.Preferably the motor is drivingly connected to the rotatable member via a clutch.Preferably the motor includes a gear box and is concentrically arranged relative to the rotatable member.Various aspects of the present invention will hereafter be described, with reference to the accompanying drawings, in which :Figure 1 is a diagrammatic view of a vehicle steering mechanism including an electrically powered drive mechanism according to the present invention,Figure 2 is a flow diagram illustrating interaction between various components of the drive mechanism shown in Figure 1 ,Figure 3 is an axial section through the drive mechanism shown in Figure 1, Figure 4 is a sectional view taken along lines IV-IV in Figure 3,Figure 5 is a more detailed exploded view of the input drives coupling shown in Figure 3, andFigure 6 is a more detailed exploded view of the clutch showing in Figure 3. Referring initially to Figure 1 , there is shown a vehicle steering mechanism 10 drivingly connected to a pair of steerable road wheels The steering mechanism 10 shown includes a rack and pinion assembly 14 connected to the road wheels 12 via joints 15. The pinion(not shown) of assembly 14 is rotatably driven by a manually rotatable member in the form of a steering column 18 which is manually rotated by a steering wheel 19.The steering column 18 includes an electric powered drive mechanism 30 which includes an electric drive motor (not shown in Figure 1) for driving the pinion in response to torque loadings in the steering column 18 in order to provide power assistance for the operative when rotating the steering wheel 19.As schematically illustrated in Figure 2, the electric powered drive mechanism includes a torque sensor20 which measures the torque applied by the steering column 18 when driving the pinion and supplies a signal to a controller 40. The controller 40 is connected to a drive motor 50 and controls the electric current supplied to the motor 50 to control the amount of torque generated by the motor 50 and the direction of its rotation.The motor 50 is drivingly connected to the steering column 18 preferably via a gear box 60, preferably an epicyclic gear box, and a clutch 70. The clutch 70 is preferably permanently engaged during normal operation and is operative under certain conditions to isolate drive from the motor 50 to enable the pinion to be driven manually through the drive mechanism 30. This is a safety feature to enable the mechanism to function in the event of the motor 50 attempting to drive the steering column too fast and/or in the wrong direction or in the case where the motor and/or gear box have seized.The torque sensor 20 is preferably an assembly including a short sensor shaft on which is mounted a strain gauge capable of accurately measuring strain in the sensor shaft brought about by the application of torque within a predetermined range.Preferably the predetermined range of torque which is measured is 0-lONm; more preferably is about l-5Nm.Preferably the range of measured torque corresponds to about 0-1000 microstrain and the construction of the sensor shaft。

附录A 外文文献Electric Power Steering system1.HistoryIn automobile development course, Steering system experienced four stages of development: from the initial mechanical Steering system (for your DNS setting Steering, abbreviation ) development for Hydraulic Steering system (Hydraulic Power Steering, abbreviation HPS), then again appeared electronically controlled Hydraulic Steering system (Electro Hydraulic Power Steering, abbreviation EHPS) and Electric Power Steering system (Steering, room Power as EPS). Assemble mechanical steering system of car parking and low-speed driving, when the driver's steering control burden too heavy, in order to solve this problem, the American GM in the 1950s took the lead in the car hydraulic steering system. But, hydraulic steering system can't juggle vehicles to speed portability and high speed, so the steering stability Koyo in Japan in 1983, with the company introduced the application of speed sensing function of hydraulic steering system. This new type of steering system can provide speed increased with the decreasing steering, but complicated structure, cost is higher, and cannot overcome hydraulic system itself has many shortcomings, is a cross between a hydraulic steering and electric power steering the transition between the products. In 1988, Japan Suzuki company first in small cars equipped with Cervo Koyo company development on the steering column, power type electric power steering system; In 1990, Japan Honda NSX in sports car company adopted self-developed rack power type electric power steering system, henceforth unveils the electric power steering in cars applications history2.Working principleElectric power steering system are as follows: first, the working principle, torque sensor measured on steering wheel drivers on the manipulation of the moment, the wheel speed sensors detect the vehicle driving speed, then present the two signals to ECU; According to the built-in control strategy: ECU, calculates the ideal target booster torque, into current instructions to motor; Then, the power generated by the torque motor slowdown institutions amplification on steering system in mechanical manipulation of the moment, and the driver together to overcome resistance torque, realize to the vehicle steering.3. Working processElectric power steering system as traditional hydraulic system alternative products has entered into the auto manufacturing. And had predicted instead, EPS not only applicable to small cars, and some for 12V medium vehicle installed electric system.EPS system includes the following components:The torque sensor: detection steering wheel motion and vehicle motion situation;Electronic control units: according to provide the torque sensor the size of the signal computing power;Motor: according to the electronic control units; turn power output value generation Reduction gear: improve motor power, and produce turn it sends to steering mechanism.Other vehicle system control algorithm input information is provided by the car CAN bus (for example steering Angle and bus speed, etc.). Motor drive also need other information, such as motor rotor position and the three-phase motor sensor (current sensor provided). Motor control by four MOSFET, due to micro controller cannot direct drive of large gate capacitance, MOSFET using drive IC form needed the interface, for safety, complete motor control system must implement monitoring, motor control system integration in PCB, usually contains a relay, the relay use, as the main switch under the condition of the fault detection, disconnect motor and electronic control units.Micro control device must control EPS system and have brushless motor. Micro control device according to the torque sensor provide needed the steering wheel torque information, forming a current control loop. In order to improve the security of the system level, the micro control device should have an on-board oscillator, so even in external oscillator malfunction case, also ensure micro control device performance, also should have chip watchdog. Infineon XC886 integration of the company all the important micro control device component, other safety features for through the software to realize, if must implement safety standards IEC61508 industries, you have to finish all kinds of diagnosis and self-inspection task and increase micro control device work load. At present different customers use of torque sensor and rotor position sensor difference is very big. They use different measuring principle, such as decomposing machine, magnetic resonance device, based on the integration of giant magnet or stance sensor.The role of power levels is switch electric current. The power level has two main functions: drive IC control and protection MOSFET, MOSFET itself and to be responsible for switch currents. MOSFET and partition.Micro control device PWM output port provides driver current and voltage is too low, can't directly connected with MOSFET screen realization. Drive IC role is to provide enough current, the grid to charge for MOSFET, so that in the and discharge 20kHz conditions, and ensure the normal realization switch for discretion side provides the high bar source voltage MOSFET, ensure that you get the low conduction resistance. If the high side MOSFET in open state, to source potential close battery level. Want to make MOSFET arrived at nominal conduction resistance, gate to higher than 8V source voltage. MOSFET completely conduction needed the most ideal voltage is required, therefore 10V or above a grid of potential than battery voltage 10V is higher. Charge pump is to ensure that the function to the largest extent reduce MOSFET power (even if low battery voltage conditions) circuit.The other key charge pump design according to different characteristics that can be PWM pattern request, achieve extremely low (low to 1%) and high rate of 390v (high to 100%). Drive IC another important function is testing, avoid damage to short-circuit mosfets, affected MOSFET will be closed, diagnosis submitted to micro control device.附录B 外文文献的中文翻译电动助力转向系统1.发展历史在汽车的发展历程中，转向系统经历了四个发展阶段：从最初的机械式转向系统（Manual Steering，简称MS）发展为液压助力转向系统（Hydraulic Power Steering，简称HPS），然后又出现了电控液压助力转向系统（Electro Hydraulic Power Steering，简称EHPS）和电动助力转向系统（Electric Power Steering，简称EPS）。

新型汽车动力转向技术发展综述摘要：转向系统是人—车交流的界面。

随着汽车技术的发展，汽车转向系统的功能也由原来单纯减轻驾驶员的驾驶疲劳转变为主动干预驾驶员转向行为，实现辅助驾驶或智能驾驶，以准确实现驾驶员的转向意图或使汽车按照理想轨迹转向。

通过分析电动助力转向系统、主动转向系统、差速助力转向系统和智能转向系统的转向原理及实现方式，获取其研究方法及技术路线，为今后各种转向系统的开发研究及性能优化奠定基础。

关键词：电动助力转向；主动转向；线控转向；差速助力转向；智能转向中图分类号：u461.4文献标文献标志码：a文献标doi：10.3969/j.issn.2095-1469.2012.06.01作为人—车交换界面的转向系统，其性能的好坏直接影响着汽车的操纵稳定性、驾驶舒适性和行驶安全性。

作为汽车研发人员，始终在为转向系统的性能改善不懈努力，希望能够使转向系统按照驾驶员的意图工作或者按照理想的转向轨迹进行主动干预。

转向系统从传统的纯机械式转向系统发展到动力转向系统，随后出现新型的主动转向系统、差速助力转向系统，一直到未来的智能转向系统，转向性能也由开始解决驾驶员的驾驶疲劳到如今的智能辅助驾驶。

虽然这些转向系统中的部分已经成功应用于实际生产，但是由于设计理念较为新颖，科研人员还在不断地对其机械结构、控制方式等进行改进设计。

因此，有必要对当今新型转向系统进行系统研究，为今后开发新型转向系统和优化性能奠定基础。

1 电动助力转向系统电动助力转向系统（electric power steering system，eps）是继液压助力转向系统后产生的一种动力转向系统，它依靠电动机提供辅助转矩，通过控制电动机电流的大小和方向，来调节电动机助力的大小和方向，从而同时满足汽车低速转向轻便性和高速转向路感的要求[1]。

电动助力转向按照助力电机的安装位置不同可分为：管柱式电动助力转向系统（column-assist type eps，ceps）、齿轮式电动助力转向系统（pinion-assist type eps，peps）、齿条式电动助力转向系统（rack-assist type eps，reps）3种结构型式[2]。

的动态特征时,以低段参数效果不是很好,如果没有,目标车辆液压系统也必须在发动机驱动。

因此,能源消耗,增加燃料发动机,现有的液压油泄漏问题应该不仅污染环境,而且容易影响其他组件。

针对低温,液压系统性能很差。

近年来,随着电子技术的广泛应用,转向系统也越来越多的使用电子设备。

因此,变成使用电子控制系统出现相应的电动液压助力转向系统。

电动液压动力转向系统可以分为两类:电动液压操舵系统(电液压动力(EHPS)和电动液压转向电子控制转向(液压动力转向)。

电动液压操舵系统在液压动力系统的基础上开发的液压增压系统,不同的是,电动液压系统液压系统的电源,但不是由汽车发动机汽车驱动液压系统,节约能源,降低发动机油耗。

电动液压操舵装置是在传统的液压助力系统的基础上开发,所不同的是,电动液压操舵系统,电子控制设备增加。

电子控制单元可以根据转向速度,速度的汽车液压系统的操作参数,改变液压增压速度不同的大小,从而实现变化,动态特征。

但根据电机驱动液压系统,反过来,电机停止转动,从而减少能源消耗。

虽然电动液压动力转向液压操舵系统克服了缺点。

但由于液压系统的存在,它的存在液压油泄漏问题,和电动液压助力转向系统,介绍了电机驱动系统更复杂,成本和可靠性。

为了区别电动液压转向系统、电动助力转向系统电动助力转向(EPS)。

现在应该知道各种各样的转向系统,最大的区别在于电动助力转向系统没有液压系统。

最初由液压操舵系统的电动机。

电动助力转向系统一般由扭矩传感器和微处理器、电机、等的基本原理是:当司机将方向盘驱动轴旋转,安装在转动轴的扭矩传感器和扭矩信号到电信号微处理器,微处理器基于其他车辆运行速度和扭矩信号的参数,根据治疗的程序集电力汽车助推器方向和大小的助推器。

自1988年以来,第一次在日本铃木Cervo汽车装备转向系统、动力转向系统被广泛承认的人。

转向系统主要体现在以下方面:动力转向系统可以提供不同在不同速度下的动态特性。

低,方向盘,增加更多的光,在高速转向减少,甚至为了提高道路增加潮湿。

附录2中文翻译汽车转向系统的发展历史及未来技术趋势屈裕丰（合肥工业大学，机械汽车工程学院）摘要：转向系统是整车系统中必不可少的最基本的组成系统，驾驶者通过方向盘来操纵和控制汽车的行进方向，从而实现自己的驾驶意图。

一百多年来，汽车工业随着机械和电子技术的发展而不断前进。

到今天，汽车已经不是单纯机械意义上的汽车了，它是机械、电子、材料等学科的综合产物。

汽车转向系统也随着汽车工业的发展历经了长时间的演变。

本文介绍了汽车转向系统的历史及未来的技术发展趋势。

关键词：转向系统；转向器；液压助力传统的汽车转向系统是机械式的转向系统，汽车的转向由驾驶员控制方向盘，通过转向器等一系列机械转向部件实现车轮的偏转，从而实现转向。

随着上世纪五十年代起，液压动力转向系统在汽车上的应用，标志着转向系统革命的开始。

汽车转向动力的来源由以前的人力转变为人力加液压助力。

液压助力系统HPS（Hydraulic Power Steering）是在机械式转向系统的基础上增加了一个液压系统而成。

该液压系统一般与发动机相连，当发动机启动的时候，一部分发动机能量提供汽车前进的动能，另外一部分则为液压系统提供动力。

由于其工作可靠、技术成熟至今仍被广泛应用。

这种助力转向系统主要的特点是液压力支持转向运动，减小驾驶者作用在方向盘上的力，改善了汽车转向的轻便性和汽车运行的稳定性行的稳定性。

但同时液压助力系统也存在一些缺点：在车辆设计制造完成后，车辆转向的助力特性不能改变。

直接后果是，当助力特性偏向于低速助力时，汽车在低速段可以得到很好的助力，但是在高速段需要有较好路感的时候，由于助力特性不能调节，使得驾驶者没有较好的路感；当助力特性偏向于高速助力时，在低速段得不到很好的助力效果；即使车辆不转向，液压系统也必须在发动机的带动下工作。

其结果是，消耗发动机能量，增加油耗；存在液压油泄漏问题，不仅对环境造成污染，而且容易使其他部件损坏；在低温下，液压系统的工作性能比较差。

汽车转向系统的历史汽车转向系统在车辆系统中是最基础的系统，驾驶员通过方向盘操纵和控制汽车的行驶方向，从而实现了他的行驶意图。

100多年里，汽车行业中机械和电子技术的发展。

如今，汽车已经不是纯粹的机械，它是机械、电子和其他材料等的综合产品。

汽车产业的转向系统的发展，经过了漫长的变革。

传统的转向系统是机械转向系统，汽车的方向盘通过试点，通过这样一系列的机械零件使方向盘实现偏转，从而实现转向的控制。

由于在20世纪50年代，液压助力转向系统在汽车上的应用，标志着转向系统又进入一个新的开始。

汽车转向系统的动力源从人力转变为液压助力转向。

转向系统增加了液压助力器，高压钠灯（液压助力转向）是基于机械和液压系统。

液压系统和发动机，发动机开始时一部分是汽车发动机的功率，另一部分的功率是液压系统的动能。

由于其工作可靠，成熟的技术已被广泛使用。

转向系统的主要特点是流体的压力，减少驾驶员在方向盘的支持，提高了转向灯和自动运行的稳定性。

但同时，也有一些液压动力系统的缺陷。

针对汽车设计和制造，完成后的车辆转向动态特性无法改变。

其直接后果是，在低功率时汽车的部分的动力特性可以得到很好的发挥，但在高速期间有良好的方式来检测，因为是不可调整的动力特性，没有更好的方式驱动，当动力学特征高功率时，而不是非常善于低段的效果好。

如果没有看准车辆的液压系统，还必须是发动机驱动。

因此，能源消耗提高燃油发动机，现有的液压油泄漏问题不仅污染环境，容易到其他组件，针对气温低，液压系统的性能较差。

近年来，随着电子技术的广泛应用，转向系统也越来越多地使用电子设备。

变成电子控制系统，因此，相应的出现了电动助力转向系统。

电液动力转向可以分为两大类：电动液压转向系统（电液压动力 - EHPS）和电动液压转向，电控ECHPS转向（液压助力转向）。

电动液压助力转向系统是在液压系统的液压助力系统的发展的基础上，不同的是，在液压系统动力源的电动液压动力系统，但不是由汽车发动机电机驱动液压系统，节约能源和减少发动机的燃料消耗。

中英文对照外文翻译Electronic power steering systemWhat it isElectrically powered steering uses an electric motor to drive either the power steering hydraulic pump or the steering linkage directly. The power steering function is therefore independent of engine speed, resulting in significant energy savings.How it works :Conventional power steering systems use an engine accessory belt to drive the pump, providing pressurized fluid that operates a piston in the power steering gear or actuator to assist the driver.In electro-hydraulic steering, one electrically powered steering concept uses a high efficiency pump driven by an electric motor. Pump speed is regulated by an electric controller to vary pump pressure and flow, providing steering efforts tailoredfor different driving situations. The pump can be run at low speed or shut off to provide energy savings during straight ahead driving (which is most of the time in most world markets).Direct electric steering uses an electric motor attached to the steering rack via a gear mechanism (no pump or fluid). A variety of motor types and gear drives is possible. A microprocessor controls steering dynamics and driver effort. Inputs include vehicle speed and steering, wheel torque, angular position and turning rate.Working In Detail:A "steering sensor" is located on the input shaft where it enters thesensor" that converts steering torque input and its direction into voltage signals, and a "rotation sensor" that converts the rotation speed and direction into voltage signals. An "interface" circuit that shares the same housing converts the signals from the torque sensor and rotation sensor into signals the control electronics can process.Inputs from the steering sensor are digested by a microprocessor control unit that also monitors input from the vehicle's speed sensor. The sensor inputs are then compared to determine how much power assist is required according to a preprogrammed "force map" in the control unit's memory. The control unit then sends out the appropriate command to the "power unit" which then supplies the electric motor with current. The motor pushes the rack to the right or left depending on which way the voltage flows (reversing the current reverses the direction the motor spins). Increasing the current to the motor increases the amount of power assist.The system has three operating modes: a "normal" control mode in which left or right power assist is provided in response to input from the steering torque and rotation sensor's inputs; a "return" control mode which is used to assist steering return after completing a turn; and a "damper" control mode that changes with vehicle speed to improve road feel and dampen kickback.If the steering wheel is turned and held in the full-lock position and steering assist reaches a maximum, the control unit reduces current to the electric motor to prevent an overload situation that might damage the motor. The control unit is also designed to protect the motor against voltage surges from a faulty alternator or charging problem.The electronic steering control unit is capable of self-diagnosing faults by monitoring the system's inputs and outputs, and the driving current of the electric motor. If a problem occurs, the control unit turns the system off by actuating a fail-safe relay in the power unit. This eliminates all power assist, causing the system to revert back to manual steering. A dash EPS warning light is also illuminated to alert the driver. To diagnose the problem, a technician jumps the terminals on the service check connector and reads out the trouble codes.click here to see a biggerElectric power steering systems promise weight reduction, fuel savings and package flexibility, at no cost penalty.Europe's high fuel prices and smaller vehicles make a fertile testbed for electric steering, a technology that promises automakers weight savings and fuel economy gains. And in a short time, electric steering will make it to the U.S., too. "It's just just a matter of time," says Aly Badawy, director of research and development for Delphi Saginaw Steering Systems in Saginaw, Mich. "The issue was cost and that's behind us now. By 2002 here in the U.S. the cost of electric power steering will absolutely be a wash over hydraulic."Today, electric and hybrid-powered vehicles (EV), including Toyota's Prius and GM's EV-1, are the perfect domain for electric steering. But by 2010, a TRW Inc. internal study estimates that one out of every three cars produced in the world will be equipped with some form of electrically-assisted steering. The Cleveland-based supplier claims its new steering systems could improve fuel economy by up to 2 mpg, while enhancing handling. There are true bottom-line benefits as well for automakers by reducing overall costs and decreasing assembly time, since there's no need for pumps, hoses and fluids.Another claimed advantage is shortened development time. For instance, a Delphi group developed E-TUNE, a ride-and-handling software package that can be run off a laptop computer. "They can take that computer and plug it in, attach it to the controller and change all the handling parameters -- effort level, returnability, damping -- on the fly," Badawy says. "It used to take months." Delphi has one OEM customer that should start low-volume production in '99.Electric steering units are normally placed in one of three positions: column-drive, pinion-drive and rack-drive. Which system will become the norm is still unclear. Short term, OEMs will choose the steering system that is easiest to integrate into an existing platform. Obviously, greater potential comes from designing the system into an all-new platform."We have all three designs under consideration," says Dr. Herman Strecker, group vice president of steering systems division at ZF in Schwaebisch Gmuend, Germany. "It's up to the market and OEMs which version finally will be used and manufactured.""The large manufacturers have all grabbed hold of what they consider a core technology," explains James Handysides, TRW vice president, electrically assisted steering in Sterling Heights, Mich. His company offers a portfolio of electric steering systems (hybrid electric, rack-, pinion-, and column-drive). TRW originally concentrated on what it still believes is the purest engineering solution for electric steering--the rack-drive system. The system is sometimes refered to as direct drive or ball/nut drive.Still, this winter TRW hedged its bet, forming a joint venture with LucasVarity. The British supplier received $50 million in exchange for its electric column-drive steering technology and as sets. Initial production of the column and pinion drive electric steering systems is expected to begin in Birmingham, England, in 2000."What we lack is the credibility in the steering market," says Brendan Conner, managing director, TRW/LucasVarity Electric Steering Ltd. "The combination with TRW provides us with a good opportunity for us to bridge that gap." LucasVarity currently has experimental systems on 11 different vehicle types, mostly European. TRW is currently supplying its EAS systems for Ford and Chrysler EVs in North America and for GM's new Opel Astra.In 1995, according to Delphi, traditional hydraulic power steering systems were on 7596 of all vehicles sold globally. That 37-million vehicle pool consumes about 10 million gallons in hydraulic fluid that could be superfluous, if electric steering really takes off.The present invention relates to an electrically powered drive mechamsm for providing powered assistance to a vehicle steering mechanism. According to one aspect of the present invention, there is provided an electrically powered driven mechanism for providing powered assistance to a vehicle steering mechanism having a manually rotatable member for operating the steering mechanism, the drive mechanism including a torque sensor operable to sense torque being manually applied to the rotatable member, an electrically powered drive motor drivingly connected to the rotatable member and a controller which is arranged to control the speed and direction of rotation of the drive motor in response to signals received from the torque sensor, the torque sensor including a sensor shaft adapted for connection to the rotatable member to form an extension thereof so that torque is transmitted throughsaid sensor shaft when the rotatable member is manually rotated and a strain gauge mounted on the sensor shaft for producing a signal indicative of the amount of torque being transmitted through said shaft.Preferably the sensor shaft is non-rotatably mounted at one axial end in a first coupling member and is non-rotatably mounted at its opposite axial end in a second coupling member, the first and second coupling members being inter-engaged to permit limited rotation therebetween so that torque under a predetermined limit is transmitted by the sensor shaft only and so that torque above said predetermined limit is transmitted through the first and second coupling members.The first and second coupling members are preferably arranged to act as a bridge for drivingly connecting first and second portions of the rotating member to one another.Preferably the sensor shaft is of generally rectangular cross-section throughout the majority of its length.Preferably the strain gauge includes one or more SAW resonators secured to the sensor shaft.Preferably the motor is drivingly connected to the rotatable member via a clutch.Preferably the motor includes a gear box and is concentrically arranged relative to the rotatable member.Various aspects of the present invention will hereafter be described, with reference to the accompanying drawings, in which :Figure 1 is a diagrammatic view of a vehicle steering mechanism including an electrically powered drive mechanism according to the present invention,Figure 2 is a flow diagram illustrating interaction between various components of the drive mechanism shown in Figure 1 ,Figure 3 is an axial section through the drive mechanism shown in Figure 1, Figure 4 is a sectional view taken along lines IV-IV in Figure 3,Figure 5 is a more detailed exploded view of the input drives coupling shown in Figure 3, andFigure 6 is a more detailed exploded view of the clutch showing in Figure 3. Referring initially to Figure 1 , there is shown a vehicle steering mechanism 10 drivingly connected to a pair of steerable road wheels The steering mechanism 10 shown includes a rack and pinion assembly 14 connected to the road wheels 12 via joints 15. The pinion(not shown) of assembly 14 is rotatably driven by a manually rotatable member in the form of a steering column 18 which is manually rotated by a steering wheel 19.The steering column 18 includes an electric powered drive mechanism 30 which includes an electric drive motor (not shown in Figure 1) for driving the pinion in response to torque loadings in the steering column 18 in order to provide power assistance for the operative when rotating the steering wheel 19.As schematically illustrated in Figure 2, the electric powered drive mechanism includes a torque sensor20 which measures the torque applied by the steering column 18 when driving the pinion and supplies a signal to a controller 40. The controller 40 is connected to a drive motor 50 and controls the electric current supplied to the motor 50 to control the amount of torque generated by the motor 50 and the direction of its rotation.The motor 50 is drivingly connected to the steering column 18 preferably via a gear box 60, preferably an epicyclic gear box, and a clutch 70. The clutch 70 is preferably permanently engaged during normal operation and is operative under certain conditions to isolate drive from the motor 50 to enable the pinion to be driven manually through the drive mechanism 30. This is a safety feature to enable the mechanism to function in the event of the motor 50 attempting to drive the steering column too fast and/or in the wrong direction or in the case where themotor and/or gear box have seized.The torque sensor 20 is preferably an assembly including a short sensor shaft on which is mounted a strain gauge capable of accurately measuring strain in the sensor shaft brought about by the application of torque within a predetermined range.Preferably the predetermined range of torque which is measured is 0-lONm; more preferably is about l-5Nm.Preferably the range of measured torque corresponds to about 0-1000 microstrain and the construction of the sensor shaft is chosen such that a torque of 5Nm will result in a twist of less than 2° in the shaft, more preferably less than 1 °.Preferably the strain gauge is a SAW resonator, a suitable SAW resonator being described in WO91/13832. Preferably a configuration similar to that shown in Figure 3 of WO91/13832 is utilised wherein twoSAW resonators are arranged at 45° to the shaft axis and at 90° to one another.Preferably the resonators operate with a resonance frequency of between 200-400 MHz and are arranged to produce a signal to the controller 40 of 1 MHz ±500 KHz depending upon the direction of rotation of the sensor shaft. Thus, when the sensor shaft is not being twisted due to the absence of torque, it produces a 1 MHz signal.When the sensor shaft is twisted in one direction it produces a signal between 1.0 to 1.5 MHz. When the sensor shaft is twisted in the opposite direction it produces a signal between 1.0 to 0.5 MHz. Thus the same sensor is able to produce a signal indicative of the degree of torque and also the direction of rotation of the sensor shaft.Preferably the amount of torque generated by the motor in response to a measured torque of between 0-10Nm is 0-40Nm and for a measured torque of between l-5Nm is 0-25Nm.Preferably a feed back circuit is provided whereby the electric current being used by the motor is measured and compared by the controller 40 to ensure that the motor is running in the correct direction and providing the desired amount of power assistance. Preferably the controller acts to reduce the measured torque to zero and so controls the motor to increase its torque output to reduce the measured torque.A vehicle speed sensor (not shown) is preferably provided which sends a signal indicative of vehicle speed to the controller. The controller uses this signal to modify the degree of power assistance provided in response to the measured torque.Thus at low vehicle speeds maximum power assistance will be provided and a high vehicle speeds minimum power assistance will be provided.The controller is preferably a logic sequencer having a field programmable gate array for example a XC 4005 as supplied by Xilinx. Such a controller does not rely upon software and so is able to function more reliably in a car vehicle environment. It is envisaged that a logic sequence not having a field programmable array may be used.Electronic power steering system (English as EPS), and hydraulic power steering system (HPS) compared to, EPS has many advantages.The advantage is that the EPS:1) high efficiency. HPS efficiency is very low, generally 60% to 70%, while EPS and electrical connections, high efficiency, and some can be as high as 90 percent.2) less energy consumption. Automobile traffic in the actual process, at the time to about 5 percent of the time travelling, the HPS system, engine running, the pumps will always be in working condition, the oil pipeline has been in circulation, so thatvehicle fuel consumption rate by 4 % To 6%, while EPS only when needed for energy, vehicle fuel consumption rates only increased by 0.5 percent.3) "Road sense of" good. Because EPS internal use of rigid, system of the lag can be controlled by software, and can be used in accordance with the operation of the driver to adjust.4) back to being good. EPS simple structure of small internal resistance, is a good back, get back to being the best characteristics, improve vehicle handling and stability.5) little environmental pollution. HPS hydraulic circuit in the hydraulic hoses and connectors, the existence of oil leaking, but hydraulic hoses can not be recovered, the environmental pollution are to a certain extent, while EPS almost no pollution to the environment.6) can be independent of the engines work. EPS for battery powered devices, as long as sufficient battery power, no matter what the condition for the engine, can produce power role.7) should have a wide range.8) easy to assemble and good layout.Now, power steering systems of some cars have become the standard-setting, the whole world about half of the cars used to power steering. With the development of automotive electronics technology, some cars have been using electric power steering gear, the car of the economy, power and mobility has improved. Electric power steering device on the car is a new power steering system device, developed rapidly in recent years both at home and abroad, because of its use of programmable electronic control devices, the flexibility in the same time there are also potential safety problems. In the analysis This unique product on the basis of the author of the characteristics of electronic control devices, security clearance just that the factors that deal with security measures, and discussed a number of concerns the safety of specific issues. The results show that : Existing standards can not meet the electric power steering device security needs and made the electric power steering device safety evaluation of the idea. Research work on the electric power steering device development and evaluation of reference value.电子动力转向系统图1电子动力转向系统的工作原理电子动力转向系统是通过一个电动机来驱动动力方向盘液压泵或直接驱动转向联动装置。

附录附录APower motor for EPS provide the power, the power source of the system is EPS, according to the instructions of the unit, and the output ECU for the aid of torque. Power motor performance in largely decided to the EPS system performance, so EPS system to motor performance requirements of the high. Compared to normal motor, electric power steering system with the motor should have the following characteristics. First of all because most vehicle power supply for 12 V dc, therefore, ask dc motor power supply electricity down and have big rated current of the rated power; and Secondly, the volume as low as possible, inertia, wide range of speed regulation of small, control characteristic, smooth operation, and low torque fluctuation little, low speed. High speed, big gear ratio will increase of mechanical system, the influence of system dynamic performance inertia; In turn blocking when can also provide power torque. For large vehicles, or even should be able to provide the opposite direction of power and rotational torque.附录B助力电机为EPS提供动力，是EPS系统的动力源，它根据ECU单元的指令，输出适宜的助力转矩。

附录附录A 英文文献Along with automobile electronic technology swift and violent development, the people also day by day enhance to the motor turning handling quality request. The motor turning system changed, the hydraulic pressure boost from the traditional machinery changes (Hydraulic Power Steering, is called HPS), the electrically controlled hydraulic pressure boost changes (Elect ric Hydraulic Power Steering, is called EHPS), develops the electrically operated boost steering system (Elect ric Power Steering, is called EPS), finally also will transit to the line controls the steering system (Steer By Wire, will be called SBW).The machinery steering system is refers by pilot's physical strength achievement changes the energy, in which all power transmission all is mechanical, the automobile changes the movement is operates the steering wheel by the pilot, transmits through the diverter and a series of members changes the wheel to realize. The mechanical steering system by changes the control mechanism, the diverter and major part changes the gearing 3 to be composed.Usually may divide into according to the mechanical diverter form: The gear rack type, follows round the world -like, the worm bearing adjuster hoop type, the worm bearing adjuster refers sells the type. Is the gear rack type and follows using the broadest two kinds round the world -like (uses in needing time big steering force).In follows round the world -like in the diverter, the input changes the circle and the output steering arm pivot angle is proportional; In the gear rack type diverter, the input changes the turn and the output rack displacement is proportional. Follows round the world -like the diverter because is the rolling friction form, thus the transmission efficiency is very high, the ease of operation also the service life are long, moreover bearing capacity, therefore widely applies on the truck. The gear rack type diverter with follows round the world -like compares, the most major characteristic is the rigidity is big, the structure compact weight is light, also the cost is low. Because this way passes on easily by the wheel the reacting force to the steering wheel, therefore has to the pavement behavior response keen merit, but simultaneously also easy to have phenomena and so on goon and oscillation, also its load bearing efficiency relativeweak, therefore mainly applies on the compact car and the pickup truck, at present the majority of low end passenger vehicle uses is the gear rack type machinery steering system.Along with the vehicles carrying capacity increase as well as the people to the vehicles handling quality request enhancement, the simple mechanical type steering system were already unable to meet the needs, the power steering system arise at the historic moment, it could rotate the steering wheel while the pilot to provide the boost, the power steering system divides into the hydraulic pressure steering system and the electrically operated steering system 2 kinds.Hydraulic pressure steering system is at present uses the most widespread steering system.The hydraulic pressure steering system increased the hydraulic system in the mechanical system foundation, including hydraulic pump, V shape band pulley, drill tubing, feed installment, boost installment and control valve. It with the aid of in the motor car engine power actuation hydraulic pump, the air compressor and the generator and so on, by the fluid strength, the physical strength or the electric power increases the pilot to operate the strength which the front wheel changes, enables the pilot to be possible nimbly to operate motor turning facilely, reduced the labor intensity, enhanced the travel security.The hydraulic pressure boost steering system from invented already had about half century history to the present, might say was one kind of more perfect system, because its work reliable, the technology mature still widely is applied until now. It takes the power supply by the hydraulic pump, after oil pipe-line control valves to power hydraulic cylinder feed, through the connecting rod impetus rotation gear movement, may changes the boost through the change cylinder bore and the flowing tubing head pressure size the size, from this achieved changes the boost the function. The traditional hydraulic pressure type power steering system may divide into generally according to the liquid flow form: Ordinary flow type and atmospheric pressure type 2 kind of types, also may divide into according to the control valve form transfers the valve type and the slide-valve type.Along with hydraulic pressure power steering system on automobile daily popularization, the people to operates when the portability and the road feeling request also day by day enhance, however the hydraulic pressure power steering system has many shortcomings actually: ①Because its itself structure had decided it is unable to guarantee vehicles rotates the steering wheel when any operating mode, all has the ideal operation stability, namely is unable simultaneously to guarantee time the low speed changes theportability and the high speed time operation stability;②The automobile changes the characteristic to drive the pilot technical the influence to be serious; ③The steering ratio is fixed, causes the motor turning response characteristic along with changes and so on vehicle speed, transverse acceleration to change, the pilot must aim at the motor turning characteristic peak-to-peak value and the phase change ahead of time carries on certain operation compensation, thus controls the automobile according to its wish travel. Like this increased pilot's operation burden, also causes in the motor turning travel not to have the security hidden danger; But hereafter appeared the electrically controlled hydraulic booster system, it increases the velocity generator in the traditional hydraulic pressure power steering system foundation, enables the automobile along with the vehicle speed change automatic control force size, has to a certain extent relaxed the traditional hydraulic pressure steering system existence question.At present our country produces on the commercial vehicle and the passenger vehicle uses mostly is the electrically controlled hydraulic pressure boost steering system, it is quite mature and the application widespread steering system. Although the electrically controlled hydraulic servo alleviated the traditional hydraulic pressure from certain degree to change between the portability and the road feeling contradiction, however it did not have fundamentally to solve the HPS system existence insufficiency, along with automobile microelectronic technology development, automobile fuel oil energy conservation request as well as global initiative environmental protection, it in aspect and so on arrangement, installment, leak-proof quality, control sensitivity, energy consumption, attrition and noise insufficiencies already more and more obvious, the steering system turned towards the electrically operated boost steering system development.The electrically operated boost steering system is the present mo tor turning system development direction, its principle of work is: EPS system ECU after comes from the steering wheel torque sensor and the vehicle speed sensor signal carries on analysis processing, controls the electrical machinery to have the suitable boost torque, assists the pilot to complete changes the operation. In the last few years, along with the electronic technology development, reduces EPS the cost to become large scale possibly, Japan sends the car company, Mitsubishi Car company, this field car company, US's Delphi automobile system company, TRW Corporation and Germany's ZF Corporation greatly all one after another develops EPS.Mercedes2Benz and Siemens Automotive two big companiesinvested 65,000,000 pounds to use in developing EPS, the goal are together load a car to 2002, yearly produce 300 ten thousand sets, became the global EPS manufacturer. So far, the EPS system in the slight passenger vehicle, on the theater box type vehicle obtains the widespread application, and every year by three million speed development.Steering is the term applied to the collection of components, linkages, etc. which allow for a vessel (ship, boat) or vehicle (car) to follow the desired course. An exception is the case of rail transport by which rail tracks combined together with railroad switches provide the steering function.The most conventional steering arrangement is to turn the front wheels using a hand–operated steering wheel which is positioned in front of the driver, via the steering column, which may contain universal joints to allow it to deviate somewhat from a straight line. Other arrangements are sometimes found on different types of vehicles, for example, a tiller or rear–wheel steering. Tracked vehicles such as tanks usually employ differential steering —that is, the tracks are made to move at different speeds or even in opposite directions to bring about a change of course.Many modern cars use rack and pinion steering mechanisms, where the steering wheel turns the pinion gear; the pinion moves the rack, which is a sort of linear gear which meshes with the pinion, from side to side. This motion applies steering torque to the kingpins of the steered wheels via tie rods and a short lever arm called the steering arm.Older designs often use the recirculating ball mechanism, which is still found on trucks and utility vehicles. This is a variation on the older worm and sector design; the steering column turns a large screw (the "worm gear") which meshes with a sector of a gear, causing it to rotate about its axis as the worm gear is turned; an arm attached to the axis of the sector moves the pitman arm, which is connected to the steering linkage and thus steers the wheels. The recirculating ball version of this apparatus reduces the considerable friction by placing large ball bearings between the teeth of the worm and those of the screw; at either end of the apparatus the balls exit from between the two pieces into a channel internal to the box which connects them with the other end of the apparatus, thus they are "recirculated".The rack and pinion design has the advantages of a large degree of feedback and direct steering "feel"; it also does not normally have any backlash, or slack. A disadvantage is that it is not adjustable, so that when it does wear and develop lash, the only cure is replacement.The recirculating ball mechanism has the advantage of a much greater mechanical advantage, so that it was found on larger, heavier vehicles while the rack and pinion was originally limited to smaller and lighter ones; due to the almost universal adoption of power steering, however, this is no longer an important advantage, leading to the increasing use of rack and pinion on newer cars. The recirculating ball design also has a perceptible lash, or "dead spot" on center, where a minute turn of the steering wheel in either direction does not move the steering apparatus; this is easily adjustable via a screw on the end of the steering box to account for wear, but it cannot be entirely eliminated or the mechanism begins to wear very rapidly. This design is still in use in trucks and other large vehicles, where rapidity of steering and direct feel are less important than robustness, maintainability, and mechanical advantage. The much smaller degree of feedback with this design can also sometimes be an advantage; drivers of vehicles with rack and pinion steering can have their thumbs broken when a front wheel hits a bump, causing the steering wheel to kick to one side suddenly (leading to driving instructors telling students to keep their thumbs on the front of the steering wheel, rather than wrapping around the inside of the rim). This effect is even stronger with a heavy vehicle like a truck; recirculating ball steering prevents this degree of feedback, just as it prevents desirable feedback under normal circumstances.The steering linkage connecting the steering box and the wheels usually conforms to a variation of Ackermann steering geometry, to account for the fact that in a turn, the inner wheel is actually traveling a path of smaller radius than the outer wheel, so that the degree of toe suitable for driving in a straight path is not suitable for turns.As vehicles have become heavier and switched to front wheel drive, the effort to turn the steering wheel manually has increased - often to the point where major physical exertion is required. To alleviate this, auto makers have developed power steering systems. There are two types of power steering systems—hydraulic and electric/electronic. There is also a hydraulic-electric hybrid system possible.A hydraulic power steering (HPS) uses hydraulic pressure supplied by an engine-driven pump to assist the motion of turning the steering wheel. Electric power steering (EPS) is more efficient than the hydraulic power steering, since the electric power steering motor only needs to provide assist when the steering wheel is turned, whereas the hydraulic pump must run constantly. In EPS the assist level is easily tunable to the vehicletype, road speed, and even driver preference. An added benefit is the elimination of environmental hazard posed by leakage and disposal of hydraulic power steering fluid.An outgrowth of power steering is speed adjustable steering, where the steering is heavily assisted at low speed and lightly assisted at high speed. The auto makers perceive that motorists might need to make large steering inputs while manoeuvering for parking, but not while traveling at high speed. The first vehicle with this feature was the Citroën SM with its Diravi layout, although rather than altering the amount of assistance as in modern power steering systems, it altered the pressure on a centring cam which made the steering wheel try to "spring" back to the straight-ahead position. Modern speed-adjustable power steering systems reduce the pressure fed to the ram as the speed increases, giving a more direct feel. This feature is gradually becoming commonplace across all new vehicles.Four-wheel steering (or all wheel steering) is a system employed by some vehicles to increase vehicle stability while maneuvering at high speed, or to decrease turning radius at low speed.In most four-wheel steering systems, the rear wheels are steered by a computer and actuators. The rear wheels generally cannot turn as far as the Alternatively, several systems, including Delphi's Quadrasteer and the system in Honda's Prelude line, allow for the rear wheels to be steered in the opposite direction as the front wheels during low speeds. This allows the vehicle to turn in a significantly smaller radius —sometimes critical for large trucks or vehicles with trailers.附录B 文献翻译随着汽车电子技术的迅猛发展,人们对汽车转向操纵性能的要求也日益提高。

电动转向助力的原理、分类及发展综述摘要：转向系统作为汽车的一个重要组成部分，其性能的好坏将直接影响到汽车的转向特性、稳定性和行驶安全性。

在国外，各大汽车公司对汽车电动助力转向系统（Electric power steering-EPS,或称Elec-tric Assisted Steering-EAS）的研究有20多年的历史。

为了解决转向系统“轻”与“灵”的矛盾[1]，采用现代控制技术和电子技术的电动助力转向系统(EPS)应运而生。

随着近年来电子控制技术的成熟和成本的降低，EPS越来越受到人们的重视，并以其具有传统动力转向系统不可比拟的优点，迅速迈向了应用领域，部分取代了传统液压动力转向系统（Hydraulic powersteering,简称HPS）。

关键词：工作原理、分类、发展1.EPS的工作原理及特点电动助力转向系统是在传统机械转向系统的基础上发展起来的。

它利用电动机产生的动力来帮助驾驶员进行转向操作，系统主要由三大部分构成，信号传感装置(包括扭矩传感器、转角传感器和车速传感器)，转向助力机构(电机、离合器、减速传动机构)及电子控制装置[2]。

电动机仅在需要助力时工作，驾驶员在操纵转向盘时，扭矩转角传感器根据输入扭矩和转向角的大小产生相应的电压信号，车速传感器检测到车速信号，控制单元根据电压和车速的信号，给出指令控制电动机运转，从而产生所需要的转向助力。

其结构示意图如图1所示。

图1 带双小齿轮的电动机机械转向助力器总体视图1.1EPS的优点1.1.1节约了能源消耗。

没有转向油泵，且电动机只是在需要转向时才接通电源，所以动力消耗和燃油消耗均可降到最低。

1.1.2对环境无污染。

该系统应用电力作为能源，消除了由于转向油泵带来的噪声污染。

也不存在液压助力转向系统中液压油的泄漏与更换而造成的污染。

同时该系统由于没有使用不可回收的聚合物组成的油管、油泵和密封件等配件，从而避免了污染。

1.1.3增强了转向跟随性。

汽车电动助力转向系统的发展汽车电动助力转向系统（Electric Power Steering, EPS）是指通过电动机替代传统的液压系统或机械系统来提供转向力的一种技术。

这一技术的发展历程可以追溯到上世纪90年代初，随着电子技术和汽车工程的发展，汽车电动助力转向系统逐渐成为现代汽车行业的重要技术之一。

在传统的液压助力转向系统中，通过液压泵将发动机输出的动力转化为液压能，再通过液压缸将液压能传递给转向机构，从而实现转向力的增幅。

这种系统的好处是转向力矩大，转向感觉清晰，但是由于液压泵和液压缸的存在，造成了系统的体积、重量和能耗都相对较大。

相比之下，汽车电动助力转向系统通过电机直接提供转向力，不需要液压液和液压泵、液压缸等液压元件，从而使得整个系统的体积和重量都大大减小，同时也降低了系统的能耗。

电动助力转向系统还可以通过改变电机的工作方式，实现不同底盘的操控特性调校，提升整车的稳定性和操控性能。

第一阶段是早期的电子助力转向系统（Electronic Power Assisted Steering, EPAS），这一阶段的电助力转向系统主要是通过电机提供转向力矩，但是由于当时电机功率和控制技术限制，转向力矩相对较小，无法满足大型车辆和高速行驶的需求。

第二阶段是中期的电动助力转向系统，通过电机的功率提升和控制技术的改进，转向力矩得到了显著增强，可以满足更多车型的需求。

为了提升操控性能，一些电动助力转向系统开始引入了转向力矩补偿和主动回馈技术，使得驾驶员可以更加清晰地感受到车辆的转向情况。

第三阶段是现代化的电动助力转向系统，随着电子技术的迅猛发展和电机技术的不断突破，电动助力转向系统在转向力矩、响应速度和稳定性方面取得了巨大的进步。

现代化的电动助力转向系统采用了多级齿轮系统，使得转向力矩更加平稳可控，同时还引入了主动力矩补偿和主动回馈技术，提升了驾驶的舒适性和操控性能。

为了满足不同车辆和驾驶条件下的需求，现代化的电动助力转向系统还可以通过电机参数的调整和控制策略的优化，实现不同操控特性的调校。

汽车转向控制中英文对照外文翻译文献(文档含英文原文和中文翻译)中英文对照翻译汽车的转向控制控制系统稳定性是针对提高驾驶安全性提出的一系列措施中最新的一个。

这个系统能够在40毫秒内实现从制动开始到制动恢复的过程，这个时间是人的反应时间得七倍。

他们通过调整汽车扭矩或者通过应用汽车左侧或右侧制动，如果需要甚至两者兼用，来实现准确的行车路线。

这个系统已被应用于奔驰S600汽车了。

稳定的机械自动系统能够在制动时发现肇端，并且在驾驶人员发现能够反应以前实现车辆的减速。

安全玻璃，安全带，撞击缓冲区，安全气囊，ABS系统，牵引力控制系统还有现在的稳定调节系统。

汽车安全系统的连续升级，已经产生了一种为保护汽车所有者安全的设计模式。

稳定调节系统帮助驾驶员从不可控制的曲线制动中解脱出来，从而避免了汽车的摆动滑行和交通事故。

利用计算机和一系列传感器，稳定调节系统能够检测到制动轮的打滑并且比人更快的恢复对汽车的方向控制。

系统每百万分之一秒作出一次快速捕捉，以及断断汽车是否在按照驾驶员的路线行驶。

如果检测到汽车行驶路线和驾驶员驾驶路线存在一个微小的偏差，系统会在瞬间纠正发动机扭矩或者应用汽车左右制动。

过程的标准反应时间是40毫秒----人的平均反应时间的七分之一。

罗伯特博世工程系统负责人安东·范·桑特解释说：“一个稳定的控制系统能够‘感觉到”驾驶员想要运动的方向，通过控制转向角度，油门踏板的位置，制动板的状态来确定汽车实际运动路线的偏航比率（汽车偏离方向轴的角度）和横向加速度”。

项目负责人阿明·马勒领导着范桑特的工作小组和奔驰汽车公司的工程师发明了第一个完全有效的稳定调节系统，该系统由发动机扭矩控制系统，制动系统，牵引控制系统组成以实现理想与现实运动之间的最小差距。

汽车安全专家相信稳定调节系统能够减少交通事故的发生，至少是在伤亡严重的事故方面。

安全统计表明，多数的单车撞击事故伤亡（占伤亡事故发生的4%），事故能够通过应用这项新技术避免。