汽车电动助力转向系统助力特性的研究

汽车电动助力转向系统设计毕业论文本章主要介绍汽车电动助力转向系统设计的背景和意义，以及论文的目的和结构安排。

汽车转向系统是车辆控制的重要组成部分，它直接影响着驾驶员的操控感受和行车安全性。

随着科技的发展，传统的液压助力转向系统逐渐被电动助力转向系统所取代。

电动助力转向系统通过电力传动装置提供操控力，相较于液压助力转向系统具有更高的效率、更好的节能性和可靠性。

本文的目的是设计一种可靠、高效的汽车电动助力转向系统。

在研究的基础上，将重点关注系统的结构设计、控制算法优化、故障诊断等方面。

通过对系统的设计和优化，可以提高汽车的操控性和安全性。

本文结构安排如下：第二章将介绍汽车电动助力转向系统的背景与发展；第三章将详细阐述系统的设计原理与结构；第四章将重点探讨控制算法的优化与实现；第五章将研究系统的故障诊断方法与技术；最后，第六章将总结全文，并提出进一步研究的展望。

通过本文的研究和实践，相信可以为汽车电动助力转向系统的设计与优化提供一定的参考和借鉴，推动汽车技术的发展与进步。

在这一部分，我们将对汽车电动助力转向系统设计相关的文献进行综述。

我们将总结已有的研究成果，以及当前存在的问题。

具体内容}本文详细介绍了汽车电动助力转向系统设计的方法和步骤，涵盖了传感器选择、电机控制、系统优化等方面。

传感器选择在汽车电动助力转向系统设计中，选择合适的传感器是至关重要的。

传感器可以检测车轮的转向角度、转向速度以及转向力等参数，为后续的电机控制提供必要的数据支持。

常见的传感器包括转向角度传感器、转向速度传感器和转向力传感器。

在选择传感器时，需考虑其精度、响应速度和可靠性等因素，并确保其能与电机控制系统良好地配合。

电机控制在汽车电动助力转向系统中，电机控制是实现转向功能的核心部分。

电机控制系统通过接收传感器提供的数据，计算并控制电机的输出力矩，从而实现汽车的转向功能。

电机控制的关键是控制算法的设计和实现。

常见的电机控制方法有PID控制、模糊控制和神经网络控制等。

汽车电动助力转向特性分析摘要：汽车电动助力转向系统(Electric Power Steering System简称EPS)是近年来发展起来的种新型动力转向系统，具有节能、质量轻、安全、环保等一系列优点，正逐步取代传统的液压助力转向系统，成为未来汽车转向系统的发展方向，其出现并迅速成为世界汽车技术研究的热点。

汽车转向系统的发展经历了从简单的纯机械转向系统、液压助力转向系统，电控液压助力转向系统，到更为节能、操纵性能更好的电动助力转向系统这几个阶段。

本文论述了EPS的特点、工作原理、结构组成、国内外的研究现状，通过对EPS各组成部分和汽车转向系统的分析出了EPS性能评价指标，并对三种助力特性曲线的特点进行了分析和比较。

EPS系统作为今后汽车转向系统的发展方向，这给EPS带来了更加广阔的应用前景。

关键词：电动助力转向；特性；发展Electric Power Steering Characteristics were AnalyzedAbstract ：EPS is a new type of automobile steering system，which has the advantages of saving fuel，light，safety and producing less pollution. EPS is taking the place of HPS gradually and becoming the trend of steering system. It is rapidly become the hotspots in the research of automobile technology of the world.The developing process of steering system has experienced several phases from the simple Mechanical Steering System, Mechanical-Hydraulic Steering System to Electric-Hydraulic Steering System，till the Electric Power Steering System(EPS) with lower energy consumption and higher performance.The article discusses the characteristics of EPS，working principle，composition and the research status of domestic and abroad. Through the analysis of components of EPS system and the steering system, then the state function of the combination system model was deduced and the model for simulation was built in this paper. Given the EPS performance evaluation，analysis and compare the three types of assist characteristic，and then design a new type of assist curve in order to reduce the steering force which based on the parameters of a certain type of car. EPS has a great use in future.Keyword: Electric power steering Characteristic Development目录1 绪论 (1)1.1研究的目的和意义 (1)1.2国内外发展状况 (3)1.2.1国外发展状况 (3)1.2.2 国内发展状况 (4)2转向系统的概述 (6)2.1转向系统的发展过程 (6)2.1.1机械式转向系统 (6)2.1.2液压式助力转向系统(HPS) (7)2.1.3电液式助力转向系统(EHPS) (8)2.2电动助力转向系统 (10)2.2.1电动助力转向系统的结构 (10)2.2.2电动助力转向系统的工作原理 (11)2.2.3电动助力转向系统的类型 (13)2.2.4电动助力转向的关键技术 (14)2.2.5电动助力转向系统的优点 (15)3 电动助力转向系统受力与性能分析 (17)3.1电动助力转向系统受力 (17)3.2 理想转向盘力矩的研究 (18)3.3电动助力转向系统性能的主要评价指标 (19)3.3.1 转向回正能力评价 (19)3.3.2 转向轻便性评价 (19)3.3.3 转向盘中间位置操纵稳定性评价 (20)3.3.4 转向盘振动评价 (20)3.3.5 转向路感及路感强度 (21)4 电动助力转向助力特性研究 (22)4.1助力特性曲线定义 (22)4.2转向助力特性曲线设计概述 (22)4.3电动助力特性曲线类型 (23)4.3.1直线型 (24)4.3.2折线型 (25)4.3.3曲线型 (25)4.4不同助力特性曲线参数的影响 (26)5 结论与发展 (29)5.1结论 (29)5.2发展 (29)参考文献 (30)1绪论随着我国经济的持续发展，人民生活水平不断提高，汽车渐渐走入人们生活中，成为现代步伐的工具，而随着汽车保有量的增加以及由此带来的一系列问题，使得“安全、节能、环保”成为未来汽车发展的三大主题。

毕业设计（论文）外文文献翻译文献、资料中文题目：汽车电动助力转向系统的研究文献、资料英文题目：The auto electric power steering system research 文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：班级：姓名：学号：指导教师：翻译日期：2017.02.14英文原文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 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 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 thehydraulic 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 andthe 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 type vehicle 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 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 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 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.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 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 presentinvention, 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 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 whichmeasures 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 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。

第37卷第5期 2015-05(上【99】电动助力转向系统阻尼特性分析及测试方法The analysis and test method of damping characteristicsfor electric power steering system李绍松 1,2, 牛加飞 2, 于志新 2, 李连京 2, 钟博浩 2LI Shao-song1,2, NIU Jia-fei2, YU Zhi-xin2, LI Lian-jing2, ZHONG Bo-hao2(1. 长春工业大学汽车工程研究院 , 长春 130012; 2. 长春工业大学机电工程学院 , 长春 130012 摘要:电动助力转向(Electric Power Steering,EPS在提供转向助力、减轻驾驶员操纵负担的同时,也能够提高汽车转向性能和驾驶舒适性,进而提高汽车的主动安全性。

建立EPS系统仿真验证平台,分析阻尼补偿控制对汽车转向性能影响,结果表明阻尼补偿控制通过设定阻尼补偿控制系数,可改善EPS动态响应及回正性能。

提出EPS系统阻尼特性测试方法,准确获得转向系统阻尼系数,为EPS阻尼补偿控制系数的设定提供参数依据。

关键词:电动助力转向;阻尼特性;阻尼补偿系数中图分类号:U461.6 文献标识码 :A 文章编号:1009-0134(201505(上-0099-03Doi:10.3969/j.issn.1009-0134.2015.05(上.28收稿日期:2014-12-03作者简介:李绍松 (1986 -, 男 , 讲师 , 博士 , 研究方向为汽车动力学仿真与控制。

0 引言EPS 系统作为电子技术与转向系统相结合的产物, 紧扣现代汽车发展的低碳、环保、安全三大主题 [1],在提供助力、减轻驾驶员操纵负担的同时,也能够提高汽车转向性能,以其优越的性能和特点有逐步替代液压助力转向的趋势[2~4]。

EPS 系统增加了转向电机及减速机构,大幅地增加了转向系统的阻尼,这给驾驶员转向过程中带来了更大的“ 粘滞” 感觉,这种感觉的强弱可以通过对转向助力电机施加阻尼补偿力矩来调整 [5]。

汽车电动助力转向(EPS)的研究发表时间：2019-07-01T13:27:12.453Z 来源：《新材料.新装饰》2018年10月下作者：王建坡[导读] 转向系统是汽车的主要子系统之一，近年来，汽车电动助力转向系统（简称为“EPS”）已成为现代汽车中的常规配置，是一种直接依靠电机提供辅助扭矩的动力转向系统。

其性能直接关系到汽车的操纵舒适性和稳定性，对安全行车、减少交通事故、保护驾驶员的人身安全以及改善驾驶员的工作条件起着重要作用。

（长城汽车股份有限公司，河北省汽车工程技术研究中心，河北保定 071000）摘要：转向系统是汽车的主要子系统之一，近年来，汽车电动助力转向系统（简称为“EPS”）已成为现代汽车中的常规配置，是一种直接依靠电机提供辅助扭矩的动力转向系统。

其性能直接关系到汽车的操纵舒适性和稳定性，对安全行车、减少交通事故、保护驾驶员的人身安全以及改善驾驶员的工作条件起着重要作用。

关键词：电动助力转向系统；特点；类型；工作原理；关键技术Vibration mechanism of transmission gear and method of modification, vibration reduction and noise reduction Wang jian poGreat Wall Motor Company,Automotive Engineering Technical Center of HeBei,baoding Abstract：Steering system is one of the main subsystems of automobiles. In recent years, electric power steering system (EPS) has become a conventional configuration in modern automobiles. It is a power steering system that directly relies on motor to provide auxiliary torque. Its performance is directly related to the comfort and stability of vehicle operation, and plays an important role in driving safety, reducing traffic accidents, protecting driver's personal safety and improving driver's working conditions. in Key words：Electric Power Steering System; Characteristics; Types; Working Principle; Key Technologies1电动助力转向系统的特点1.1电动助力转向系统与传统的液压助力转向系统相比具有的优点（1）可降低发动机能耗。

1 引言1.1 汽车电动助力转向系统的特点由于动力转向系统具有转向操纵灵活、轻便、并可吸收路面对前轮产生的冲击等优点，自20世纪50年代以来在各国汽车上开始普遍应用。

现今液压助力转向器(HPS)是以内燃机作为动力的汽车助力转向器的主流。

但是传统的HPS需要持续的能量消耗，降低了汽车的燃油经济性。

同时其复杂的液压系统具有助力特性不可调整、污染环境、维修不便等缺点。

20世纪80年代开始研究的汽车上电能为动力的电动助力转向系统(EPS)。

和HPS相比，它具有更为突出的优点:1.EPS能在各种行驶工况下提供最佳助力，减少由路面不平所引起的对转向系统的扰动，改善汽车的转向特性，减少汽车低速行驶时的转向操纵力，提高汽车高速行驶时的转向稳定性，进而提高汽车的主动安全性。

并且可通过设置不同的转向手力特性来满足不同对象使用的需要。

2.提高了汽车的燃油经济性。

液压动力转向系统需要发动机带动液压油泵，使液压油不停地流动，浪费了部分能量。

相反电动转向系的EPS需要转向操作时才需要电机提供的能量，是真正的―按需供能型‖(on demand)系统。

装有电动转向系统的车辆和装有液压助力转向系统的车辆对比实验表明，在不转向情况下、装有电动转向系统的车辆燃油消耗降低2.5%;在使用转向情况下，燃油消耗降低了5.5% 。

]1[3.增强了转向跟随性。

在EPS中，电动机与助力机构直接相连以使其能量直接用于车轮的转向。

这样增加了系统的转动惯量，电机部分的阻尼也使得车轮的反转和转向前轮摆振大大减小。

因此转向系统的抗扰动能力大大增强。

和HPS相比，旋转力矩产生于电机，没有液压助力系统的转向迟滞效应，增强了转向车轮对转向盘的跟随性能。

4.该系统由电动机直接提供转向助力，在停车时，也可获得最大的转向动力。

同时省去了液压动力转向系统所必需的动力转向油泵、软管、液压油、密封件、传送带和装于发动机上的皮带轮等，其零件比HPS大大减少，因而其质量更轻、结构更紧凑，在安装位置的选择方面也更容易，装配自动化程度更高，维修更简单。

汽车电动助力转向系统优化随着汽车工业的不断发展，汽车的操控性和安全性越来越受到人们的关注。

电动助力转向系统作为汽车转向系统的重要组成部分，其性能的优劣直接影响着驾驶者的驾驶体验和行车安全。

因此，对汽车电动助力转向系统进行优化具有重要的现实意义。

一、汽车电动助力转向系统的工作原理汽车电动助力转向系统主要由转矩传感器、车速传感器、电子控制单元（ECU）、电动机和减速机构等组成。

当驾驶者转动方向盘时，转矩传感器会检测到转向转矩的大小和方向，并将其转化为电信号传递给 ECU。

车速传感器则会检测车辆的行驶速度，并将车速信号传递给 ECU。

ECU 根据接收到的转矩信号和车速信号，计算出所需的助力转矩，并控制电动机输出相应的转矩，通过减速机构施加到转向机构上，从而实现助力转向。

二、汽车电动助力转向系统优化的必要性1、提高驾驶舒适性优化后的电动助力转向系统可以根据车速和转向转矩的变化，提供更加平滑和舒适的助力，减少驾驶者在转向过程中的疲劳感。

2、增强操控稳定性通过精确的控制策略，优化后的系统能够在高速行驶时提供适当的阻尼，提高车辆的直线行驶稳定性；在低速行驶时提供较大的助力，使转向更加轻便灵活，增强车辆的操控性。

3、降低能耗高效的电动助力转向系统可以在满足助力需求的前提下，降低电动机的能耗，提高能源利用率，延长车辆的续航里程。

4、适应多样化的驾驶需求不同驾驶者对转向助力的需求可能存在差异，优化系统可以提供多种助力模式供选择，满足个性化的驾驶需求。

三、汽车电动助力转向系统优化的关键技术1、传感器技术高精度的转矩传感器和车速传感器是实现精确助力控制的基础。

优化传感器的测量精度、响应速度和可靠性，可以提高系统的性能。

2、控制算法控制算法是电动助力转向系统的核心。

先进的控制算法如模糊控制、神经网络控制等，可以更好地处理复杂的非线性系统，实现更加精准的助力控制。

3、电动机技术选择高效、低噪音、高扭矩的电动机，并优化其驱动电路和控制策略，能够提高系统的助力性能和可靠性。

河北科技大学毕业论文题目：汽车电动助力转向系统特点与应用专业：汽车检测与维修目录引言…………………………………………………………………………………第1章汽车动力转向系统的历史发展概况……………………………………第2章汽车动力转向系统的原理及特点………………………………………第3章EPS系统的组成原理及分类……………………………………………3.1 EPS系统的组成……………………………………………………3.2 EPS系统的工作原理………………………………………………3.3 EPS系统主要部件的结构及工作原理……………………………3.4 EPS系统的分类……………………………………………………3.5 EPS系统的性能及特点……………………………………………第4章 EPS系统的发展趋势……………………………………………………引言近年来，随着电子技术的迅速发展，电子技术在汽车上的应用范围不断扩大。

汽车转向系统中愈来愈多的采用电子器件，汽车转向系统已从简单的纯机械式转向系统、液压动力转向系统（HydraulicPowerSteering，简称HPS）、电动液压助力转向系统（ElectricHydraulicPowerSteering，简称EHPS）和电控液压助力转向系统（ElecticallControlledHydraulicPowerSteering,简称ECHPS）发展到如今的更为节能及操纵性能更为优越的电动助力转向系统（ElectricalPow erSteering，简称EPS系统）。

EHPS和ECHPS系统等助力系统在汽车上的采用，改善了汽车转向力的控制特性，降低了驾驶员的转向负担，然而汽车转向系统始终处于液压机械传动阶段，EHPS相比传统HPS降低了能源损耗。

但电液动力转向系统，不论ECHPS还是EHPS都与传统的HPS一样存在液压油泄漏问题。

EPS 系统是新一代的助力转向系统，其性能特点与优势是电液动力转向系统所不能比拟的。

电动助力转向系统的研究与设计摘要电动助力转向系统(Electric Power Steering System，简称EPS)，是汽车工程领域的热门课题之一。

本文在研究了电动助力转向系统工作原理的基础上，设计开发了EPS的电子控制单元ECU (Electronic Control Unit)的硬件电路和相应的控制软件框图。

本文详细分析了电动助力转向系统电子控制单元的功能，研究开发了以89c52单片机为微处理器的电子控制单元。

控制单元具有实时数据信号采集和系统控制功能，根据采集的数据信号，确定电动机输出的目标电流，利用PWM脉宽调制技术，通过H桥式电路控制电动机的输出电流和转动方向，实现助力转向功能。

在研制了实验用ECU装置后，开发了相应的控制软件。

控制软件分为控制策略的实现和数据信号采集与分析两部分。

整个软件系统采用了模块化的设计思想。

在数据信号采集与控制部分，设计了系统主程序、A/D采集程序、车速信号采集程序和PWM控制程序。

本文所设计的EPS电子控制单元性能稳定，结构合理，与整车匹配性能好，可保证EPS实现良好的转向助力效果。

关键词：电动助力转向电子控制单元单片机控制策略Electronic power steering system Research and DesignABSTRACTElectric Power Steering System (EPS) is one of the focuses research in automotive engineering. This paper is based on the principles of EPS to study the operation, designed and developed the Electronic Control Unit (ECU) and the soft ware diagram of the ECU.The thesis Considers the functions of the electronic control unit of EPS, studied and developed the hardware that adopted 89c51as its microprocessor. The control unit was able to realize real-time data/signal acquisition and system control. The target current of motor output could be determined by the obtained data; and utilizing the Pulse-Width Modulation (PWM) technology, power could be provided to the steering system by controlling the output current and rotation direction through H-bridge circuit.The software program, which was divided into the realization of control strategy and the acquisition & control of data/signal, was developed in modular after the design of experimental ECU was completed. And the main program, A/D acquisition program, speed signal acquisition program and PWM control program are developed in the second part.The result showed that the electronic control unit designed was with stable performance, appropriate structure and excellent matching condition, and the excellent power steering effect could be ensured by EPS.Key words: Electric Power Steering System (EPS) Electronic Control Unit Single-Chip Microprocessor Control Strategy目录前言 (1)第1章绪论 (2)1.1汽车电动助力转向系统的特点 (2)1.2电动助力转向系统国内外的研究现状 (4)1.3 EPS的发展趋势和急待解决的核心技术 (5)1.4本课题研究的目的与意义 (6)第2章电动助力转向系统方案确定及工作原理 (7)2.1电动助力转向系统的工作原理 (9)2.1.1电动助力转向系统的组成和工作原理 (9)2.1.2电动助力转向系统的分类 (11)2.1.3电动助力转向系统的技术要求 (12)2.2电动助力转向系统的数学模型 (13)2.2.1转向盘和转向柱输入轴子模型 (14)2.2.2电动机模型 (14)2.2.3输出轴子模型 (16)2.2.4齿轮齿条子模型 (16)2.3电动助力转向系统的主要部分 (17)2.3.1转矩传感器 (18)2.3.2车速传感器 (19)2.3.3直流电动机 (20)2.3.4电磁离合器 (21)2.3.5减速机构 (22)2.3.6电子控制单元ECU (23)第3章电动助力转向系统的硬件设计 (24)3.1电子动力转向系统控制器的总体结构 (24)3.2控制器微处理芯片的选择 (26)3.2.1控制器微处理器常用芯片及选型 (26)3.2.2 89C52芯片及A/D转换芯片介绍 (26)3.2.3 89C52外部总线扩展及片外ROM的连接 (28)3.3控制器输入通道的设计 (30)3.3.1转矩信号的采集 (30)3.3.2电动机电流信号的采集 (31)3.3.3车速信号的采集 (33)3.4控制器输出通道的设计 (34)3.4.1电动机的PWM控制 (34)3.4.2电磁离合器和显示控制电路的设计 (39)3.4.3 电动机保护电路及继电器驱动电路设计 (40)3.5系统供电电源电路设计 (41)3.6系统硬件抗干扰措施 (42)第4章电动助力转向系统的软件设计 (45)4.1 EPS的控制策略 (45)4.1.1 EPS的PID控制 (45)4.2电子动力转向系统各功能模块的软件设计 (48)4.2.1 A/D采集程序 (48)4.2.2 PWM控制程序 (49)4.2.3车速信号采集程序 (51)4.2.4系统主程序 (53)结论 (55)谢辞 (56)参考文献 (57)附录 (59)外文资料翻译 (66)前言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。