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中南大学 译 文 原文题目:Automobile anti-lock braking system design译文题目: 汽车防抱死系统设计 学 院: 机电工程学院 专业班级: 车辆1002 学生姓名: 董镇山 学 号: 0806100714 Automobile anti-lock braking system(ABS)AbstractThis article introduced briefly the automobile anti-lock braking system(Anti-lock Braking System,is called ABS)the control principle,the control technology which used in the present automobile anti-lock braking system has carried on the summaym and has carried on the forecast to its trend of development.Key word:Automobile anti-lock braking system control technology1.outlineAlong with automobile industrys rapid development and highway unceasing construction,automobile travel security more and more takes seriously for people.To satisfy in comprehensively the brake process the automobile to the brake request,cause the brake braking force assignment to hasten reasonably.The automobile anti-lock braking system(i.e.ABS)more and more has applied on the automobile.ABSChinese translates is against deadlocks the brake system.It is one kind has the skid prevention,against to deadlock and so on merit auto safety control systems.ABS is in the convention brake system foundation advanced version technology,separable mechanical and electronic formula two kinds.On the modern automobile installs the anti-lock braking system massively,ABS both has the automobile sill to change under the stopping,guaranteed that automobiles brake yawing stability,prevented to have the side-slipping and to run,was on the present automobile is most advanced,the brake effect best arresting gear.The ordinary braking system applies the brake in the slippery road surface,or in emergency brake,because the wheel is easy the braking force to surpass the tire and the ground friction force hugs safely dies.The automobile anti-lock braking system is refers to the automobile in the brake process to be able the real-time determination wheels glide rate,the automatic control function on wheels braking moment,prevents the wheel to hug dies.Thus obtains the best brake potency the electronic installation.It can wheels glide rate control in certain scope,use fully between the tire and the road surface adhesion,reduces the stopping distance effectively,obviously enhances when the car braking controllability and stability,when each kind of traffic accident which has avoided the wheel hugs dies easy to appear.Along with brake intensitys increase,the wheel rolling ingredient are getting fewer and fewer,but skids the ingredient to be getting more and more,generally expains in the brake process with glide rate S to skid ingredient how many.The glide rate is bigger,the glide ingredient are less.And:u-wheel center speed;r-does not have time the ground braking force wheel rolling radius;w-wheels angular speed.Longitudinal and the lateral adhesion coefficient may express for the wheel slip rate is called critical point of fixity SK.Grips fast the pace according to the control theory is smaller than the SK region is called the stable brake area,wha SK later has custom-made unstable moves the area.ABS is precisely uses between the path and tires relations,compulsory wheel slid pate control nearby critical point of ficity SK,enables the toad surface adhesion property to botain the fullest display,thus achieves the best brake effect.Figure 1 coeffient of adhesion-glide rate curve At present uses ABS mainly by a round fast sensor,the electronic control unit,appendices and so on pressure control valve and group of lines,pipeline is composed.The ABS development is mainly studies the design optimization operation and the control procedure software,realizes the real-time presise brake adjustment technology,simultaneously raises hardwares level.2. Conrtol technology used by ABS nowThe ABS control effect is decided control technology4which to a great extent uses in the system.At present uses is mainly the logical threshold value control technology.To further enhance ABS the performance,but also proposed some based on the glide tate control technology,like the PID control,the glide modality change the srtucture controls,fuzzycontrol and so on.Each kind of control approaches the expectation by the different control rule the spot.2.1 PID controlsThe definition expects glide rate S0 and difference of the actual glide rate S for e=S-S0,then the PID control rule may be represented as:Therefore,the ABS controllers design sums up finally as,according to the AB S dynamic system,determined group of best arameter Kp,Ki and Kd,enable wheels glide rate to approach hypothesis goal S0 by the quickest way.2.2 The glide modality changes the structure controlAgainst holds the dead brake by the automobile basic principle to be possible to know,its brake processs essential question is wheels glide tate control in coefficient of adhesion peak point SK,then the glide modality changed structure basis system condition,the deviation and the derivative value then,in the different controlled area,by perfect switch way hand-off control quantitys size and the mark,the guarantee system in the glide region very small scope,the state point locus(S,*S)along moved the festival curve to slide slippery to the control objective(SK,0).Usually takes the braking moment for controlled variable U,the cut condition is: And Mb-,Mb+ represent the braking moment which decided by the governing system to reduce,to increase two different conditions separately. For the cut function,e=S-Sk is the actual glide rate telative target point devivation.2.3 Fuzzy controlRegarding take the glide tare as controlled members anti-lock braking system,its input value takes the expecatation glide rate and wheel actual glide tate deviation E as well as deviations rate of change EC,the output for the brake line flowing tubing head pressure.Uses the belt modification factor the fuzzy controller,uses the control list summary which the fuzzy reasoning algorithm forms is an analysis formula:And Alpha is the modification factor,Alpha the value size has reflected directly to the deviation and the debiation rate of change weighting degree.Through the adjustment modification factor Alpha,may change the control rule.When Alpha is big,indicated that is big to deviations weighting,the step response is quick,the control energy mainly uses in reducing the deviation,but easy to present the over modulation;When Alpja is small,the control goal reduces the over modulation,but the response process is slow.Usually uses the belt two Alpha values the modification factor exptessions to be able to request on the satisfiability,namely: u = X E + (1- )ECAnd,modification factor 1,2 in (0,1).2.4 Logical threshold value controlThis method establishes some control limit advance to certain controlled variable(threshold)the value,when applies the brake,according to the computation real-time parameter value and the corresponding threshold values size relations,determines wheels state of motion,thus the control adjustment brake pressure,gains enough big brake intensity and the good yawing stability.Often includes as the ABS controlled variable:Wheel skidding rate S,the wheel rotates the angle adds(reduces)the speed Omega and the rate of change. and so on three kind of descrimtion wheel movement situation or danamics condition parameter.Because only uses a controlled variable difficulty with to guarantee that ABS has the good performance under each kind of travel condition,therefore,the logical threshold value control method rotates at present the wheel the angle adds(reduce)the speed to take the primary control parameter,but takes wheel s glide tate S the secondary control parameter.And the glide rate is from each wheel fast signal after certain logic determined automobiles velocity,calculates the reference glide rate,has the difference with the actual glide rate.2.5 Double parameter controlDouble parameter controls ABS,by the vehicle speed sensor(velocity radar),a round fast sensor,the control device(computer)and the implementing agency is composed.Its principle of work is the vehicle speed sensor and a round fast sensor,separately singal input the vehicle speed and round fast the computer,calculates the actual slipping rate based on the computer,and 15% one 20% ?dose with the ideal slipping tate compares,fluctuates brakes braking force again through the solenoid valve.This kind tows the fast sensor commonly used Doppler velocity radar.When the automobile goes the Doppler radar antenna by certain frequency to the earth launching electromagnetic wave,simultaneously receives the electromagnetic wave which unceasingly reflects,surveys the automobile radar lanch and the receive differential value,then may calculate the automobile vehicle speed accurately.But turns the fast sensor to install in the transmission gearbox outer covering,acuates by the transmission gearbox output shaft,it is a pulse electrical machinery,procuces frequency and round intensive direct proportion.The impiementing agency and so on is composed of the solenoid valve and the relay.Solenoid valve adjustment braking forve,with the aim of maintaining the ideal slipping rate.This kind of ABS may guarantee that the slipping rate ideal control,against holds the braking quality to be good,but because increased a velocity radar,there the structure is complex,the cost is also high.2.6 Single parameter controlIt take controls wheels angle tetarded velocity as the object,controls wheels braking force,realizes against holds the dead brake,its structure mainly by a round fast sensor,the controller(computer)and the solenoid valve is composed.For accurate meter wheel fast,the sensing and between the wheel tooth ring should leave leeway the 1mm gap.In order to avoid the water,the putty,the dust to the sensor influence,before the installment,should the sensor replenishment butter.The solenoid valve uses in wheel brakes pressure control.Regarding four channel braking system,a vehicle rim has a solenoid valve;Three channel braking system,each front wheel has one,two two trailing wheels use in common one.The solenoid valve has three hydraulic pressure holes,separately applies the brake with the brake master cylinder and the wheel to divide the cylinder to be connected the brake with the brake master cylinder and the wheel to divide the cylinder to be connected,and can realize pressure lifting,pressure maintenance,the pressure drop accent to press the function.The principle of work is as follows:1)Pressure-rise when the solenoid valve does not work,the brake master cylinder connection and applies the brake to divide the cylinder connection respectively to go nonstop.Because the main spring intensity is big,makes charging valve openning,the brake pressure to increase.2)pressure maintenance,when wheels brake divides in cylinders pressure grows to certain value,charging valve cut-off closure.The support maintains at the compound state,three panels seal,maintain the brake pressures mutually.3)voltage dropping,when the solenoid valve works,the support overcomes two springs tension,opens the discharge meat to cause to apply the brake to divide cylinder presure drop.Once the pressure reduces,the solenoid valve transformes to the pressure maintenance condition,or pressure-rise ready condition.The control device ECU primary mission is the signal which passes on various wheels sensor carries on the computation,the analysis,the enlargement and the distintion,outputs again from thc output stagc thc command signal thc solcnoid valvc,carrics out thc brac pressure adjustment task.The electronic control,by four major part is composed,input level A,conteoller B,output stage C,constant voltage and protective device D.Electronic controller by 4101tz frequency actuation solenoid valves,this is the polot is unable to achieve.This kind of single parameter control mode ABS,because the structure is simple,the cost is low,thereforce the present use is broad.Mostly has provided this kind of single parameter control mode ABS in the American Chrysler custom car.Tt is loaded with a round fast sensor on passenger vehicles four wheels.The installment has 45 teeth or 100 tooths tooth rings on the axle tree,turns a fast sensors sending attite to go against in the tooth ring.When the wheel totates,causes the sensor to produce the voltage siglae unceasingly,and input the computer,the ideal speed compares with RoM,figures out wheels speed-up or the deceleration,issues pressure-rise or the release of pressure instruction to the solenoid valve,controls applies the brake to divide the cylinder braking force.3.The problems by used the ABS system(1)replaces the brake or the replacement hydraulic pressure braking system part,should arrange only in brake line air,in order to avoid influence braking systems normal work.(2)is loaded with the ABS automobile,every year should replace a brake fluid.Otherwise,the brake fluid water absorbability is very strong,after the watery,not only will reduce the boiling point will have the corrosion, will also create the brake potency decline.3)inspects the ABS anti-lock braking system to cramp out the power source frrst.4.Trend of developmentUses the logical threshold value control algorithm may avoid a series of numerous and diverse theoretical analysis and to some element of certainty quota measurement. Simplified controllers design because moreover on1y need determine wheels angular speed is advantageous realizes therefore the load cost is low. This algor hm already drew close maturely for current automobile ABS system universal usebut it by no means best control algorithm. Because under the different state of roads each kind of threshold value and guarantees presses the time is the empirical value which obtains after the repeated test does not have the very explicit theory basistherefore the ABS developments cycle is longand the control quality guaranteed with difficulty.Easy to realize the stepless control based on the glide rate control algorithmand has the very explicit theory to instructbut present restricts the cost question which its development the bottleneck is mainly realizes believed according to ours research om now on ABS control algorithm development direction in the following several aspects.(1) aims at current widely uses the logical threshold value control algorithm which exists the research can track the road surface characteristic changecauses the ABS each performanceindex to be at the optimum condition throughout the control algorithm. And the predictive control technology is worth taking seriously. Because when the brake process iction characteristic between the tire and the road surface causes the anti-lock braking system has the very obvious misalignmentthe denaturation and the uncertainty. Therefore difficulty with establishes its precise mathematical modelbut the predictive control has the basic characteristic which the forecast model the undle optimize and feed back adjust may act according to some optimized target design control systemdetermined that a control quantity the time seriesafter causing in period of time to move the quantity and the process will soften between the expectation paths eor to be smallest in the future. What because this algorithm uses is the online trundle optimizes unceasingly and unceasingly carries on the feedback in the optimal process through the actual system output and the forecast model outputs eor to adjust can therefore overcome to a certain extent as a result of the forecast model eor and certainuncertainty disturbance and so on influence enables systems robustness to obtain the enhancement.)1s smaller along with the volume the price is cheaper the reliable higher vehicle speedsensors appearance in the ABS system will increase the vehicle speed sensor to become possible the defmite wheel slip rate will become is accurate and is fast. And the non-contact types vehicle speed sensor (for example electro-optical type Doppler and so on) the present willmost have the possibility to apply in the automobile ABS system. This time may take seriously based on the glide rate control algorithm. And the fuzzy control will not rely on the object by the mathematical model is advantageous uses persons experience knowledge robustness is good simple practical and so on characteristics but widely will be used.)Changes the multi-objectives by the sole ABS control objective integrated control 10appeared not only the force of action control system (TCS) can prevent the wheel in the brake process to occur hugs dies moreover can in the actuation process (be specially in processes and so on state acceleration curve) prevents the driving gear to have the slipping causes automobiles in actuation process yawing stability to change the operation ability and the pick-up and so on also has the enhancement.1n the future automobile electronic control system toward om multi-electronic control unit (ECU) the scatlered independent con 01 to the sole ECU complete bikes control realizes data sharing and the integrated control direction by thenetwork way develops; Or develops to the dynamic hierarchical control direction namely each dispersion con 01 systems ECU is not on1y the respective independence constructs own dlamic compensator moreover must establish a high-level d lamic synchronizer to helpunified again to determine each ECU the control policy strengthens each ECU the control when the solution dispersion control system existence unstable mold cannot use dynamic dispersion control calm question 1enables the complete bikes overall performance to obtain the guarantee.5 SummaryThe automobi1e anti-lock braking system S) can enhance the automobile in the low coefficient of adhesion or changes under the coefficient of adhesion road surface condition the braking quality At present the ABS control technology mainly uses the logical threshold value control method but along with vehicle speed sensor technology develop ment based on wheel slip rate each kind of control algorithm by widespread value and use. Moreover. 1n the future the automobile electronic control technology and the equipment will realize the resource sharing andthe integrated control by the network way and toward the multi-objective integrated controls enhances the system performance cost ratio the direction to develop.汽车防抱死制动系统(ABS)摘 要本文简要介绍了汽车防抱死制动系统(Anti-lock Braking System,简称ABS)的控制原理,对目前汽车防抱死制动系统采用的控制技术进行了综述,并对其发展趋势进行了预测。关键词:汽车;防抱死制动系统;控制技术1 概述随着汽车工业的迅猛发展和高速公路的不断修建,汽车的行驶安全性越来越为人们重视。为了全面满足制动过程中汽车对制动的要求,使制动器制动力分配更趋合理。清楚防抱死制动系统(简称ABS)已越来越多地应用在汽车上。“ABS”中文译为“防锁死刹车系统”。他是一种具有防滑、防锁死等优点的汽车安全控制系统。ABS是常规刹车装置基础上的改进型技术,可分为机械式和电子式两种。现在汽车上大量安装防抱死制动系统,ABS既有普通制动系统的制动功能,又能防止车轮锁死,使汽车在制动状态下仍能转向,保证汽车的制动方向稳定性,防止产生侧滑和跑偏,是目前汽车上最先进、制动效果最佳的制动装置。普通制动系统在湿滑路面上制动,或在紧急制动的时候,车轮容易因制动力超过轮胎与地面的摩擦力而完全抱死。清楚防抱死制动系统是指汽车在制动过程中能实时判定车轮的滑移率,自动调节作用在车轮上的制动力矩,防止车轮抱死。从而获得最佳制动效能的电子装置。它能把车轮的滑移率控制在一定的范围之内,充分地利用轮胎与路面之间的附着力,有效地缩短制动距离,显著地提高车辆制动时的可操纵性和稳定性,从而避免了车轮抱死时易出现的各种交通事故。随着制动强度增加,车轮滚动成分越来越少,而滑移成分越来越多,一般用滑移S来说明制动过程中滑移成分的多少。滑移率越大,滑移成分越少。 其中:u车轮中心的速度;r没有地面制动力时的车轮滚动半径;w车轮的角速度。纵向和侧向附着系数课表达为车轮滑移率的函数(如图1)。最大的纵向附着系数所对应的滑移率称为临街稳定点SK。根据控制理论吧滑移率小语SK 的区域称为稳定最大区,SK以后的为非稳定稳定去。ABS正是利用道路与轮胎之间的关系,强制性地把车轮滑移率控制在临街稳定点SK附近,使路面附着性能得到最充分的发挥,从而达到最佳的制动效果。目前所采用的ABS主要有轮速传感器,电子控制单元,压力控制阀和线束、管路等附件组成。ABS的开发主要是研究设计优化运算和控制程序软件,实现实时精确的控制调节的技术,同时提高硬件的水平。2 目前ABS所采用的控制技术ABS的控制效果很大程度上取决于系统所采用的控制技术4。目前所采用的主要是逻辑门限控制技术。为进一步提高ABS的性能,还提出了一些基于滑移率的控制技术,如PID控制,滑移模态变结构控制,模糊控制等。每种控制均以不同的控制规律逼近期望的点。2.1PID控制定义期望滑移率S0与实际滑移率S之差为控制误差e=S-S0,则PID的控制规
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