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1、中南大学毕业设计英文译文 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 c
2、ontrol 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 d
3、evelopment 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(
4、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,separabl
5、e 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 au
6、tomobile 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 brak
7、ing 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
8、 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 intensit
9、ys 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 ha
10、ve 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 sta
11、ble 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 e
12、ffect.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 cont
13、rol 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
14、 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 rul
15、e 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 an
16、d 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
17、 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 st
18、ate 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 con
19、ditions 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
20、 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
21、 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 th
22、e 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,mo
23、dification 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,
24、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 t
25、hree 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 whe
26、el 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 th
27、e 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 singa
28、l 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 r
29、adar.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
30、 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
31、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 comp
32、lex,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
33、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 c
34、hannel 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 cylin
35、der 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
36、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 gr
37、ows 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 d
38、ivide 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 enlargeme
39、nt 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
40、 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
41、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 sigl
42、ae 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 sys
43、tem(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
44、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 avoi
45、d 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 c
46、urrent 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 basistheref
47、ore 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 re
48、alizes 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
