外文翻譯-汽車防抱死系統(tǒng)設計

1、<p><b>　　譯 文</b></p><p>　　原文題目：Automobile anti-lock braking system design</p><p>　　譯文題目： 汽車防抱死系統(tǒng)設計 </p><p>　　學 院： 機電工程學院 </p>

2、;<p>　　專業(yè)班級： 機械工程及自動化09級（3）班 </p><p>　　學生姓名： xxxxxxx </p><p>　　學 號： xxxxxxxxxxxx </p><p>　　Automobile anti-lock braking syste

3、m(ABS)</p><p><b>　　Abstract</b></p><p>　　This article introduced briefly the automobile anti-lock braking system(Anti-lock Braking System,is called ABS)the control principle,the cont

4、rol 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.</p><p>　　Key word:Automobile anti-lock bra

5、king system control technology</p><p><b>　　1.outline</b></p><p>　　Along with automobile industry's rapid development and highway' unceasing construction,automobile' trave

6、l 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-lo

7、ck braking system(i.e.ABS)more and more has applied on the automobile.</p><p>　　"ABS"Chinese translates is "against deadlocks the brake system".It is one kind has the skid prevention,agai

8、nst 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.</p><p>　　On the

9、 modern automobile installs the anti-lock braking system massively,ABS both has the automobile sill to change under the stopping,guaranteed that automobile's brake yawing stability,prevented to have the side-slipping

10、 and to run,was on the present automobile is most advanced,the brake effect best arresting gear.</p><p>　　The ordinary braking system applies the brake in the slippery road surface,or in emergency brake,bec

11、ause the wheel is easy the braking force to surpass the tire and the ground friction force hugs safely dies.</p><p>　　The automobile anti-lock braking system is refers to the automobile in the brake process

12、to be able the real-time determination wheel's glide rate,the automatic control function on wheel's braking moment,prevents the wheel to hug dies.Thus obtains the best brake potency the electronic installation.It

13、 can wheel's 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 controllabi</p><p

14、>　　And:u--wheel center speed;r--does not have time the ground braking force wheel rolling radius;w--wheel's angular speed.</p><p>　　Longitudinal and the lateral adhesion coefficient may express for th

15、e 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 a

16、rea.ABS is precisely uses between the path and tire's relations,compulsory wheel slid pate control nearby critical point of ficity SK,enables the toad surface adhesion property to botain the fullest display,thus <

17、/p><p>　　Figure 1 coeffient of adhesion-glide rate curve </p><p>　　At present uses ABS mainly by a round fast sensor,the electronic control unit,appendices and so on pressure control valve and grou

18、p 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

19、hardware's level.</p><p>　　2. Conrtol technology used by ABS now</p><p>　　The ABS control effect is decided control technology[4]which to a great extent uses in the system.At present uses is

20、 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

21、 controls,fuzzycontrol and so on.Each kind of control approaches the expectation by the different control rule the spot.</p><p>　　2.1 PID controls</p><p>　　The definition expects glide rate S0

22、and difference of the actual glide rate S for e=S-S0,then the PID control rule may be represented as:</p><p>　　Therefore,the ABS controller's design sums up finally as,according to the AB S dynamic syste

23、m,determined group of best arameter Kp,Ki and Kd,enable wheel's glide rate to approach hypothesis goal S0 by the quickest way.</p><p>　　2.2 The glide modality changes the structure control</p>&l

24、t;p>　　Against holds the dead brake by the automobile basic principle to be possible to know,its brake process's essential question is wheel's glide tate control in coefficient of adhesion peak point SK,then th

25、e 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 quantity's size and the mark,the guar

26、antee system in the glide region very small scope,the state point locus(S,*S)along mo</p><p>　　Usually takes the braking moment for controlled variable U,the cut condition is:</p><p>　　And Mb-,M

27、b+ represent the braking moment which decided by the governing system to reduce,to increase two different conditions separately.</p><p>　　For the cut function,e=S-Sk is the actual glide rate telative target

28、point devivation.</p><p>　　2.3 Fuzzy control</p><p>　　Regarding take the glide tare as controlled member's anti-lock braking system,its input value takes the expecatation glide rate and whee

29、l actual glide tate deviation E as well as deviation's 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

30、 which the fuzzy reasoning algorithm forms is an analysis formula:</p><p>　　And Alpha is the modification factor,Alpha the value size has reflected directly to the deviation and the debiation rate of change

31、 weighting degree.Through the adjustment modification factor Alpha,may change the control rule.When Alpha is big,indicated that is big to deviation's weighting,the step response is quick,the control energy mainly use

32、s 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 pro</p><p>　　u =α X E + (1-α )EC</p><p>　　An

33、d,modification factor α1,α2 in (0,1).</p><p>　　2.4 Logical threshold value control</p><p>　　This method establishes some control limit advance to certain controlled variable(threshold)the value

34、,when applies the brake,according to the computation real-time parameter value and the corresponding threshold value's size relations,determines wheel's state of motion,thus the control adjustment brake pressure

35、,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 Omeg</p><p>　　2.5 Double

36、 parameter control</p><p>　　Double parameter control's ABS,by the vehicle speed sensor(velocity radar),a round fast sensor,the control device(computer)and the implementing agency is composed.</p>

37、<p>　　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%

38、 one 20% ?????dose with the ideal slipping tate compares,fluctuates brake's braking force again through the solenoid valve.This kind tows the fast sensor commonly used Doppler velocity radar.When the automobile goes

39、the Doppler radar antenna by certain frequency to the earth launching elect</p><p>　　2.6 Single parameter control</p><p>　　It take controls wheel's angle tetarded velocity as the object,cont

40、rols wheel's 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 be

41、tween 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 i<

42、;/p><p>　　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 in

43、tensity is big,makes charging valve openning,the brake pressure to increase.</p><p>　　2)pressure maintenance,when wheel's brake divides in cylinder's pressure grows to certain value,charging valve cu

44、t-off closure.The support maintains at the compound state,three panels seal,maintain the brake pressures mutually.</p><p>　　3)voltage dropping,when the solenoid valve works,the support overcomes two spring&#

45、39;s 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 cond

46、ition.</p><p>　　The control device ECU primary mission is the signal which passes on various wheel's sensor carries on the computation,the analysis,the enlargement and the distintion,outputs again from t

47、hc 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 pro

48、tective device D.Electronic controller by 4101tz frequency actuation solenoid valves,this is </p><p>　　Mostly has provided this kind of single parameter control mode ABS in the American Chrysler custom car.T

49、t is loaded with a round fast sensor on passenger vehicle's four wheels.The installment has 45 teeth or 100 tooth's tooth rings on the axle tree,turns a fast sensor's sending attite to go against in the tooth

50、 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 wheel's speed-up or the decel</p><p>　　3.The

51、 problems by used the ABS system</p><p>　　(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 system

52、's normal work.</p><p>　　(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 th

53、e boiling point will have the corrosion, will also create the brake potency decline.</p><p>　　3)inspects the ABS anti-lock braking system to cramp out the power source frrst.</p><p>　　4.Trend

54、 of development</p><p>　　Uses 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 cont

55、roller's design because moreover on1y need determine wheel's angular speed is advantageous realizes therefore the load cost is low. This algor hm already drew close maturely for current automobile ABS sys

56、tem universal usebut it by no means best control algorithm. Because under the different state of roads eac</p><p>　　Easy to realize the stepless control based on the glide rate control algorithmand has the v

57、ery 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

58、 the following several aspects.</p><p>　　(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

59、 each performance</p><p>　　index 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 ch

60、aracteristic 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

61、 modelbut the predictive control has the basic characteristic which the forecast model the undle o</p><p>　　uncertainty disturbance and so on influence enables system's robustness to obtain the enhance

62、ment.</p><p>　　)1s smaller along with the volume the price is cheaper the reliable higher vehicle speed</p><p>　　sensor's appearance in the ABS system will increase the vehicle speed senso

63、r to become possible the defmite wheel slip rate will become is accurate and is fast. And the non-contact type's vehicle speed sensor (for example electro-optical type Doppler and so on) the present will</p>&

64、lt;p>　　most 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 mod

65、el is advantageous uses person's experience knowledge robustness is good simple practical and so on characteristics but widely will be used.</p><p>　　)Changes the multi-objectives by the sole ABS cont

66、rol objective integrated control [10]appeared 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 process

67、es and so on state acceleration curve) prevents the driving gear to have the slipping causes automobile's in actuation process yawing stability to change the operation ability and the pick-up and so on also has the e

68、nhancement.1n </p><p>　　unified 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 dispers

69、ion control calm question [1]enables the complete bikes overall performance to obtain the guarantee.</p><p><b>　　5 Summary</b></p><p>　　The automobi1e anti-lock braking system S)

70、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 thresh

71、old 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

72、control technolog</p><p>　　the integrated control by the network way and toward the multi-objective integrated controls enhances the system performance cost ratio the direction to develop.</p><p&g

73、t;　　汽車防抱死制動系統(tǒng)（ABS）</p><p><b>　　摘 要</b></p><p>　　本文簡要介紹了汽車防抱死制動系統(tǒng)（Anti-lock Braking System，簡稱ABS）的控制原理，對目前汽車防抱死制動系統(tǒng)采用的控制技術進行了綜述，并對其發(fā)展趨勢進行了預測。</p><p>　　關鍵詞：汽車；防抱死制動系統(tǒng)；控制技

74、術</p><p><b>　　概述</b></p><p>　　隨著汽車工業(yè)的迅猛發(fā)展和高速公路的不斷修建，汽車的行駛安全性越來越為人們重視。為了全面滿足制動過程中汽車對制動的要求，使制動器制動力分配更趨合理。清楚防抱死制動系統(tǒng)（簡稱ABS）已越來越多地應用在汽車上。</p><p>　　“ABS”中文譯為“防鎖死剎車系統(tǒng)”。他是一種具有防滑

75、、防鎖死等優(yōu)點的汽車安全控制系統(tǒng)。ABS是常規(guī)剎車裝置基礎上的改進型技術，可分為機械式和電子式兩種。</p><p>　　現(xiàn)在汽車上大量安裝防抱死制動系統(tǒng)，ABS既有普通制動系統(tǒng)的制動功能，又能防止車輪鎖死，使汽車在制動狀態(tài)下仍能轉向，保證汽車的制動方向穩(wěn)定性，防止產(chǎn)生側滑和跑偏，是目前汽車上最先進、制動效果最佳的制動裝置。</p><p>　　普通制動系統(tǒng)在濕滑路面上制動，或在緊急制動的

76、時候，車輪容易因制動力超過輪胎與地面的摩擦力而完全抱死。</p><p>　　清楚防抱死制動系統(tǒng)是指汽車在制動過程中能實時判定車輪的滑移率，自動調節(jié)作用在車輪上的制動力矩，防止車輪抱死。從而獲得最佳制動效能的電子裝置。它能把車輪的滑移率控制在一定的范圍之內，充分地利用輪胎與路面之間的附著力，有效地縮短制動距離，顯著地提高車輛制動時的可操縱性和穩(wěn)定性，從而避免了車輪抱死時易出現(xiàn)的各種交通事故。</p>

77、<p>　　隨著制動強度增加，車輪滾動成分越來越少，而滑移成分越來越多，一般用滑移S來說明制動過程中滑移成分的多少?；坡试酱螅瞥煞衷缴?。</p><p><b>　　其中：</b></p><p>　　u——車輪中心的速度；</p><p>　　r——沒有地面制動力時的車輪滾動半徑；</p><p>　

78、　w——車輪的角速度。</p><p>　　縱向和側向附著系數(shù)課表達為車輪滑移率的函數(shù)（如圖1）。最大的縱向附著系數(shù)所對應的滑移率稱為臨街穩(wěn)定點SK。根據(jù)控制理論吧滑移率小語SK 的區(qū)域稱為穩(wěn)定最大區(qū)，SK以后的為非穩(wěn)定穩(wěn)定去。ABS正是利用道路與輪胎之間的關系，強制性地把車輪滑移率控制在臨街穩(wěn)定點SK附近，使路面附著性能得到最充分的發(fā)揮，從而達到最佳的制動效果。</p><p>　　目前

79、所采用的ABS主要有輪速傳感器，電子控制單元，壓力控制閥和線束、管路等附件組成。ABS的開發(fā)主要是研究設計優(yōu)化運算和控制程序軟件，實現(xiàn)實時精確的控制調節(jié)的技術，同時提高硬件的水平。</p><p>　　目前ABS所采用的控制技術</p><p>　　ABS的控制效果很大程度上取決于系統(tǒng)所采用的控制技術[4]。目前所采用的主要是邏輯門限控制技術。為進一步提高ABS的性能，還提出了一些基于滑移

80、率的控制技術，如PID控制，滑移模態(tài)變結構控制，模糊控制等。每種控制均以不同的控制規(guī)律逼近期望的點。</p><p><b>　　2.1PID控制</b></p><p>　　定義期望滑移率S0與實際滑移率S之差為控制誤差e=S-S0,則PID的控制規(guī)律可表示為：</p><p>　　因此，ABS控制器的設計最后就歸結為，根據(jù)ABS動態(tài)系統(tǒng)，確

81、定出一組最佳的參數(shù)Kp、Ki和Kd，使車輪的滑移率以最快的方式逼近設定目標S0。</p><p>　　2.2滑移模態(tài)變結構控制</p><p>　　由汽車發(fā)表深圳的的基本原理可知，其中的過程的本質問題是把車輪的滑移率控制在附著系數(shù)的峰值點Sk，則滑動模態(tài)變結構根據(jù)系統(tǒng)當時的狀態(tài)、偏差及其導數(shù)值，在不同的控制區(qū)域，以理想帶開關的方式切換控制量的大小和符號，以保證系統(tǒng)在滑動區(qū)域很小的范圍內，狀

82、態(tài)軌跡（S,*S）焉滑動換節(jié)曲線滑向控制目標（Sk，0）。</p><p>　　通常去制動力矩為控制變量U，切換條件為：</p><p>　　其中Mb—、Mb+分別代表由調節(jié)系統(tǒng)所決定的制動力矩減少、增加兩種不同的狀態(tài)。</p><p>　　為切換函數(shù)，e=S-Sk 為實際滑移率相對目標的偏差。</p><p><b>　　2.3模

83、糊控制</b></p><p>　　對于以滑動率為控制對象的防抱死制動系統(tǒng)，其輸入量取得期望滑動率與車輪實際滑動率的偏差E以及偏差的變化率EC，輸出量為制動管路油壓。采用帶修正因子的模糊控制器，把用模糊推理算法形成的控制表概括為一個解析式：</p><p>　　其中α為修正因子，α值的大小直接反映了對偏差及偏差變化率的加權程度。通過調整修正因子α，就可以改變控制規(guī)則。當α較大時

84、，表明對偏差的加權大，階躍響應快，控制能量主要用于減少偏差，但易出現(xiàn)超調，但響應過程較慢。通常采用帶兩個α值的修正因子表達就可滿足性能要求，即：</p><p>　　u =α X E + (1-α )EC</p><p>　　其中，修正因子α1、α2屬于（0,1）且α1小于α2，控制系統(tǒng)在判斷E值得大小之后，選擇控制規(guī)則表達式。</p><p>　　2.4邏輯門限值

85、控制</p><p>　　此方法預先對若干個控制參數(shù)設定一些控制極限（門限）值，制動時，根據(jù)計算的實時參數(shù)值與對應門限值的大小關系，來判定車輪的運動狀態(tài)，從而控制調節(jié)制動壓力，以獲取足夠大的制動強度和良好的方向穩(wěn)定性。常作為ABS控制參數(shù)的有：車輪滑移率S，車輪轉動的角加（減）速度ω及其變化率。ω等三種秒速車輪運動情況或動力學狀態(tài)的參數(shù)。由于僅用一個控制參數(shù)難于保證ABS在各種形式條件下都具有良好的性能，因此，目

86、前邏輯門限值控制方法通常將車輪轉動的角加（減）速度作為主要控制參數(shù)，而將車輪的華滑動率S作為輔助控制參數(shù)。其中滑動率是從各輪速信號按一定邏輯確定汽車的參考速度后，計算出的參考滑動率，與實際滑動率存在著差異。</p><p><b>　　2.5雙參數(shù)控制</b></p><p>　　雙參數(shù)控制的ABS ，由車速傳感器(測速雷達、輪速傳感器、控制裝置(電腦)和執(zhí)行機構組成

87、。</p><p>　　其工作原理是車速傳感器和輪速傳感器，分別將車速和輪速信號輸入電腦，由電腦計算出實際滑移率，并與理想滑移率15 %—20 %作比較，再通過電磁閥增減制動器的制動力。</p><p>　　這種曳速傳感器常用多普勒測速雷達。當汽車行駛時，多普勒雷達天線以一定頻率不斷向地面發(fā)射電磁波，同時又接收反射回來的電磁波，測量汽車雷達發(fā)射與接收的差值， 便可以準確計算出汽車車速。而輪

88、速傳感器裝在變速器外殼，由變速器輸出軸驅動， 它是一個脈沖電機，所產(chǎn)生的頻率與輪速成正比。執(zhí)行機構由電磁閥及繼電器等組成。電磁閥調整制動力，以便保持理想的滑移率。這種ABS 可保證滑移率的理想控制，防抱制動性能好，但由于增加了一個測速雷達， 因此結構較復雜，成本也較高。</p><p>　　2. 6 單參數(shù)控制</p><p>　　它以控制車輪的角減速度為對象，控制車輪的制動力，實現(xiàn)防抱死

89、制動，其結構主要由輪速傳感器、控制器(電腦)及電磁閥組成。為了準確無誤地測量輪速，傳感頭與車輪齒圈間應留有1mm 間隙。為避免水、泥、灰塵對傳感器的影響，安裝前應將傳感器加注黃油。電磁閥用于車輪制動器的壓力調節(jié)。對于四通道制動系統(tǒng)，一個車輪圈有一個電磁閥;三通道制動系統(tǒng)， 每個前輪擁有一個，兩個后輪共用一個。電磁閥有三個液壓孔，分別與制動主缸與車輪制動分缸相連，并能實現(xiàn)壓力升高、壓力保持、壓力降低的調壓功能。工作原理如下:</p&

90、gt;<p>　　1) 升壓在電磁閥不工作時，制動主缸接口和各制動分缸接口直通。由于主彈簧強度大，使進油閥開啟，制動器壓力增加。</p><p>　　2) 壓力保持當車輪的制動分缸中的壓力增長到一定值時，進油閥切斷關閉。支架就保持</p><p>　　在中間狀態(tài)，三個孔間相互密封，保持制動壓力。</p><p>　　3) 降壓當電磁閥工作時，支架克服兩

91、個彈簧的彈力，打開卸荷肉使制動分缸壓力降低。壓力一旦降低，電磁閥就轉換到壓力保持狀態(tài)，或升壓的準備狀態(tài)。</p><p>　　控制裝置ECU 的主要任務是把各車輪的傳感器傳回來的信號進行計算、分析、放大和判別，再由輸出級將指令信號輸出到電磁閥，去執(zhí)行制動壓力調節(jié)任務。電子控制裝置?</p><p>　　由四大部分組成，輸入級A 、控制器B 、輸出級C ， 穩(wěn)壓與保護裝置D 0 電子控制器以

92、4 101tz 的頻率驅動電磁閥，這是駕駛員無法做到的。這種單參數(shù)控制方式的A邸，由于結構簡單、成本低， 故目前使用較廣。</p><p>　　在美國克萊斯勒型高級轎車中大多配備了這種單參數(shù)控制方式的ABS 0 它在轎車的四個輪上都裝有輪速傳感器。在車輪軸上安裝有45 齒或100 齒的齒圈，輪速傳感器的傳感頭裝在齒圈的頂上。當車輪轉動時，使傳感器不斷產(chǎn)生電壓信號，并輸入電腦，與RoM中理想速度比較，算出車輪的增速

93、或減速，向電磁閥發(fā)出升壓或卸壓的指令，以控制制動分缸制動力。</p><p>　　ABS使用中注意的問題</p><p>　　1) 更換制動器或更換液壓制動系部件后，應排凈制動管路中的空氣，以免影響制動系統(tǒng)的正常工作。</p><p>　　2) 裝有ABS 的汽車，每年應更換一次制動液。否則，制動液吸濕性很強，含水后不僅會降低沸點，產(chǎn)生腐蝕，而且還會造成制動效能衰退

94、。</p><p>　　3) 檢查ABS 防抱死制動系統(tǒng)前應先拔去電源。</p><p><b>　　發(fā)展趨勢</b></p><p>　　采用邏輯門限值控制算法，可避免一系列繁雜的理論分析和對一些不確定因素的定量計量。簡化了控制器的設計，而且因僅需測定車輪的角速度，便于實現(xiàn)，所以裝車成本低。該算法現(xiàn)己趨近成熟，為當前汽車ABS 系統(tǒng)所普遍采用

95、，但它并非最佳的控制算法。由于不同路況下各種門限值及保壓時間都是經(jīng)過反復試驗得出的經(jīng)驗數(shù)值，沒有十分明確的理論依據(jù)，故ABS 開發(fā)的周期長，且控制品質難以保證。</p><p>　　基于滑動率的控制算法容易實現(xiàn)連續(xù)控制，且有十分明確的理論加以指導，但目前制約其發(fā)展的瓶頸主要是實現(xiàn)的成本問題，根據(jù)我們的研究認為，今后ABS 控制算法的發(fā)展方向將在以下幾方面。</p><p>　　(1) 針對

96、當前廣泛采用的邏輯門限值控制算法所存在的缺點，研究能跟蹤路面特性變化，使ABS 各項性能指標始終處于最佳狀態(tài)的控制算法。其中預測控制技術值得重視。由于在制動過程中，輪胎與路面間的摩擦特性導致防抱死制動系統(tǒng)具有非常明顯的非線性、時變性和不確定性。因而難于建立其精確的數(shù)學模型，而預測控制具有預測模型、滾動優(yōu)化和反饋校正的基本特性，可根據(jù)某一優(yōu)化指標設計控制系統(tǒng)，確定一個控制量的時間序列，使未來一段時間內被調量與經(jīng)過柔化后的期望軌跡之間的誤差

97、為最小。由于該算法采用的是不斷在線滾動優(yōu)化，且在優(yōu)化過程中不斷通過實測系統(tǒng)輸出與預測模型輸出的誤差來進行反饋校正，所以能在一定程度上克服由于預測模型誤差和某些不確定性干擾等的影響，使系統(tǒng)的魯棒性得到增強。</p><p>　　(2) 隨著體積更小，價格更便宜，可靠性更高的車速傳感器的出現(xiàn)， ABS 系統(tǒng)中增加車速傳感器成為可能，確定車輪滑動率將變得準確而快速。其中非接觸式的車速傳感器(如光電式、多譜勒儀等)今后最

98、有可能應用于汽車ABS 系統(tǒng)中。此時基于滑動率的控制算法就可被重視。其中模糊控制將以其不依賴對象的數(shù)學模型，便于利用人的經(jīng)驗知識， 魯棒'性好，簡單實用等特點而會被廣泛采用。</p><p>　　(3) 由單一的ABS 控制目標轉向多目標的綜合控制[10J ，其中己出現(xiàn)的牽引力控制系統(tǒng)CTCS) 不僅能夠在制動過程中防止車輪發(fā)生抱死，而且能夠在驅動過程中(特別是在起步、加速、轉彎等過程中)防止驅動輪發(fā)生滑

99、轉，使汽車在驅動過程中的方向穩(wěn)定性、轉向操縱能力和加速性能等也都得到提高。未來汽車電子控制系統(tǒng)將朝著從多電子控制單元CECU) 的分散的獨立控制向單- ECU 的整車控制，以網(wǎng)絡的方式實現(xiàn)數(shù)據(jù)共享和綜合控制的方向發(fā)展;或者向動態(tài)遞階控制方向發(fā)展，即各分散控制系統(tǒng)的ECU 不僅是各自獨立地構造自己的動態(tài)補償器，而且要再統(tǒng)一地建立一個高層的動態(tài)協(xié)調器來幫助確定各ECU 的控制策略，以增強各ECU 的控制能力，解決分散控制系統(tǒng)存在不穩(wěn)定模時不

100、能用動態(tài)分散控制的問題[ll] ，使整車綜合性能得到保證。</p><p><b>　　總結</b></p><p>　　汽車防抱死制動系統(tǒng)CABS) 能提高汽車在低附著系數(shù)或變附著系數(shù)路面條件下的制動性能。目前ABS 的控制技術主要采用邏輯門限值控制方法， 但隨著車速傳感器技術的發(fā)展，基于車輪滑動率的各種控制算法將被廣泛的重視和采用。另外。未來汽車電子控制技術與裝置

101、將以網(wǎng)絡的方式實現(xiàn)資源共享和綜合控制，并朝著多目標綜合控制，以提高系統(tǒng)性能成本比的方向發(fā)展。</p><p><b>　　參考文獻</b></p><p>　　l 余志生. 汽車理論(修訂版) .北京:機械工業(yè)出版社， 1993</p><p>　　2 李朝祿.汽車制動防抱裝置CABS) 構造與原理. 劉榮華譯.北京:機械工業(yè)出版社，</

102、p><p><b>　　1995</b></p><p>　　3 柯愈治， 謝懷喧等.汽車防抱制動系統(tǒng)結構原理與檢修.北京:人民交通出版社， 1998</p><p>　　4 潘旭峰.現(xiàn)代汽車電子技術.北京:北京理工大學出版社， 1998</p><p>　　5 周云山， 于秀敏. 汽車電控系統(tǒng)理論與設計.北京:北京理工大學