轿车悬架设计—麦弗逊独立悬架文献综述

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1、广西科技大学（筹）毕业设计（论文）附录资料课题名称 轿车悬架设计麦弗逊独立悬架 学 院 汽车与交通学院 专 业 交通运输（汽车电子技术与检测诊断） 班 级 交Y091 学 号 200900207042 姓 名 周文江 指导教师 陈坤 2013年 1月 6 日目 录一、英文原文.3二、中文翻译.9三、方案论证.14一、英文翻译Survey of Controllable Suspension System for Off-road Vehicles Abstract：The controllable suspension system can improve the performances o

2、f off-road vehicles both on road and cross- countrySo far，four controllable suspensions，that is，body height control，active，semi-active and slow-active suspensions，have been developedFor off-road vehicles，the slow-active suspension and the semi-active suspension which have controllable stiffness，damp

3、ing and body height are more appropriate to useFor many years，some control methodologies for controllable suspension systems have been developed along with the development of modern control theory，and two or more original control method s are integrated as a new control method Today，for military or

4、civilian off-road vehicles，the R& D of controllable suspension systems is ongoing Key Words：control theory；survey；controllable suspension；off-road vehicle The suspension system is an important part of the vehicle， which influences riding comfort and handle-stability greatlySince the first pair of le

5、af spring was used in carriage，suspension systems were uncontrollable for a long time and named as passive suspension systemA typical passive suspension system consists of springs，dampers and some control arms， which are once invariable designedBut，the roads for vehicle running are variousFor the ve

6、hicles suspension system，different kinds of roads make different inputsThus ，different suspension parameters， such as stiffness，damping and body height，should be designed to minimize the impact from ground and the jounce of bodyHowever，its impossible that the traditional vehicles with invariable pas

7、sive suspension system perform well on multifarious roadsFor off-road vehicles，the conflict between changeful roads and changeless suspensions is more projecting than road vehiclesMost of off-road vehicles are still using the passive suspension systems and have higher stiffness，damping and body heig

8、ht to overcome the rough road or cross-countryHowever，these vehicles show worse riding comfort and handle stability than road vehicles on normal roadsFor these reasons，the controllable suspension systems should be the best choice for vehicles，especially for the off-road vehicles 1 Categories of Cont

9、rollable Suspension SystemThe controllable suspension system is a general reference of the non-passive suspension system，the antonym of passive suspension should be active suspension But，in the suspension control，the active suspension is a special type of controllable suspensionsToday，the controllab

10、le suspensions can be divided into four categories according to the controlled objects and structuresThey are body height control， active，semi-active and slow-active suspensions The quarter-vehicle vibration models of these different controllable suspension systems are shown in Fig1 11 Body Height C

11、ontrol Suspension System The body height control suspension system is the pioneer of controllable suspension systemsThe first body height control suspension system was used in CitrOen DS19 launched in 1955 and made in FranceIt adopts four controllable air springs and can adjust obviously that the ac

12、tive suspension system improves the body height according to run condition and load to guarantee proper wheel travels1 . This kind of system is the simplest controllable suspension system，usually found in luxurious buses and pickup trucksA bus equipped with this system can keep the body height uncha

13、nging whether it is empty or fullThe body height control suspensions are also designed for the pickup trucks real suspensions，it can keep the body horizontal，whether it links a trailer or not The main structural difference between the body height control suspension and the passive suspension is that

14、 the former has a height control system additionally，which includes body height sensors，height drives and a controller，as shown in Fig1(a) It aims at controlling the body height only， though the suspensions stiffness and damping also change in the control processThe inputs mainly include the speed o

15、f vehicle and the distance between body and wheel，which are collected by speed and displacement sensorsThe proper body height data shall be calculated based on a certain control strategy by the body height control system and output to the executing mechanism 12 Active Suspension System The concept o

16、f active suspension was presented early in 19542Thompson，in 1960s，consummated its basic structure and control law and proved that so-called ful1-active suspension system could improve the performances of vehicle effectivelySince 1980s， the research achievements on active suspension had been put into

17、 use. Some testing vehicles were built3 . The experiment for these vehicles showed obviously that the active suspension system improves vehicles performance greatly. The active suspension system consists of sensors,controllers and force actuators，as shown in Fig1（b）4. And，for driving force actuators

18、，an additional power is necessary It adopts the force actuator to replace the customary spring and absorberThe force actuators can be controlled to produce appropriate forces to support the body，whenever the vehicle runs in any road The body and wheel sensors are used to measure the accelerations of

19、 the body and wheel and provide these data to the controllerThe latter processes these data and outputs some instructions to the force actuator according to predefined control strategy which determines the quality of the active suspension system Although the active suspension system has been present

20、ed for more than fifty years，it hasnt been largely commercialized yet up to nowOf course，the technical and economic reasons coexist In technology，todays active suspension systems can work well in low frequency band but not in high frequency，since the force actuators seems too stiff to control5 Altho

21、ugh some active suspension systems can operate well up to 70 Hz6，they will consume energy very much7 One of the methods to reduce the power consumption uses springs and dampers in parallel with the actuatorsIn addition，it also improves the security of the active suspension systemBut,as a negative re

22、sult,the system response will be decreased In economy，building and operating an active suspension system costs too muchIt fatally limits the active suspension systems to be extended 13 Semi-active Suspension System The semi-active suspension system was presented later but applied earlier to the vehi

23、cles than active suspension systemThe controllable suspension system with adjustable stiffness and damping was introduced in early 1970sIt almost does not consume energy，since the force actuators which need too much energy are eliminatedSo，it is called as semiactive or no power active suspension sys

24、tem The common semiactive suspension systems only control the damping of suspension actively，and some senior semiactive suspension systems also control the stiffnessIn fact，a semi-active suspension system is just a passive suspension system with controllable damping and stiffness，as shown in Fig1 (c

25、)So ，its performances are still not as good as the active suspension system A famous control model of the semiactive suspension system was so-called Sky-Hook Damping Control proposed by Karnopp in 19738In this model，a supposed inertial damper，called as Sky-Hook damper，is set between a sprung mass an

26、d a virtual fixed Sky-HookThe force of the Sky-Hook damper proportional to the relative speed of the sprung mass to the Sky-Hook can reduce the jounce of the vehicles For the Sky-Hook and Sky-Hook damper are both inexistence in real vehicles，an controlled adjustable damper is set to replace the pass

27、ive damper between the sprung mass and unsprung mass in real Sky-Hook modelTheoretically，the damping force should change continuously and in real-time9，but it is usually hard to be done in real vehiclesA control model for the semi-active suspension systems with discrete adjustable damping and stiffn

28、ess was proposed by Margolis in 197510 Several dampers or springs are paralleled，thus，if one or more of them are shut off，the damping or stiffness of the suspension system will change discretelyFor it is easy to achieve，the Margolis model have been used in so me carsSome semi-active suspension syste

29、ms are even added the body height control to improve the vehicle performancesThis controllable height semi-active suspension system has been used in some luxurious car and SUV recentlySome of them are named as the active suspension by their manufacturer，but they are still different from the real act

30、ive suspension14 Slow-active Suspension System The slow-active suspension system is presented later but more remarkablyIts essential structure can be regarded as a series of an active suspension system and a passive suspension system，as shown in Fig1 (d)As the passive suspension system can isolates

31、high-frequency vibration well，the active suspension system can only isolate low-frequency vibrationThe force actuators only work in the low-frequency band， power consumption are reduce evidentlyTheoretically，the slow-active suspension system still responds more slowly than the real active suspension

32、 system， this is the reason why it is so named11 Some other names，such as narrow bandwidth active suspension system or limited bandwidth suspension system，are also foundBy contrast，the real active suspension system is usually called as full-active suspension system or broad bandwidth active suspensi

33、on system12 To improve performances of the slow-active suspension system，the springs and dampers in the system should be controllableThis slow-active suspension system can be regarded as a series of an active suspension and a semi-active suspension As an unavoidable result，the control system and mec

34、hanical structure are more complex The performances of the slow-active suspension system are almost as goo d as the full-active suspension system，and the power consumption is fairly lessIts prospect will be very wel12 Control Methodologies for Controllable Suspension Systems The control theories for

35、 controllable suspension systems grow along with the development of modem control theoryRecently，the typical control strategies include LQG (linear-quadratic-Gaussian)optimal control，model reference adaptiveself-tuning control， preview control，fuzzy control，neural network control，etc 2.1 LQG Optimal

36、 Control Strategy LQG For the linear vibration model of the active suspension systems，the control attempts to minimize the integrated weight of body vertical acceleration，wheel dynamic load and wheel dynamic travelThe objective function of the control system is quadraticAnd the disturbance input fro

37、m road is a stochastic process that can be deal with as a Gaussian white noise Thus，the suspension control problem can be regarded as a typical LQG optimal control13 According to LQG optimal control strategy，the optimal control force Uo can be defined a U。=KX (1) In the formula，K is a control feedba

38、ck gain matrixX is a state variable matrix expressed as where Z2一Z1 is the wheel dynamic travel，Z2 is the sprung mass speed，Z1一q is the wheel dynamic compression， Z1 is the unsprung mass speed 。 22 Fuzzy Control Strategy Differing from the traditional mathematic and control theory，the fuzzy control

39、strategy is based on fuzzy set theory created by an American cybernetics expert，Zadeh，in 1965It uses language analytical rule like IF-THENThis comprehensible rule can be easily transformed into an acceptable control algorithm by computer The fuzzy control has been demonstrated to be able to control

40、the complex or nonlinear systems efficiently Because the vehicle suspension system is complex，time-varying and nonlinear system， the fuzzy control is applied to this kind of system obviously more proper than the traditional control18 However，it should be noticed that the advantage of fuzzy control w

41、ill be lost if the fuzzy control rules are imperfect19 And in general,the fuzzy control rules are obtained very difficultly without a lot of calculations and experimentsThe fuzzy control implementation can be divided into three stepsFirstly，crisp inputs are fuzzified as ambiguities，secondly，ambiguou

42、s decision is made using fuzzy inference engine，and thirdly，the ambiguities are resolved to crisp outputs， as shown in Fig5 In Fig5，S is a value predefined by the system， y is the data measured by sensors，和 are the crisp values of system error and its change rate，E and EC are the fuzzy set of 和，U is

43、 the fuzzy output of fuzzy inference and u is the crisp output after defuzzifying U Fuzzy logic has been seldom used in the off-road vehiclesAlthough related papers on fuzzy control of suspension systems have increased in recent years，most of them stay in theoretical research and simulationThe reaso

44、n is that the acquirement of the fuzzy rules is very difficult and needs a lot of calculation and experimental verification 23 Neural Network Control Strategy NN( neural network)control has become a new control methodologies，after the research of ANN (artificial neural network) made great Progress i

45、n 1980sNN is a nonlinear and parallel calculator made of a lot of neural element and their jointsThe weights of the different joints are different in NN system.Adjusting the joint weights in NN system is a process called as“study” NN has two main study algorithmsone of them is directed study algorit

46、hm and another is undirected study algorithmFor example，back-propagation algorithm shown in Fig6 is a typical direct study algorithm in NN control20 The application of NN to vehicle suspension control has a favourable prospect，since NN has powerful study ability and is good at solving the nonlinear

47、and uncertain system problems Research shows that the active suspension systems using NN control strategy has better performance than the active suspension systems using traditional LQG optimal control strategy2l But，NN likes a black box，its study process is impossible to be observed，and its outputs

48、 are hard to be explainedAs a result，the reliability and accept-ability of NN control are weakened NN control strategy applied to the real off-road vehicle suspension systems has not been reported yet However：along with the development of the NN control methodologies and relative hardware products，t

49、he NN controlled suspension systems for the off-road vehicles will be designed 24 Other Suspension Control Strategies Some other control strategies can also be used for vehicle suspension， such as traditional PID control22 ， variable structure sliding-mode control23 ， random sub-optimal control24 ，

50、Hand (norm and structure singular value)control 25-26，etc Recently，the control methodologies for vehicle suspension systems trend to combine two original control methods and create a new control method，such as adaptive fuzzy control，NN fuzzy control，fuzzy PID control，NN PID control，sliding-mode PID

51、control，genetic fuzzy control，genetic NN control，and so on.二、中文翻译越野车可控悬架系统综述摘要：可控悬架可以使越野车辆兼顾越野行驶和道路行驶.可控悬架可分为车高控制、主动、半主动和慢主动悬架.对于越野车辆而言,慢主动悬架最适合实际应用.可控悬架控制方法随着现代控制理论的发展而发展,并出现了一些由多种原有控制理论相互结合而成的新控制方法.目前,在军用和民用越野车辆上,可控悬架的研究与开发仍处于试验阶段。关键词：控制理论 ； 可控悬架 ； 越野车辆 ；主动悬架 悬挂系统是汽车的重要组成部分， 其对平顺性（乘坐舒适性）和安全性（操纵稳定性

52、） 影响很大。 由于第一对钢板弹簧是用于车箱 ， 悬架系统很长一段时间内是不可控制的而命名为被动悬架系统。传统的被动悬架主要由弹性元件、阻尼元件和控制元件组成 ， 这种设计一直不变。 但是，车辆运行的道路有所不同。 相对不同类型的道路车辆悬架的设计有所不同。从而，不同的悬挂参数，如刚度，阻尼和车身高度，设计时应尽量减少来自地面的影响和身体的震动。然而，装配着被动悬架系统的传统车辆不可能在不同的道路上都良好工作。对于越野车，多变的道路与固定悬架之间的冲突比道路车辆更为突出。越野车大部分仍采用被动式悬挂系统，具有较高刚度、阻尼和车身，能克服崎岖道路。然而，这些车辆的乘坐舒适性和操作稳定性比道路车辆

53、的差。基于这些原因，可控悬架系统应是车辆的最佳选择，特别是对于越野车。1 可控悬架系统的分类 可控悬架系统可做为非被动悬架系统的一个参考，主动悬架与被动悬架相反。 但是，在悬架控制上，主动悬架是一种特殊类型可控悬架。现今，可控悬架根据控制对象和结构可分为四类：身体的高度控制，主动悬架，半主动和慢主动悬架。 四种不同可控悬架系统的车辆振动模型如图1所示。11 车身高度控制悬挂系统 车身高度控制悬挂系统是可控悬架系统的先驱。第一个车身高度控制悬挂系统是雪铁龙于1955年在法国制造并在DS19上使用。它采用了四个可控制和调整的空气弹簧，主动悬架系统明显的提高了行驶条件，且根据负载来保证车轮机构保持适

54、当的高度。这种系统是最简单的控制悬挂系统，通常用在豪华车和皮卡。公共汽车装这种系统可以保持身体高度不变，无论空车还是满载。车身高度控制悬挂也是为皮卡的真正悬架而设计，它可以保持身体的水平，无论连结拖架与否。主要机构之间的高度控制悬架和被动悬架结构上的差异是，前者具有高度控制系统外，其中包括身高传感器，驱动器和控制器的高度，如在图1（a）所示。其目的只是控制车高，尽管悬架的刚度和阻尼在控制过程也改变。这些数据主要包括车辆的速度和车身与车轮之间的距离，由速度和位移传感器收集。正确的身高数据的计算方法应根据一定的控制模式，身高控制系统和输出执行机构。12 主动悬架系统 早在1954年Thompson

55、便提出主动悬架概念，完善其基本结构和控制，并证明了全主动悬挂系统可以提高车辆有效性能。自1980年代以来，主动悬架的研究成果便投入使用。并制造了一些测试车辆。这些车辆的试验表明，主动悬架系统明显地提高汽车的性能。 主动悬架系统包括传感器，控制器和驱动执行器， 如图1（b）所示。另外，驱动执行器需要一个额外的动力。 它用驱动执行器取代传统弹簧和减震器。当车辆在任何道路上行驶时驱动执行器可产生一定的力来支撑车身。 车身和车轮传感器用来测量车身和车轮的加速度，并提供数据到控制器。传感器处理这些数据后输出一些指令给执行器，由已确定的控制策略决定主动悬架系统的质量。 虽然主动悬架系统已经出现了50多年，

56、但至今仍未实现量产。当然，技术和经济原因都有。 技术方面，如今的主动悬架系统可以在低频段很好的工作但高频不能，因为驱动执行器太稳固而难以控制。虽然一些主动悬架系统可以很好地运转到70赫兹，但消耗很多能源。一个降低功率消耗和阻尼的方法是采用平行弹簧和阻尼器。此外，还提高了主动悬架系统的安全。但，不足的是，该系统的响应将下降。在经济，装配主动悬架系统的成本过大，极大地限制了主动悬架系统的推广。13 半主动悬架系统 与之前的主动悬架车辆相比，半主动悬架系统的应用提出了更高要求。在70年代初可调刚度和可调阻尼引入了可控悬架系统。它几乎不消耗能源，因为此驱动执行器需要太多的能源已被淘汰。因此，它被称为是

57、半主动或无动力主动悬架系统。 常见的半主动悬架系统仅控制主悬架阻尼，而一些高级半主动悬挂系统同时控制刚度。实际上，一个半主动悬架系统仅是一个被动悬架系统与可控阻尼和刚度的结合，如图1（c）所示。所以，它的性能不如主动悬架系统的好。 Karnopp在1973年提出了著名的半主动悬架系统的控制模型，所谓的天棚阻尼控制模型。在此模型中，一个假定的惯性阻尼器，叫作天棚阻尼器。它设置在一个弹簧质量和一个虚拟的固定天棚之间。与天棚的弹簧质量的相对速度成正比的天棚阻尼器的力量可以减少车辆的颠簸。 由于天棚与天棚阻尼器都不存在真正的车辆中，因此，在真正的天棚模式1中，可以用一个可控制可调节阻尼器代替弹簧质量和

58、非弹簧阻尼器之间的被动阻尼器。从理论上来说，阻尼是连续不断变化的，但这同时很难在真正的车辆中实现。 1975年，马戈利斯提出了一种有离散可调阻尼和刚度的半主动悬架系统的控制模式。几个阻尼器或弹簧并联，这样，如果它们中有一个或者几个关闭了，悬架系统的阻尼和刚度将离散变化。由于这样很容易实现，马戈利斯模型已被应用于一些汽车。 一些半主动悬架系统更是增加了车身高度控制，以提高车辆性能。最近这个高度可控半主动悬挂系统已经被用于一些豪华车和SUV。其中一些被它们的制造商命名为主动悬架，但是它们仍然与真正的主动悬架有所不同。 14 慢主动悬架系统 慢主动悬架系统较晚提出，但更引人关注。它的基本结构可以看作

59、是一系列主动悬架系统和被动悬架系统，如图1（d）所示。被动悬架系统能很好地隔离高频震动，而主动悬架系统只能隔离低频震动。 驱动执行器只能在低频传动带工作，功率消耗明显降低。理论上，慢主动悬架系统的反应速度仍然比真正的主动悬架系统慢得多，这就是它被这样命名的原因。但也发现它其他一些名称，如窄带主动式悬挂系统或有限带式悬架系统。与此相反的，真正的主动悬架系统通常称为全主动式悬挂系统或带宽式主动悬架系统。 为了提高慢主动悬架系统的性能，系统中的弹簧和阻尼器应该是可控制的。这种慢主动悬架系统可以当作一系列主动悬架和半主动悬架。 作为一个不可避免的结果，控制系统和机械结构更为复杂。 慢主动悬架系统的性能

60、几乎和全主动悬架系统的性能一样好，而且电力耗费也相当少。它的前景将非常好。2 可控悬架系统的控制方法 可控悬架系统的控制理论与现代控制理论的同时发展。最近，典型控制策略包括LQG（线性二次高斯）最优控制，模型参考自适应/自校正控制，预见控制，模糊控制，神经网络控制等 2.1 LQG最优控制策略 为了主动悬架系统线性振动模型，控制器试图最小化身体垂直加速度，车轮动载荷和车轮跑偏。 该控制系统的目标函数为二次函数。 来自道路的不确定干扰可以作为处理高斯白噪声。因此，悬架控制问题可以当作一个典型的LQG最优控制。 据LQG最优控制策略，最优控制力Uo可以被定义为 U。=KX (1) 在公式中，K是一

61、个控制反馈增益矩阵。X是一个状态变量，表示为 其中Z2一Z1是车轮偏移量，Z2是簧载质量的速度，Z1一q是车轮压缩量，Z1是簧下质量速度。 22 模糊控制策略 不同于传统的数学和控制理论， 模糊控制策略是美国控制论专家Zadeh于1965年根据模糊论创建的理论。 它使用假设的语言分析规则。 这种易理解的规则可以转化成计算机可以接受的控制算法。 模糊控制已被证明能够有效控制复杂的或非线性的系统。 因为车辆悬挂系统是复杂的，变化的和非线性的系统， 模糊控制应用到这种系统显然比传统的控制更适当的。 但是，除模糊控制的优点外，还应看到其规则的不足。 而在一般情况下，没有大量的计算和实验模糊控制规则难以

62、理解。模糊控制的实现可以分为三个步骤。 首先，精确的输入被模糊化， 第二，使用模糊的推断得出模糊的结果， 第三，将结果清晰输出，如图5所示。 在图5，S是由系统预定义的值， y是传感器测量的数据， 和是系统误差及其变化率的精确值， E和EC是模糊集和， U为模糊输出，u为清晰输出。 模糊逻辑已经很少使用在越野车上。 虽然与悬挂系统模糊控制相关论文在近年有所增加， 但大多数停留在理论研究和模拟上。 原因是，获取模糊规则是非常困难的，需要大量的计算和实验验证。 23 神经网络控制策略 NN（神经网络）控制已成为一个新的控制方法，在1980年接着ANN（人工神经网络）的研究后有了巨大进步 。 神经网络是一种由很多神经元和接头构成的非线性并行计算机。 在神经网络系统不同重量折接头有所不同。在NN系统中调整接头重量的过程叫“