选题申报表.doc

发动机怠速PID控制研究【论文】

收藏

压缩包内文档预览:
预览图
编号:10109475    类型:共享资源    大小:2.66MB    格式:ZIP    上传时间:2018-05-17 上传人:机****料 IP属地:河南
12
积分
关 键 词:
发动机 pid 控制 节制 研究 钻研 论文
资源描述:
发动机怠速PID控制研究【论文】,发动机,pid,控制,节制,研究,钻研,论文
内容简介:
Control Engineering Practice 14a, MartinUniversityaccepted3throttlecompensators. The emphasis is on the development of an adaptive control strategy, which is aimed to enhance the control strategyrobustness with respect to process parameter variations, caused by production deviations, variations of external conditions, andis being replaced in modern vehicles by an electronicthrottle, where the link between the gas pedal and theusually include an inner current controller. The throttlemotion is constrained by a dual return spring whichproviding a linear system-like behavior for a wide rangeof throttle operation. The step response of controlsystem is characterized by the settling time of approxi-ARTICLE IN PRESSC3Corresponding author. Tel.: +385 1 6168325; fax: +385 1 6168351.E-mail addresses: danijel.pavkovicfsb.hr (D. Pavkovic ),mately 70 ms and the steady-state accuracy better than0.11. The control strategy has been tuned based on the0967-0661/$ - see front matter r 2005 Elsevier Ltd. All rights reserved.doi:10.1016/j.conengprac.2005.01.006josko.deurfsb.hr (J. Deur), mjansz (M. Jansz),nedjeljko.pericfer.hr (N. Peric ).throttle plate is realized by means of a DC servomotor.In this way, the engine control unit can correct thethrottle position reference value for specic engineoperating modes, thus improving drivability, fueleconomy, and emissions, and also providing theimplementation of engine-based vehicle dynamics con-trol systems including traction control (Huber, Lieben-roth-Leden, Maisch, Automotive control; Electric throttle control; Friction; Nonlinear control; Auto-tuner; Self-tuning control1. IntroductionIn conventional vehicles the driver gas pedal ismechanically linked to the throttle plate. This systemchopper, and a position control strategy. A photographof an electronic throttle body is shown in Fig. 1a, and itsinternal structure is depicted in the lower right part ofFig. 1b. The electronic throttle servo system does notaging. The adaptive strategy consists of auto-tuning and self-tuning algorithms. The auto-tuner provides automatic tuning of theAdaptive control of automotiveDanijel Pavkovica,C3, Jos ko DeuraFaculty of Mechanical Engineering and Naval Architecture,bFord Motor Company Ltd., Product Development Europe, DuntoncFaculty of Electrical Engineering and Computing, UniversitReceived 16 June 2003;Available onlineAbstractAn electronic throttle is a DC servo drive which positions theThis paper presents an electronic throttle control strategy consisting(2006) 121136electronic throttleJanszb, Nedjeljko Periccof Zagreb, I. Lucica 5, HR-10000 Zagreb, CroatiaTechnical Centre, Laindon, Basildon, Essex SS15 6EE, UKy of Zagreb, Unska 3, HR-10000, Zagreb, Croatia19 January 2005March 2005plate, thus providing drive-by-wire control of engine torque.of a PID controller, and nonlinear friction and /locate/conengpracARTICLE IN PRESSnic throttle process model (see Pavkovic , Deur, Jansz, Hashimoto,Ishiguro, Yasui, Rossi, Tilli, Yokoyama,Shimizu, CMS;CKchKaKt. (2)following condition is satised:KdbKl2KsJp, (6)the linear process dynamics can be represented by asimple integral+lag model (IT1model) (see Deur et al.,2004):GpsysusKps1 Tems, (7)where the process gain Kpand the electromechanicaltime constant Temare given byKp KchKl=Kv,Tem J=Kd. 8According to identication results in Pavkovic et al.(2003), the condition (6) is satised in the region abovethe limp home position (y4yLH; cf. slopes of the processstatic curve in Fig. 2 for yoyLHand y4yLH).ARTICLE IN PRESSPractice 14 (2006) 121136Fig. 4. Block diagram of electronic throttle process. u; ua; uemf-commanded signal, armature voltage, and back electromotive force; ia- armature current; mm; ms; mf; mL- motor, return spring, friction, andload torque; ym;y - motor and throttle position; om- motor speed; Kch- chopper gain; Ka; Kt; Kv- armature, torque, and voltage gain; J -total moment of inertia; 1/Kl- gear ratio; yLH- limp-home position;MC; MS- Coulomb and breakaway friction.D. Pavkovic et al. / Control Engineering124In general, the values of LH voltages ULH7and theslopes of process static curve Du=DyC6above(+)andbelow(C0)the LH position yLHare not equal.According to Pavkovic et al. (2003), the armaturetime constant is very small (TaC25 0:5 ms), and it doesnot affect the linear process dynamics. Thus, the linearprocess model (Fig. 4 with mf 0andms KsKly) canbe described by the second-order lag model:GpsysusKp21 ap1s ap2s2, (3)withKp2KchKaKtKsKl; ap1KdKsK2l; ap2JKsK2l, (4)where Kdis the damping coefcient due to the backelectromotive force uemf:Kd KaKtKv. (5)If the return spring stiffness Ksis small enough (i.e. ifthe slope of the process static curve is small), so that the3. Nonlinear control strategyFig. 5. Process static curve.Fig. 6 shows the block diagram of the proposedelectronic throttle control strategy. The control strategyconsists of a PID feedback controller, a rst-order lead-lag feedforward controller (FFC), and nonlinear frictionand LH compensators. Brief description of the controlstrategy structure, tuning, and experimental vericationis given in the next subsections. More detailed elabora-tion can be found in Deur et al. (2004).Fig. 6. Electronic throttle control strategy.ARTICLE IN PRESS3.1. PID controller and feedforward controllerDesign of the linear control system with discrete-timePID controller is carried out in the continuous-timedomain. The sampler and the zero-order-hold element,as well as the time-differentiator used in the controllerderivative term, are approximated by a parasitic rst-order lag term with the time constant T5Tem(Tsampling time). The basic set of PID controllerparameters (for the region y4yLH) is calculated basedon the parameters Kpand Temof the IT1processmodel given by Eq. (7). The controller parametersare optimized according to the damping optimumanalytical design method (see Naslin, 1968; Za h Deur, 2001). Calculating the closed-loop system characteristic polynomial, and equating itwith the third-order damping optimum characteristicpolynomial:AsD32D3T3es3 D2T2es2 Tes 1 (9)yields the following simple equations for the controllerparameters:KR1KpTem TD22D3T2e, (10)TD D2Te1 C0D2D3TeTem TC18C19, (11)TI Te. (12)By setting the characteristic ratios D2and D3to theoptimal value 0.5, the resulting closed-loop system ischaracterized by the quasi-aperiodic step response withthe overshoot of 6% and the rise time of 1.8Te, andcorrespondingly with the gain margin, phase marginand critical frequency of 10 dB, 601 and 2.9/Te,respectively. The characteristic ratios D2and D3aredecreased here below the optimal value 0.5 (D2 0.37and D3 0.4), in order to provide the boundaryaperiodic step response of the control system. Theequivalent time constant of the closed-loop system Tedetermines the response time, and can be chosenarbitrarily to a value larger thanTe;min2D2D3T1 T=Tem. (13)Since the return spring is signicantly stiffer in theregion yoyLHthan in the region y4yLH(Fig. 2), thecontrol system tuned according to Eqs. (10)(12) wouldhave slower response in the region yoyLH: In order toprovide the same control performance for both regions,the return spring inuence must be taken into account,i.e. a second-order lag process model (3) must be usedinstead of the IT1model (7). The nal equations for theoptimal controller parameters for yoyLHcan conveni-D. Pavkovic et al. / Control Engineeringently be expressed as exact modications of the basicexpressions (10)(12):KRC0 KRC0DuDyC0, (14)TIC0 TI1 C0D22D3T2eTem TKpDuDyC0C18C19, (15)TDC0 T TDC0 T 1 C0D22D3T2eTem TKpDuDyC0C18C19C01,(16)where Du=DyC0is dened in Fig. 5. The change of PIDcontroller parameters with respect to operating region(yoyLHor y4yLH) is achieved by applying a simplegain-scheduling algorithm with bump-less transferincluded.The feedforward controller introduces a discrete-timezero zffinto the overall closed-loop transfer function,thus speeding up the response with respect to thereference signal. The zero is determined based on thezero-pole canceling approach:zff expC02T=Te. (17)3.2. Friction and LH compensationThe PID controller can provide favorable electronicthrottle behavior in the large-signal operating mode (forlarge changes of reference position yR). However, theelectronic throttle performance signicantly deterioratesin the small-signal operating mode due to the frictionand LH nonlinear effects. The experimental results inFig. 7a point out to unacceptable slow control systemresponse with respect to reference step change of 0.21.The slow response is a consequence of the stictioninuence. Similarly, a signicant response delay (astandstill interval) appears while the throttle passesthrough the nonlinear LH region (Fig. 8).In order to improve the control system performancein the small-signal operating mode, the PID controlleris extended with friction and LH compensators withoutputs ufcand uLHc, respectively (Fig. 6). Thecompensators have the same structure, because thefriction and LH nonlinearities have similar relay-typestatic curves and similar inuences to the controlsystem behavior (Fig. 4). Only one of the twocompensators is active at any time, depending onwhether the throttle is inside or outside the LH region.The LH compensator threshold parameter eLHistypically set to the double value of position measure-ment resolution DyC25 0:11:The compensators act as bangbang feedback con-trollers. Thus, they tend to provide fast and robustelimination of the control error C15: The magnitudes ofthe friction and LH bangbang controllers, ULHcandPractice 14 (2006) 121136 125USc, are set near the values of the LH and frictionARTICLE IN PRESSD. Pavkovic et al. / Control Engineering126voltages ULHand US:ULHc kLHULH,USc kSUS,kLH;kSC25 1. 18Therefore, the compensator action is limited to thecritical nonlinear small-signal operating mode only,without disturbing (destabilizing) the control system inthe large-signal operating mode. Namely, the overallcontrol strategy can be regarded as a dual controller,where the PID controller dominantly determines theclosed-loop system behavior in the large-signal operat-ing mode, and the nonlinear compensators are respon-sible for the small-signal operating mode.The main problem with the use of bangbangcontroller is a large level of noise in the commandedsignal u (the chattering effect), which can cause7a and b). More detailed results of experimentalFig. 8. Experimental ramp tracking responses of systems without andwith friction and LH compensator.Fig. 7. Experimental step responses of systems without (a) and withfriction compensator (b).verication of the control strategy are included in Deuret al. (2004),andPavkovic (2003).4. Inuence of process parameter variations4.1. Armature resistance variationsThe variations of armature resistance Ra KC01aaffectboth the parameters of linear and nonlinear parts of thecontrol system (Eqs. (1)(5). It is reasonable to assumethat the armature resistance variations do not exceed750% of the nominal value Ra0Ra20:5Ra0; 1:5Ra0C138:4.1.1. Linear control systemThe linear control system consists of the PIDcontroller and the linear process model given in Fig. 4,with mf 0 and ms KlKsy: Fig. 9 shows simulationstep responses of the linear control system for differentvalues of armature resistance. These step responsespoint out to small sensitivity of the linear control systemto armature resistance variations. This result has beenproven analytically by Pavkovic and Deur (2002). Thelinear control system sensitivity is somewhat larger inthe presence of feedforward controller (Pavkovic , 2003).4.1.2. Nonlinear control systemThe overall nonlinear control system is affected bythe armature resistance change through the change oftransmission and potentiometer wear, and excessivemotor losses. In order to avoid the chattering effect, aunit-gain rst-order low-pass lter is cascaded to thebangbang controller (Fig. 6). In the case of frictioncompensation, the lter use is also benecial from thestandpoint of avoiding the step response overshoots dueto the stiction dynamics. The lter time constants tfcandtLHcmay be made dependent on the absolute value ofthe control error C15 to obtain the best performance (seeDeur et al., 2004 for explanation of tuning the lookuptable tfcjC15j: It has been found, however, that evenconstant values tfcC25 70 ms and tLHcC25 15 ms give goodresults for the particular electronic throttle.The step responses in Fig. 7 and ramp responses inFig. 8 indicate that the friction and LH compensationresults in signicant reduction of stiction and LHstandstill intervals, thus making the responses similarto those of the linear system. Also, the important benetof friction compensation is fast establishing the one-bitlimit-cycle steady-state response (Fig. 7). Such abehavior is desirable in order to decrease the controlerror even below the position measurement resolution(0.11 here). It is important to note that the abovebenets are reached without any signicant increase ofthe noise magnitude in the commanded signal u (cf. Fig.Practice 14 (2006) 121136the breakaway voltage USand the LH voltage ULHnonlinear operating region (uemfC25 0), the chopper gainKchis cascaded to the armature gain Ka 1/Ra(Fig. 4).Thus the inuence of the battery voltage variations is thesame in this operating mode as the inuence of armatureresistance variations (Section 4.1).The response in the large-signal operating mode isexpected to be more sensitive to the battery voltagevariations than to variations of armature resistance,because the gain Kchappears outside the uemfdampingpath (Fig. 4). However, the battery voltage varies in anarrower range (typically 720% of the nominal batteryARTICLE IN PRESSPractice 14 (2006) 121136 127Fig. 9. Unit step responses of linear control system without feedfor-ward controller for different values of armature resistance.D. Pavkovic et al. / Control Engineering(Figs. 5 and 3):ULH ULH0Ka0Ka ULH0RaRa0, (19)US US0Ka0Ka US0RaRa0. (20)The non-adaptive control system with constantparameters USc kSUS0and ULHc kLHULH0; andvariable process parameters USand ULHwill obviouslyhave sub-optimal behavior if RaaRa0:This is conrmed by the simulation step responsesshown in Fig. 10. The step responses show thatovercompensation of nonlinear effects occurs for RaoRa0(the step response is faster with possible occurrence of anovershoot), while undercompensation of nonlinear effectsoccurs for Ra4Ra0(signicant standstill interval can beobserved). The LH compensator is more sensitive toarmature resistance variations than the friction compen-sator, primarily because ULH4US.4.2. Battery voltage variationsThe chopper gain Kchis proportional to the batteryvoltage Ubat(Pavkovic et al., 2003). In the low-speedFig. 10. Inuence of armature resistance variations on performance offriction compensation (a) and LH compensation (b).voltage Ubat0, compared with 750% armature resis-tance variations. Thus, the inuence of battery voltagevariations to the control system response in the large-signal operating mode is not emphasized either, asillustrated by simulation results in (Pavkovic which describes the desiredbehavior of the linear part of the electronic throttlecontrol system. In the case when the actual limp homeposition yLHis within the LH threshold jyLHC0yLH0jpC15LH; the throttle position response y is close tothe model response ym; i.e. the LH standstill interval isrelatively small and there is no overshoot in controlsystem response. However, when the actual LH positionexceeds the LH compensator threshold jyLHC0yLH0j4C15LH; a large discrepancy between the modelresponse and the real response is observed, particularlyat the actual LH position where the throttle is stuck fora considerable time. An undesirable overshoot can alsoFig. 11. Inuence of LH position variations.occur due to the inappropriate action of the LHcompensator (Fig. 11).5. Automatic tuning of control strategyThe electronic throttle control strategy in Section 3 isextended with an automatic tuning (auto-tuning)procedure, in order to deal with slow variations ofprocess parameters.5.1. Auto-tuner outlineThe schematic in Fig. 12 outlines how the auto-tunerworks. There are six characteristic phases of auto-tuneroperation, which are denoted in Fig. 12 by encirclednumbers and arrows. Each phase relates to either asingle point or a portion of the process static curve, andcan be executed in open loop (ol) or closed loop (cl). Fig.12 also shows which type of the commanded signal u orthe reference signal yRis applied in each phase.The auto-tuner determines the LH position yLHin theinitial phase 0 when u 0 is set. In phase 1 the throttle ispositioned to the upper edge of the static curve at y yLH; i.e. to the left most operating point of theapproximately linear operating region y4yLH_y40of the static curve (the nonlinear friction and LHinuences are overcome). At the beginning of phase 2, astep change of the commanded signal u is applied. Basedon the throttle position response the parameters ofdominant linear process dynamics are estimated. Usingthe estimated process parameters, the basic set of PIDcontroller parameters (for y4yLH) is determined at thebeginning of phase 3. The throttle is then brought(under the PID control) to the position y0; which issomewhat larger than the LH position yLH: In phase 4,the ramp change of the throttle position reference yRthrough the static curve region yoy0is commanded. Inthis way, the main parameters of the process static curveare estimated. Based on these estimates, nal tuning ofthe control strategy is carried out in phase 5.5.2. Process identificationARTICLE IN PRESSD. Pavkovic et al. / Control Engineering Practice 14 (2006) 121136128Fig. 12. Illustration of auto-tuning operations.The auto-tuning operation during the i
温馨提示:
1: 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
2: 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
3.本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
提示  人人文库网所有资源均是用户自行上传分享,仅供网友学习交流,未经上传用户书面授权,请勿作他用。
关于本文
本文标题:发动机怠速PID控制研究【论文】
链接地址:https://www.renrendoc.com/p-10109475.html

官方联系方式

2:不支持迅雷下载,请使用浏览器下载   
3:不支持QQ浏览器下载,请用其他浏览器   
4:下载后的文档和图纸-无水印   
5:文档经过压缩,下载后原文更清晰   
关于我们 - 网站声明 - 网站地图 - 资源地图 - 友情链接 - 网站客服 - 联系我们

网站客服QQ:2881952447     

copyright@ 2020-2024  renrendoc.com 人人文库版权所有   联系电话:400-852-1180

备案号:蜀ICP备2022000484号-2       经营许可证: 川B2-20220663       公网安备川公网安备: 51019002004831号

本站为文档C2C交易模式,即用户上传的文档直接被用户下载,本站只是中间服务平台,本站所有文档下载所得的收益归上传人(含作者)所有。人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对上载内容本身不做任何修改或编辑。若文档所含内容侵犯了您的版权或隐私,请立即通知人人文库网,我们立即给予删除!