无人机专业英语 第二版 课件 4.1 Flight Dynamics of UAV

EnglishforUnmannedaerialvehicle无人机专业英语Project4:FlightDynamicsofUAV-------Fixed-wingdroneAerodynamicforcesControlsurfacesAileronsElevatorsRudderFlapsswivel [ˈswɪvl]vt.（使）旋转;在枢轴上转动perpendicular[ˌpɜ:pənˈdɪkjələ(r)]adj.垂直的，成直角的sideslip['saɪdslɪp]n.侧滑profile [ˈprəʊfaɪl]n.侧面;外形，轮廓airfoil [ˈeəfɔɪl]n.翼面deflect [dɪˈflekt]vt.使弯曲;偏转camber [ˈkæmbə(r)]n.拱形versatile[ˈvɜ:sətaɪl]adj.多功能的;多用途的hinge[hɪndʒ]n.铰链NewWordsswash[swɒʃ]platen.倾斜盘gearbox [ˈgɪəbɒks]n.变速箱;齿轮箱;变速器collectivepitch[kəˈlektivpitʃ]n.总距rod[rɒd]n.杆，拉杆cyclicpitch[ˈsaɪklɪkpitʃ]n.周期桨距bearing [ˈbeərɪŋ]n.轴承NewWordsFlightdynamicsofUAVreferstothestudyoftheperformance,stability,andcontrolofunmannedaerialvehicles.Itisconcernedwithhowforcesactingonthevehicleinfluenceitsspeedandattitudewithrespecttotime.无人机飞行动力学研究的是无人机的性能、稳定性和控制。它关心的是作用在无人机上的力如何影响其速度和姿态。Part0----WhatisFlightDynamicsThethreecriticalflightdynamicsparametersoffixed-wingdronearetheanglesofrotationinthreedimensionsaboutthevehicle‘scenterofmass,knownaspitch,rollandyaw.固定翼无人机三个关键的飞行动力参数是以飞机重心为坐标原点的三维坐标系下的旋转角，即我们熟知的俯仰角、横滚角和偏航角。Themostcommonaeronauticalconventiondefinestherollasactingaboutthelongitudinalaxis,positivewiththestarboard(right)wingdown.Theyawisabouttheverticalbodyaxis,positivewiththenosetostarboard.Pitchisaboutanaxisperpendiculartothelongitudinalplaneofsymmetry,positivenoseup.最通常的航空惯例定义横滚轴为飞机的纵轴，向右滚转为正方向；偏航轴为飞机立轴，向右偏航为正；俯仰轴垂直于飞机纵向对称面，飞机抬头为正。Part1----Fixed-wingdroneAfixed-wingdroneincreasesordecreasestheliftgeneratedbythewingswhenitpitchesnoseupordownbyincreasingordecreasingtheangleofattack(AOA).Therollangleisalsoknownasbankangleonafixed-wingaircraft,whichusually"banks"tochangethehorizontaldirectionofflight.Anaircraftisusuallystreamlinedfromnosetotailtoreducedragmakingittypicallyadvantageoustokeepthesideslipanglenearzero.当飞机俯仰时，其攻角会增加或者减少，带来的是通过机翼产生的升力的增加或者减少。横滚角也叫倾斜角，一般是通过倾斜来改变飞行的水平方向。飞机从机头到机尾通常呈流线型，这样可以减少阻力，通常有利于保持侧滑角接近于零。Part1----Fixed-wingdroneEssentiallythereare4aerodynamicforcesthatactonanairplaneinflight;thesearelift,drag,thrustandweight.飞机在飞行中主要受到4个力：升力、阻力、推理和重力。Part2----AerodynamicforcesInsimpleterms,dragistheresistanceofairmoleculeshittingtheairplane(thebackwardforce),thrustisthepoweroftheairplane'sengine(theforwardforce),liftistheupwardforceandweightisthedownwardforce.So,forairplanestoflyandstayairborne,thethrustmustbegreaterthanthedragandtheliftmustbegreaterthantheweight.简单来说，阻力是空气分子撞击飞机产生的阻滞力；推力是飞机发动机的动力；升力是向上的力；重力是向下的力。因此，飞机要飞起来并维持飞行状态，推力必须大于阻力，并且升力必须大于重力。Acrosssectionofatypicalairplanewingshowthetopsurfacetobemorecurvedthanthebottomsurface.Thisshapedprofileiscalledan'airfoil'andtheshapeexistsbecauseit'slongbeenproven(sincethedawnofflight)thatanairfoilgeneratessignificantlymoreliftthanopposingdrag.典型飞机机翼的横截面是上表面比底部更弯曲。这种形状的翼型称作一种翼面，而且已经证明了这种形状的机翼产生的升力比飞行阻力要多得多。Part2----AerodynamicforcesDuringflight,airnaturallyflowsoverandbeneaththewingandisdeflectedupwardsoverthetopsurfaceanddownwardsbeneaththelowersurface.Anydifferenceindeflectioncausesadifferenceinairpressure('pressuregradient')andbecauseoftheairfoilshapethepressureofthedeflectedairislowerabovetheairfoilthanbelowit.Asaresult,thewingis'pushed'upwardsbythehigherpressurebeneath.在飞行中，空气自然地流过机翼上下表面，并且沿着上下表面弯曲。弯曲上的任何改变会引起空气压力的改变，并且由于翼面形状特性，翼面上表面空气压力比下表面低。结果是，机翼被下表面高压空气向上托起。Part2----AerodynamicforcesLocatedonthetrailingedge(rear)ofthewing,theaileronscontroltheairplane‘srollaboutitslongitudinalaxis.Eachaileronmovesatthesametimebutinoppositedirectionsi.e.whentheleftaileronmovesup,therightaileronmovesdownandviceversa.位于机翼的后缘，副翼控制飞机沿飞机纵轴滚转的动作。每一个同时动作，但是转动方向相反，例如，当左副翼朝上，则右副翼朝下，反之亦然。Part3----AileronsThismovementcausesaslightdecreaseinliftonthewingtipwiththeupwardmovingaileron,whiletheoppositewingtipexperiencesaslightincreaseinlift.Becauseofthesesubtlechangesinlift,theairplaneisforcedtorollintheappropriatedirectioni.e.whentheoperatormovesthecontrolsticktotheleftonthetransmitter,theleftaileronwillriseandtheairplanewillrollleftinresponsetothechangeinliftoneachwing.向上的副翼会引起翼梢上升力的轻微减少，与之相对的翼梢上的升力则略微增加。由于升力的轻微改变，飞机就能朝合适的方向进行滚转。当操控者操控遥控器上的控制杆向左，左副翼向上，飞机上机翼的升力将会改变，飞机将向左滚转。Part3----AileronsTheelevatorsarelocatedontherearhalfofthetailplane,orhorizontalstabiliser.Thejobofthetailplaneistogenerateadownwardforcetocounteractthenaturalnose-divingtendencyofplanes,whichhappensasaresultofthenaturalforcesthataregeneratedaboutaplane'sCentreofGravityandCentreofLift.升降舵位于尾翼（水平安定面）的后半部分。尾翼的作用是产生一个下洗力来对抗飞机自然地抬头趋势，这些自然力作用在飞机上的结果是形成了重心和压力中心。Part4----ElevatorsTheruddermakesuptherearportionoftheverticalstabiliser,orfin.Whentheoperatormovestheruddersticktotheleftonthetransmitter,theruddermovestotheleft,whiledepressingtheruddersticktotherightdeflectstheruddertotheright.方向舵位于垂直安定面的后部。当操控者在遥控器上向左打方向杆，方向舵朝左偏，而向右压方向杆，方向舵会朝右偏转。Part4----RudderEssentially,youcanthinkofafinasaverticalwing.Theairflowingoveritandtherudderactsinexactlythesamewayasitdoesflowingoverawingandaileron-excepttheforcesareverticalandnothorizontal.本质上，你可以把垂直尾翼看做是垂直的机翼。流过它的空气和方向舵作用的方式和副翼及机翼与空气作用的方式是一样的，只不过现在的空气动力是垂直的而不是水平的。Deflectingtheruddertotheleftincreasestheairpressureontheleftsideofthefinandrudder,andsothewholebackendoftheplaneispushedacrosstotheright,thusyawingthenosetotheleft.方向舵向左偏转使得垂直尾翼左侧空气压力增加，所以飞机的整个尾部被推向右侧，这样机头就向左偏转。Part4----RudderFlapsarelocatedonthetrailingedgeofeachwing,usuallybetweenthefuselageandtheailerons,andextenddownward(andoftenoutward)fromthewingwhenputintouse.Thepurposeoftheflapsistogeneratemoreliftatslowerairspeed,whichenablestheairplanetoflyatagreatlyreducedspeedwithalowerriskofstalling.Whenextendedfurtherflapsalsogeneratemoredragwhichslowstheairplanedownmuchfasterthanjustreducingthrottle.襟翼位于机翼的后缘，通常介于机身和副翼之间，并且在实际使用中，一般是向外伸出。襟翼的目的是在较低的速度下产生更多的升力，这使得飞机能在大为减少的速度下飞行，且失速风险较低。但是进一步伸出襟翼也能产生更多阻力，这会比采用减少油门的方法更快地使飞机减速。Part4----FlapsBESTREGARDSTOALLOFYOU!THANKS!EnglishforUnmannedaerialvehicle无人机专业英语Project

4:FlightDynamicsofUAV-------unmannedhelicopterMechanicalpartsStayintheairHoveringSteeringswivel [ˈswɪvl]vt.（使）旋转;在枢轴上转动perpendicular[ˌpɜ:pənˈdɪkjələ(r)]adj.垂直的，成直角的sideslip['saɪdslɪp]n.侧滑profile [ˈprəʊfaɪl]n.侧面;外形，轮廓airfoil [ˈeəfɔɪl]n.翼面deflect [dɪˈflekt]vt.使弯曲;偏转camber [ˈkæmbə(r)]n.拱形versatile[ˈvɜ:sətaɪl]adj.多功能的;多用途的hinge[hɪndʒ]n.铰链NewWordsswash[swɒʃ]platen.倾斜盘gearbox [ˈgɪəbɒks]n.变速箱;齿轮箱;变速器collectivepitch[kəˈlektivpitʃ]n.总距rod[rɒd]n.杆，拉杆cyclicpitch[ˈsaɪklɪkpitʃ]n.周期桨距bearing [ˈbeərɪŋ]n.轴承NewWordsEachrotorbladeisconnectedtothehubandrotatingmastbyafeatheringhinge,whichallowsittoswivel.Apitchlink(ashortrod)attachedtoeachbladecantiltittoasteeperorshallowerangleaccordingtothepositionoftherotatingupperswashplate,whichspinsonbearingsaroundthestaticlowerswashplate.That'showachopperhoversandsteers.Thetwoswashplatesaremovedupanddownortiltedtothesidebytheoperator'scyclicandcollectivecontrols.每个旋转叶片通过水平铰链连接到桨毂和旋翼轴，这使得叶片可以绕轴旋转。连接到每个叶片的节距连杆（短杆）可根据旋转的上倾斜盘的位置使叶片倾斜到更陡或更浅的角度，旋转的上倾斜盘在静止的下旋转斜盘周围的轴承上旋转。这就是直升机悬停和操纵的方式。两个旋转斜盘通过操控者的周期变距和总距控制进行上下移动或向侧面倾斜。Part0----MechanicalpartsTherotorispoweredbyadriveshaftconnectedtoatransmissionandgearbox.Thesametransmissionpowersasecond,longerdriveshaftconnectedtoagearboxthatspinsthetailrotor.Thepowerfrombothrotorscomesfromoneortwoengines.旋翼由连接到减速器的驱动轴提供动力。同样的减速器驱动第二个较长的驱动轴该驱动轴连接一个齿轮箱，驱动尾桨旋转。主旋翼和尾旋翼的动力来自一个或两个发动机。Part0----MechanicalpartsAstheyshootforwards,theirwingschangethepressureanddirectionoftheoncomingair,forcingitdownbehindthemandpoweringthemupintothesky:aplane'senginesspeeditforward,whileitswingsflingitup.Thebigproblemwithaplaneisthatlotsofairhastoraceacrossitswingstogenerateenoughlift;thatmeansitneedslargewings,ithastoflyfast,anditneedsalongrunwayfortakeoffandlanding.当固定翼飞机快速向前时，机翼改变迎来空气的压力和方向，使空气向下后方流去，从而使得飞机升上天：飞机发动机使飞机加速向前，从而机翼产生升力以抬升飞机。固定翼飞机最大的问题是必须使得大量的空气流过机翼才能产生足够的升力；意味着需要大机翼，并且必须飞得快，也就需要长跑道用来起飞和降落。Part1----StayintheairHelicoptersalsomakeairmoveoverairfoilstogeneratelift,butinsteadofhavingtheirairfoilsinasinglefixedwing,theyhavethembuiltintotheirrotorblades,whichspinaroundathighspeed(roughly500RPM,revolutionsperminute).Therotorsarelikethinwings,"running"onthespot,generatingamassivedowndraftofairthatblowsthehelicopterupward.Withskillfulpiloting,ahelicoptercantakeofforlandvertically,hoverorspinonthespot,ordriftgentlyinanydirection—andyoucan'tdoanyofthatinaconventionalplane.直升机同样使得空气流过翼面产生升力，但是比之固定翼是单一固定的机翼，直升机则是旋转的机翼，转速可高达500转/分钟。旋翼就像薄机翼，围绕一个点旋转，产生大量的下洗气流，从而抬升直升机。Part1----StayintheairIftheliftisgreaterthantheweight,thehelicopterclimbs;ifit‘slessthantheweight,thehelicopterfalls.Whentheliftandtheweightareexactlyequal,thehelicopterhoversinmid-air.Theoperatorcanmaketherotorbladesgeneratemoreorlessliftusingacontrolcalledthecollectivepitch,whichincreasesordecreasestheangle("pitch")thatallthebladesmaketotheoncomingairastheyspinaround.Fortakeoff,thebladesneedtomakeasteepangletogeneratemaximumlift.操控者可以通过总距控制杆是的旋翼产生更多或更少的升力，这是通过控制杆增加或者减少叶片相对气流的角度来实现的。飞机要起飞，叶片需要大角度来产生最大的升力。Part2----HoveringThecollectivepitchcontrolchangestheangle(orpitch)ofeachoftherotorbladesbythesameamountatthesametime(greenarrows)—inotherwords,collectively.Ifthebladesmakeasteeperangle,theygeneratemoreliftsotheentirecraftmovesstraightupward(orangearrow).Part2----HoveringThebladeshaveshortverticalrods(pitchlinks)attachedtothemthatareconnectedtoarotatingmetaldisccalledaswashplate,abitlowerdownthemast.Thisswashplateslidesonbearingsaroundasecond,similarplatedirectlyunderneaththatdoesn'trotate.Whentheoperatormovesthecollectiveoneway,bothswashplatesmoveupward,pushinguponthepitchlinksthattilttherotorbladestoasteeperangle.桨叶连有短而垂直的杆，这些支撑杆连接到旋转的称为倾斜盘的金属盘上，倾斜盘在主轴下方一点点距离。倾斜盘可以在轴承上滑动，且轴承下方也有一个相似的盘，但下方的盘不旋转。当操控者操控总距杆到一个方向，上下倾斜盘都向上运动，推动支撑杆，支撑杆带动旋翼，使得旋翼倾斜更大的角度。Part2----HoveringTheydothisbyswivelingbackandforth(feathering)astheyrotate,so,forexample,theymakeasteeperanglewhenthey'reontheleftsideofthecraftthanwhenthey'reontheright.Thatmeanstheygeneratemoreliftontheleft,tiltingthecraftovertotherightandsteeringitinthatdirection.直升机转向通过旋翼来回地旋转实现，例如，当旋翼位于机身左侧时，其倾斜角比位于机身右侧时更大。这意味着左侧产生更大的升力，从而使得机身向右倾斜，并向那个方向驶去。Part3----SteeringTheoperatorsteerslikethisusingasecondlevercalledthecyclicpitch,similartoajoystick,whichmakesthebladesswivelastheycyclearound.Thecyclicpitchcontrolchangestheangleofselectiverotorbladesastheyspin,so(inthiscase)whicheverbladeisontheleftalwaysproducesslightlymorelift,whiletheoppositebladealwaysproducesslightlylesslift.Thatmeansmoreliftisproducedontheleftsideofthehelicopter,sotheoveralllift(orangearrow)istiltedtotheright,steeringtheentirehelicopterinthatdirection.操控者通过一个叫做周期变距杆来控制直升机转向，变距杆外形和摇杆类似，当叶片旋转时可以控制叶片转动一定的角度。当叶片旋转时，周期变距改变所选旋翼的角度，因此只要在左侧的叶片产生多一点升力，而对向的叶片总是产生少一点推力。这意味着飞机左侧升力大些，总的升力就向右倾斜，使得直升机向那个方向驶去。Part3----SteeringTheingeniousswashplatemechanismtranslatestheoperator'scommandsintoappropriatemovementsoftherotorblades.youcanseeasimplifiedviewoftheswashplatemechanism.Therearetwodiscsatthetopoftherotormast,anupperone(red)thatrotatesonballbearings(orange)aroundalowerone(blue)thatdoesn'trotateatall.Fourpitchlinks(green)connecttheupperswashplatetotherotorblades.设计精巧的旋转斜盘机构将操控者的命令转换为转子叶片的合适运动。旋翼轴顶部有两个圆盘，上边圆盘（红色）在滚珠轴承（橙色）上围绕下边圆盘（蓝色）旋转，而下边的圆盘根本不旋转。四个变桨连杆（绿色）将上斜盘连接到转子叶片上。Part3----SteeringSupposetheoperatorwantstoflytotheright.First,thecommandmovesthecyclictotheright.Thattiltsbothswashplatesovertotheright.Astherotorbladesrotate,thetiltedswashplatesforcethepitchlinksupwhenthey'reontheleftanddownwhenthey'reontheright.Thatmakeseachrotorbladetilttoasteeperanglewhenit'sontheleftandashalloweranglewhenit'sontheright.Thisproducesmoreliftontheleft,steeringthechoppertotheright.这将会使倾斜盘整体向右倾斜。当旋翼叶片旋转时，倾斜盘倾斜使得支撑杆在左侧时抬升，在右侧降低。这使得每个转子叶片转到左边时倾斜角度更抖，在右边时则更浅些。最终会使得左侧升力更大，从而操控直升机向右飞行。Part3----SteeringBESTREGARDSTOALLOFYOU!THANKS!EnglishforUnmannedaerialvehicle无人机专业英语四旋翼飞行器飞行动力学Project

4:Quadcopter——TheFlightdynamicsoffset[ˈɒfset]cumulative[ˈkju:mjələtɪv]spin [spɪn]aerodynamic[ˌeərəʊdaɪ'næmɪk]schematic[ski:ˈmætɪk]yield [ji:ld]diametrically[ˌdaɪəˈmetrɪkli] coaxial [kəʊ'æksɪəl] alike [əˈlaɪk] NewWords

抵消;补偿;累积的;渐增的;追加的;快速旋转;眩晕;空气动力（学）的;纲要的;示意的;严谨的;有章法的;屈服，投降;生产;获利;不再反对;作为直径地，直接地;同轴的，共轴的;同样地;两者都，同样地;类似于;TheFlightdynamicsEachrotorproducesbotha

thrust

and

torque

aboutitscenterofrotation,aswellasa

dragforce

oppositetothevehicle'sdirectionofflight.Ifallrotorsarespinningatthesame

angularvelocity,withrotorsoneandthreerotatingclockwiseandrotorstwoandfourcounterclockwise,thenetaerodynamictorque,andhencetheangularaccelerationaboutthe

yawaxis,isexactlyzero,whichmeanthereisnoneedforatailrotorasonconventionalhelicopters.Yawisinducedbymismatchingthebalanceinaerodynamictorques(i.e.,byoffsettingthecumulativethrustcommandsbetweenthecounter-rotatingbladepairs).Part1----theFlightDynamicsTheFlightdynamics

每个转子产生一个推力和绕其中心旋转的扭矩，以及与飞机飞行方向相反的阻力。如果所有的转子以同一角速度旋转，并且转子一和三顺时针旋转，转子二和四逆时针旋转，净空气动力矩，因此绕偏航轴的角加速度为零，这意味着无需像常规直升机那样需要一尾桨。偏航是由空气动力转矩不平衡引起的（即通过抵消反向旋转的叶片对之间的累积推力命令）。

Thisshowsthedirectionoftravelforeachpropellerrespectivetothedirectionoftravel.Theredpropellersaremovingclockwisewhilethebluepropellersaremovingcounterclockwise.Schematicofreactiontorquesoneachmotorofaquadcopteraircraft,duetospinningrotors.Rotors1and3spininonedirection,whilerotors2and4spinintheoppositedirection,yieldingopposingtorquesforcontrol.Part1----theFlightDynamics由于转子旋转，在每一电机上反作用力矩示意图。转子1和3旋转在一个方向上，而转子2和4以相反的方向旋转，这样产生相反的控制扭矩。

Part1----theFlightDynamicsAquadrotorhoversoradjustsitsaltitudebyapplyingequalthrusttoallfourrotors.Aquadrotoradjustsitsyawbyapplyingmorethrusttorotorsrotatinginonedirection.

Part1----theFlightDynamicsAquadrotoradjustsitspitchorrollbyapplyingmorethrusttoonerotorandlessthrusttoitsdiametricallyoppositerotor.TheCoaxialconfigurationInordertoallowmorepowerandstabilityatreducedweight,aquadcopter,likeanyother

multirotor

canemploya

coaxialrotor

configuration.Inthiscase,eacharmhastwomotorsrunninginoppositedirections(onefacingupandonefacingdown).Part1----theFlightDynamics为了在减重情况下，有更多的动力并且更加稳定，像任何其他多旋翼飞机，四轴飞行器可以用同轴转子配置。在这种情况下，每个机臂有两个运行在相反方向的电机（一个朝上，一个朝下）。Mechanicalstructure

Themainmechanicalcomponentsneededforconstructionaretheframe,

propellers

(eitherfixed-pitch

orvariable-pitch),andtheelectricmotors.Forbestperformanceandsimplestcontrolalgorithms,themotorsandpropellersshouldbeplace