壓力傳感器外文翻譯

1、-WORD 格式-WORD 格式-可編輯-專業(yè)資料-完整版學(xué)習(xí)資料分享-壓力傳感器合理進(jìn)行壓力傳感器的誤差補(bǔ)償是其應(yīng)用的關(guān)鍵。壓力傳感器主要有偏移量誤差、靈敏度誤差、線性誤差和滯后誤差，本文將介紹這四種誤差產(chǎn)生的機(jī)理和對測試結(jié)果的影響，同時將介紹為提高測量精度的壓力標(biāo)定方法以及應(yīng)用實例。目前市場上傳感器種類豐富多樣，這使得設(shè)計工程師可以選擇系統(tǒng)所需的壓力傳 感器。這些傳感器既包括最基本的變換器，也包括更為復(fù)雜的帶有片上電路的高集成 這是保證傳感器滿足設(shè)計和應(yīng)用要求的重要步驟。在某些情況下，補(bǔ)償還能提高傳感 器在應(yīng)用中的整體性能。本文以摩托羅拉公司的壓力傳感器為例，所涉及的概念適用于各種壓力傳感

2、器的設(shè)計應(yīng)用。摩托羅拉公司生產(chǎn)的主流壓力傳感器是一種單片壓阻器件，該器件具有 3 類：基本的或未加補(bǔ)償標(biāo)定；有標(biāo)定并進(jìn)行溫度補(bǔ)償；有標(biāo)定、補(bǔ)償和放大。偏移量、范圍標(biāo)定以及溫度補(bǔ)償均可以通過薄膜電阻網(wǎng)絡(luò)實現(xiàn)，這種薄膜電阻網(wǎng)絡(luò)在封裝過程中采用激光修正。該傳感器通常與微控制器結(jié)合使用，而微控制器的嵌入軟件本身建立了傳感器數(shù)學(xué)模型。微控制器讀取了輸出電壓后，通過模數(shù)轉(zhuǎn)換器的變換，該模型可以將電壓量轉(zhuǎn)換為壓力測量值。傳感器最簡單的數(shù)學(xué)模型即為傳遞函數(shù)。該模型可在整個標(biāo)定過程中進(jìn)行優(yōu)化，并且模型的成熟度將隨標(biāo)定點的增加而增加。從計量學(xué)的角度看，測量誤差具有相當(dāng)嚴(yán)格的定義：它表征了測量壓力與實際壓力之間的差

3、異。而通常無法直接得到實際壓力，但可以通過采用適當(dāng)?shù)膲毫?biāo)準(zhǔn)加以估計，計量人員通常采用那些精度比被測設(shè)備高出至少 10 倍的儀器作為測量標(biāo)準(zhǔn)。由于未經(jīng)標(biāo)定的系統(tǒng)只能使用典型的靈敏度和偏移值將輸出電壓轉(zhuǎn)換為壓力，測得的壓力將產(chǎn)生如圖 1 所示的誤差。這種未經(jīng)標(biāo)定的初始誤差由以下幾個部分組成：光調(diào)節(jié)修正的變化將產(chǎn)生偏移量誤差。靈敏度誤差，產(chǎn)生誤差大小與壓力成正比。如果設(shè)備的靈敏度高于典型值，靈敏度誤差將是壓力的遞增函數(shù)（見圖1）是壓力的遞減函數(shù)。該誤差的產(chǎn)生原因在于擴(kuò)散過程的變化。的物理非線性，但對于帶放大器的傳感器，還應(yīng)包括放大器的非線性。線性誤差曲線可以是凹形曲線，也可以是凸形曲線。的機(jī)械剛度

4、。一般只需在壓力變化很大的情形中考慮滯后誤差。標(biāo)定可消除或極大地減小這些誤差，而補(bǔ)償技術(shù)通常要求確定系統(tǒng)實際傳遞函數(shù)的參數(shù)，而不是簡單的使用典型值。電位計、可調(diào)電阻以及其他硬件均可在補(bǔ)償過程中采用，而軟件則能更靈活地實現(xiàn)這種誤差補(bǔ)償工作。稱為自動歸零。偏移量標(biāo)定通常在零壓力下進(jìn)行，特別是在差動傳感器中，因為在標(biāo)稱條件下差0讀取系統(tǒng)，用以測量其在環(huán)境大氣壓力條件下的標(biāo)定壓力值，要么需要獲取期望壓力的壓力控制器。差動傳感器的零壓力標(biāo)定非常精確，因為標(biāo)定壓力嚴(yán)格為0。另一方面，壓力不為0 時的標(biāo)定精確度取決于壓力控制器或測量系統(tǒng)的性能。選擇標(biāo)定壓力標(biāo)定壓力的選取非常重要，因其決定了獲取最佳精度的壓力

5、范圍。實際上，經(jīng)過標(biāo)定后實際的偏移量誤差在標(biāo)定點處最小并一直保持較小的值。因此，標(biāo)定點必須根據(jù)目標(biāo)壓力范圍加以選擇，而壓力范圍可以不與工作范圍相一致。為了將輸出電壓轉(zhuǎn)換為壓力值，由于實際的靈敏度往往是未知，因此在數(shù)學(xué)模型中通常采用典型靈敏度進(jìn)行單點標(biāo)定。紅色曲線表示進(jìn)行偏移量標(biāo)定（PCAL=0）后的誤差曲線，可以發(fā)現(xiàn)誤差曲線相對于表示標(biāo)定前誤差的黑色曲線產(chǎn)生了垂直偏移。這種標(biāo)定方法與一點標(biāo)定法相比要求更為嚴(yán)格，實現(xiàn)成本也更高。然而與一點標(biāo)定法相比，該方法可顯著提高系統(tǒng)的精度，因為該方法不僅標(biāo)定了偏移量，還標(biāo)定了傳感器的靈敏度。因此在誤差計算中可以使用靈敏度實際值，而非典型值。綠色曲線表示精度提

6、高。在這里，標(biāo)定是在0 500 兆巴（滿標(biāo)度）某些應(yīng)用中要求在整個壓力范圍內(nèi)保持較高的精確度。在這些應(yīng)用中，可以采用 （在兩個標(biāo)定點之間）的兩級標(biāo)定完全一樣。三點標(biāo)定如前所述，線性誤差具有一致的形式，且誤差曲線符合二次方程的曲線，具有可預(yù)測的大小和形狀。對于未采用放大器的傳感器更是如此，因為傳感器的非線性從本質(zhì)上是基于機(jī)械原因（這是由硅片的薄膜壓力引起）。線性誤差特性的描述可以通過計算典型實例的平均線性誤差，確定多項式函數(shù)（a2+bx+c）的參數(shù)而得到。確定了 a、b 和 c 后得到的模型對于相同類型的傳感器都是有效的。該方法能在無需第 3 個標(biāo)定點的情況下有效地補(bǔ)償線性誤差。MPX2300

7、是一種主要應(yīng)用于血壓測量的溫度補(bǔ)10 3 虛線所示。該誤差補(bǔ)償方法只需兩點標(biāo)定即可將低成本傳感器改進(jìn)為高性能器件（誤差小于滿標(biāo)度的 0.05%）。當(dāng)然設(shè)計工程師要根據(jù)實際應(yīng)用的精確度要求，選擇最適合的標(biāo)定方法，此外還需要考慮系統(tǒng)成本。由于有多種集成度和補(bǔ)償技術(shù)可供選擇，設(shè)計工程師可根據(jù)不同的設(shè)計要求選擇適當(dāng)?shù)姆椒?。Pressure sensorsReasonable pressure sensor error compensation is the key to its application.Pressuresensorsaremainlyoffseterror,sensitivityerr

8、or,linearerrorandlagerrors, thepaperwillintroducethefourerrorsonthemechanismandtheeffectsofthetest results,willbepresentedatthesametimetoimprovethemeasurementaccuracyof pressurecalibrationmethodandapplicationexamples.Currently on the market a variety of sensor types, which allows design engineerscan

9、choosethepressuresensorsystem.Thesesensorsnotonlyinclude themostbasicconverter,butalsomorecomplexcircuitswithon-chip,highly integratedsensor.Becauseofthesedifferences,thedesignengineermustbe enoughasfaraspossiblecompensationofpressuresensormeasurementerror, which is to ensure that the design and app

10、lication of sensors to meet the requirementsofanimportantstep.Insomecases,compensationcanincreasethe sensorintheapplicationoftheoverallperformance.BasedonMotorolaspressuresensorasanexample,theapplicationofconceptinvolvedinthedesignofavarietyofpressuresensorapplications.Motorolamainstreamproductionpr

11、essurepiezoresistivesensorisamonolithic device, the device has 3categories:Basic calibration or withoutcompensation;Therearecalibrationandtemperaturecompensation;Therearecalibration,compensationandamplification.Offset,thescopeofcalibrationandtemperaturecompensationcanbethrough thethinfilmresistornet

12、works,thethinfilmresistornetworksintheprocessoflaser packageamendments.The sensor is usually used in conjunction with the micro-controller, and microcontrollerembeddedsoftwareitself,establishedamathematicalmodelofsensor.MicrocontrollerreadstheoutputvoltagethroughtheADCconversion,the modelcanbeconver

13、tedtothepressureofthevolumeofvoltagemeasurements.Thesimplestsensoristhetransferfunctionofthemathematicalmodel.modelcalibrationovertheentireoptimizationprocessandmaturitymodelwillbe marked with the fixed-pointincrease.From the point of view of metrology, measurement error has a very strict definition

14、: it is characterized by measurement of pressure and the difference between theactualpressure.Usuallycannotdirectlybetheactualpressure,butthroughthe useofappropriatecriteriatoestimatethepressure,themeasurementaccuracyareusuallymorethanthosemeasuredusingequipmentatleast10timeshigherthaninstrument as

15、a measurementstandard.Withoutcalibrationofthesystemasaresultcanonlyusethetypicalvaluesensitivityandoffsettheoutputvoltageisconvertedtopressure,thepressure measuredwillhaveamarginoferrorasshowninFigure1.This initial error without calibration by the following components:offseterror.Asthepressureinthee

16、ntirerangeofverticalshifttomaintaina constant, so the proliferation and laser conditioning converter changes the amendment would have offseterror.Thesensitivityoferror,resultinginerrorsindirectproportiontothesizeand pressure.Ifthedeviceishigherthanthetypicalvalueofthesensitivity,thesensitivity ofthe

17、errorwillbeincrementalpressurefunction(seeFigure1).Ifthesensitivityis lowerthanthetypicalvalue,thenthesensitivityoftheerrorwillbedecreasing functionofpressure.Thecauseoftheerrordiffusionprocessistochange.LinearityError.Thisisaninitialerrorfactorlessaffected,theerroristhe causeofthephysicalnon-linear

18、silicon,butwiththesensoramplifier,shouldalso includenon-linearamplifier.Linearerrorcurvecanbeconcavecurve,itcouldbeconvexcurve.LagError:Inmostcases,thelagerrorcanbeignoredcompletely,because siliconhasahigherdegreeofmechanicalstiffness.Changesingeneraljustalotof pressure to consider the case of hyste

19、resiserror.Calibration can eliminate or greatly reduce these errors, and compensation techniqueisusuallyrequiredtoidentifytheparametersoftheactualtransferfunction, rather than simply the use of typical values. Potentiometer, adjustable resistance, andotherhardwarecanbeusedinthecompensationprocess,wh

20、ilethesoftwareis abletoachievemoreflexibilityintheworkofthiserrorcompensation.CalibrationmethodthatcaneliminatethetransferfunctionagainsttheAgency tocompensatetheoffsetdrifterror,suchastheauto-zerocalibrationmethod.Offsetzerocalibrationisusuallycarriedoutunderpressure,especiallyinthe differentialsen

21、sor,becauseundertheconditionsofthenominaldifferentialpressure isusually0.Forpuresensoroffsetcalibrationwillbedifficult,becauseiteithertoreadapressuresystemtomeasuretheatmosphericpressureintheenvironment undertheconditionsofthecalibrationofpressureorneedtoobtainthepressureof expectations of the press

22、urecontroller.Zerodifferentialpressuresensorisveryaccuratecalibration,becausethe pressureofstrictdemarcationis0.Ontheotherhand,thepressureof0:00isnotthe accuracyofthecalibrationdependsonthepressurecontrollerortheperformance measurementsystem.Choice of calibration pressureCalibrationisveryimportantse

23、lectionpressure,whichdeterminestheaccuracy to obtain the best pressure range. In fact, after calibration offset actual standard fixed-pointerrorintheDepartmentandhasbeentomaintainasmallerminimum value.Therefore,thereferencepointsmustbeinaccordancewiththescopeofthetargetselectionpressure,andpressurer

24、angecannotbeconsistentwiththescopework.Inordertoconvertthepressureoftheoutputvoltagevalue,usuallyasaresult oftheactualsensitivityisunknown,andthereforethemathematicalmodelusedfortypical single-point calibrationsensitivity.Saidthattheredcurvecalibrationoffset(PCAL=0)aftertheerrorcurve,the errorcanbef

25、oundthatcalibrationcurverelativetotheblackbeforetheerrorhadvertical offsetcurve.This calibration method and calibration method that is more stringent requirements to achieve a higher cost. However, compared with the calibration themethodcansignificantlyimprovetheaccuracyofthesystem,becausethe method

26、isnotonlyanoffsetcalibration,thecalibrationofthesensorsensitivity.Therefore,thecalculationerrorcanbeusedintheactualvalueofsensitivity,andatypicalvalues.Thatimprovetheaccuracyofthegreencurve.Here,calibrationistrillionbar (full scale) conditions. As the marked point on the error close to 0, so the pre

27、ssureofexpectationstobethesmallestrangeofmeasurementerror,thecorrect set of these points, it is particularlyimportant.Someapplicationsrequirethepressureinthewholerangeofhighaccuracy.In theseapplications,canbeusedmulti-pointcalibrationmethodtogetthebestresults. In multi-point calibration method, not

28、only considered the error of offset and sensitivity,butalsotakesintoaccountmostofthelinearerrorcurveshowninpurple. Themathematicalmodelusedhere,witheachcalibrationinterval(betweenthetwo referencepoints)exactlythesameasatwo-tiercalibration.Three-point calibrationAsmentionedearlier,thelinearformofacon

29、sistenterrorandtheerrorcurvein linewiththequadraticequationofthecurve,withapredictablesizeandshape.Did notusetheamplifierforthesensor,especiallybecauseofthenonlinearsensoris basedonthenatureofmechanicalreasons(thisiscausedbythepressureofsilicon thin-film).Lineardescriptionoftheerrorcharacteristicsofatypicalexamplecanbe calculatedtheaveragelinearerrorto