自动化专业外文文献.docx

自动化专业外文文献.docx

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自动化专业外文文献

DevelopmentofSensorNewTechnology

Sensorisonekindcomponentwhichcantransformthephysicalquantity,chemistryquantityandthebiomassintoelectricalsignal、Theoutputsignalhasthedifferentformslikethevoltage,theelectriccurrent,thefrequency,thepulseandsoon,whichcansatisfythesignaltransmission,processing,recording,anddemonstrationandcontroldemands、Soitistheautomaticdetectionsystemandintheautomaticcontrolindustry、IfautomaticTechnologyisusedwider,thensensorismoreimportant、

Severalkeywordsofthesensor:

1SensorElements

Althoughthereareexception,mostsensorconsistofasensingelementandaconversionorcontrolelement、Forexample,diaphragms,bellows,straintubesandrings,bourdontubes,andcantileversaresensingelementswhichrespondtochangesinpressureorforceandconvertthesephysicalquantitiesintoadisplacement、Thisdisplacementmaythenbeusedtochangeanelectricalparametersuchasvoltage,resistance,capacitance,orinductance、Suchcombinationofmechanicalandelectricalelementsformelectromechanicaltransducingdevicesorsensor、Similarcombinationcanbemadeforotherenergyinputsuchasthermal、Photo,magneticandchemical,givingthermoelectric,photoelectric,electromaanetic,andelectrochemicalsensorrespectively、

2SensorSensitivity

TherelationshipbetweenthemeasuredandthesensoroutputsignalisusuallyobtainedbycalibrationtestsandisreferredtoasthesensorsensitivityK1=output-signalincrement/measuredincrement、Inpractice,thesensorsensitivityisusuallyknown,and,bymeasuringtheoutputsignal,theinputquantityisdeterminedfrominput=output-signalincrement/K1、

3CharacteristicsofanIdealSensor

Thehighsensorshouldexhibitthefollowingcharacteristics、

（a）highfidelity-thesensoroutputwaveformshapebeafaithfulreproductionofthemeasured;thereshouldbeminimumdistortion、

（b）Thereshouldbeminimuminterferencewiththequantitybeingmeasured;thepresenceofthesensorshouldnotalterthemeasuredinanyway、

（c）Size、Thesensormustbecapableofbeingplacedexactlywhereitisneeded、

（d）Thereshouldbealinearrelationshipbetweenthemeasuredandthesensorsignal、

（e）Thesensorshouldhaveminimumsensitivitytoexternaleffects,pressuresensor,forexample,areoftensubjectedtoexternaleffectssuchvibrationandtemperature、

（f）Thenaturalfrequencyofthesensorshouldbewellseparatedfromthefrequencyandharmonicsofthemeasurand、

Sensorscanbedividedintothefollowingcategories:

1ElectricalSensor

Electricalsensorexhibitmanyoftheidealcharacteristics、Inadditiontheyofferhighsensitivityaswellaspromotingthepossibleofremoteindicationormesdurement、

Electricalsensorcanbedividedintotwodistinctgroups:

（a）variable-control-parametertypes,whichinclude:

（i）resistance

（ii）capacitance

（iii）inductance

（iv）mutual-inductancetypes

Thesesensorallrelyonexternalexcitationvoltagefortheiroperation、

（b）self-generatingtypes,whichinclude

（i）electromagnetic

（ii）thermoelectric

（iii）photoemissive

（iv）piezo-electrictypes

Theseallthemselvesproduceanoutputvoltageinresponsetothemeasurandinputandtheireffectsarereversible、Forexample,apiezo-electricsensornormallyproducesanoutputvoltageinresponsetothedeformationofacrystallinematerial;however,ifanalternatingvoltageisappliedacrossthematerial,thesensorexhibitsthereversibleeffectbydeformingorvibratingatthefrequencyofthealternatingvoltage、

2ResistanceSensor

Resistancesensormaybedividedintotwogroups,asfollows:

（i）Thosewhichexperiencealargeresistancechange,measuredbyusingpotential-dividermethods、Potentiometersareinthisgroup、

（ii）Thosewhichexperienceasmallresistancechange,measuredbybridge-circuitmethods、Examplesofthisgroupincludestraingaugesandresistancethermometers、

3CapacitiveSensor

Thecapacitancecanthusmadetovarybychangingeithertherelativepermittivity,theeffectivearea,orthedistanceseparatingtheplates、Thecharacteristiccurvesindicatethatvariationsofareaandrelativepermittivitygivealinearrelationshiponlyoverasmallrangeofspacings、Thusthesensitivityishighforsmallvaluesofd、  Unlikethepotentionmeter,thevariable-distancecapacitivesensorhasaninfiniteresolutionmakingitmostsuitableformeasuringsmallincrementsofdisplacementorquantitieswhichmaybechangedtoproduceadisplacement、

4InductiveSensor

Theinductancecanthusbemadetovarybychangingthereluctanceoftheinductivecircuit、

Measuringtechniquesusedwithcapacitiveandinductivesensor:

（a）A、C、excitedbridgesusingdifferentialcapacitorsinductors、

（b）A、C、potentiometercircuitsfordynamicmeasurements、

（c）D、C、circuitstogiveavoltageproportionaltovelocityforacapacitor、

（d）Frequency-modulationmethods,wherethechangeofCorLvariesthefrequencyofanoscillationcircuit、

Importantfeaturesofcapacitiveandinductivesensorareasfollows:

（i）resolutioninfinite

（ii）accuracy±0、1%offullscaleisquoted

（iii）displacementranges25*10-6mto10-3m

（iv）risetimelessthan50uspossible

Typicalmeasurandsaredisplacement,pressure,vibration,sound,andliquidlevel、

5LinearVariable-differentialTtransformer

6Piezo-electricSensor

7ElectromagneticSensor

8ThermoelectricSensor

9PhotoelectricCells

10MechanicalSensorandSensingElements

Ininformationage,theinformationindustryincludesinformationgathering,transmission,processthreeparts,namelysensortechnology,communication,computertechnology、Becauseofultralargescaleintegratedcircuit’srapiddevelopmentafterhavingbeendevelopedModerncomputertechnologyandcommunication,notonlyrequestssensorprecisionreliability,speedofresponseandgaininformationcontentrequestmoreandmorehighbutalsorequestsitscosttobeinexpensive、Theobvioustraditionalsensoriseliminatedgraduallybecauseofthefunction,thecharacteristic,thevolume,thecostandsoon、Asworlddevelopmanycountriesarespeedinguptothesensornewtechnology’sresearchandthedevelopment,andallhasobtainedtheenormousbreakthrough、Nowthesensornewtechnologydevelopmentmainlyhasfollowingseveralaspects:

Usingthephysicalphenomenon,thechemicalreaction,thebiologicaleffectasthesensorprinciplethereforetheresearcheswhichdiscoveredthenewphenomenonandtheneweffectarethesensortechnologicalimprovingways、itisimportantstudiestodevelopednewsensor’sthefoundation、JapaneseSharpCorporationusesthesuperconductivitytechnologytodevelopsuccessfullythehightemperaturesuperconductivitymagneticsensorandgetthesensortechnologysignificantbreakthrough、Itssensitivityissohighandonlyinferiorinthesuperconductivityquantuminterferencecomponent、Itsmanufacturecraftisfarsimplerthanthesuperconductivityquantuminterferencecomponent、Mayuseinmagnetismimageformationtechnology、Soithasthewidespreadpromotedvalue、

Usingtheimmunebodyandtheantigenmeetsoneanothercompoundwhentheelectrodesurface、Itcancausetheelectrodepotentialchangeandusethisphenomenontobepossibletogeneratetheimmunitysensor、Theimmunitysensormakeswiththiskindofimmunebodymaytosomeorganisminwhetherhasthiskindofantoriginalworkinspection、Likemayinspectsomebodywiththehepatitisvirusimmunebodywhethercontractsthehepatitis,playstoisfast,theaccuraterole、TheUSUCsixthbranchhasdevelopedthiskindofsensor、

Thesensormaterialistheimportantfoundationforsensortechnology,becausethematerialsscienceisprogressiveandthepeoplemaymakeeachkindofnewsensorForexamplemakingthetemperaturesensorwiththehighpolymerthinfilm;Theopticalfibercanmakethepressure,thecurrentcapacity,thetemperature,thedisplacementandsoonthemanykindsofsensors;Makingthepressuretransmitterwiththeceramics、Thehighpolymercanbecometheproportionadsorptionandthereleasehydrogenalongwiththeenvironmentrelativehumiditysize、Thehighpolymerelectricityliesbetweentheconstanttobesmall,thehydrogencanenhancethepolymerthecoefficientofdialecticalloss、Makingthecapacitorthehighpolymerdielectricmedium,determinestheelectriccapacitycapecitythechange,thenobtainstherelativehumidity、Makingtheplasmausingthisprincipletogatherthelegitimatepolystyrenefilmtemperaturesensorbelow,ithasthecharacteristic、

Measuredthewetscopeiswide;Thetemperaturerangeiswide,mayreach-400℃~+1,500℃;Thespeedofresponseisquick,issmallerthan1S;Thesizeissmall,mayuseinthesmallspacemeasuringwet;Thetemperaturecoefficientissmall、

Theceramicelectriccapacitytypepressuretransmitterisonekinddoesnothavetheintermediaryfluidthedrytypepressuretransmitter、Usestheadvancedceramictechnology,theheavyfilmelectronictechnology,itstechnicalperformanceisstable,theyeardriftingquantityissmallerthan0、1%F、S,warmfloatsissmallerthan±0、15%/10K,anti-overloadsstrongly,mayreachthemeasuringrangeseveralhundredtimes、Thesurveyscopemayfrom0to60mpa、GermanE+HCorporationandtheAmericanKahloCorporationproductisattheleadingposition、

Theopticalfiberapplicationissendthematerialsignificantbreakthrough,itsusesinmostearlytheopticalcommunicationtechniques、Intheopticalcommunicationusediscoveredworksasenvironmentalconditionchangeandsoonthetemperature,pres-sure,electricfield,magneticfield,causesthefiberoptictransmissionlightwaveintensity,thephase,thefrequency,changeandsoonthepolarizationcondition,thesurveylightwavequ