马铃薯播种机得性能评估外文翻译、外文文献翻译、机械类中英文翻译.docx

马铃薯播种机得性能评估外文翻译、外文文献翻译、机械类中英文翻译马铃薯播种机得性能评估外文翻译、外文文献翻译、机械类中英文翻译AssessmentoftheBehaviourofPotatoesinaCup-beltPlanterH.Buitenwerf;W.B.Hoogmoed;P.Lerink;J.MullerFarmTechnologyGroup,WageningenUniversity,P.OBox.17,6700AAWageningen,TheNetherlands;e-mailofcorrespondingauthor:willem.hoogmoedwur.nlKroneGmbH,H 9),theshapeofthepotatoeswasalsoconsideredinthemodel.Twonullhypotheseswereformulated:(1)theplantingaccuracyisnotrelatedtothespeedofthecup-belt;and(2)theplantingaccuracyisnotrelatedtothedimensions(expressedbyashapefactor)ofthepotatoes.Thehypotheseswere。

ewidthandhtheheightofthepotatoinmm,withhowol.Asareference,alsosphericalgolfballs(withaboutthesamedensityaspotatoes),representingashapefactorSof100wereused.ShapecharacteristicsofthepotatoesusedinthisstudyaregiveninTable1.2.2.Mathematicalmodelofthe processAmathematicalmodelwasbuilttopredictplantingaccuracyandplantingcapacityofthecup-beltplanter.Themodeltookintoconsiderationradiusandspeedoftheroller,thedimensionsandspacingofthecups,theirpositioningwithrespecttotheductwallandtheheightoftheplanterab。

ovethesoilsurface(Fig.2).Itwasassumedthatthepotatoesdidnotmoverelativetothecuporrotateduringtheirdownwardmovement.The?eldspeedandcup-beltspeedcanbesettoachievetheaimedplantspacing.Thefrequencyfpotofpotatoesleavingtheductatthebottomiscalculatedaswher evcisthecup-beltspeedinms-1andxcisthedistanceinmbetweenthecupsonthebelt.Theangularspeedoftherollerorinrads-1withradiusrrinmiscalculatedasThisgapxreleaseinmisreachedatacertainangleareleaseinradofacuppassingtheroller.Thisreleaseanglearelease (Fig.2)iscalculatedaswhere:rcisthesuminmoftheradiusoftheroller,thethicknessofthebeltandthelengthofthecup;andxclearistheclearanceinmbetweenthetipofthecupandthewalloftheduct.Whentheparametersofthepotatoesareknown,theanglerequiredforreleasinga。

potatocanbecalculated.Apartfromitsshapeandsize,thepositionofthepotatoonthebackofthecupisdeterminative.Therefore,themodeldistinguishestwopositions:(a)minimumre-quiredgap,equaltotheheightofapotato;and(b)maximumrequiredgapequaltothelengthofapotato.The timetreleaseinsneededtoformareleaseangleaoiscalculatedasCalculatingtreleasefordifferentpotatoesandpossiblepositionsonthecupyieldsthedeviationfromtheaveragetimeintervalbetweenconsecutivepotatoes.Combinedwiththedurationofthefreefallandthe?eldspeedofthep。

lanter,thisgivestheplantingaccuracy.Whenthepotatoisreleased,itfallstowardsthesoilsurface.Aseachpotatoisreleasedonauniqueangularposition,italsohasauniqueheightabovethesoilsurfaceatthatmoment(Fig.2).Asmallpotatowillbereleasedearlierandthusatahigherp ointthanalargeone.Themodelcalculatesthevelocityofthepotatojustbeforeithitsthesoilsurfaceuendinms-1.Theinitialverticalvelocityofthepotatov0inms-1isassumedtoequaltheverticalcomponentofthetrackspeedofthetipofthecup:whereyrinmisthedistancebetweenth。

ecentreoftheroller(lineAinFig.2)andthesoilsurface.Thetimeoffreefalltfallinsiscalculatedwithwheregisthegravitationalacceleration(9.8ms2)andthe?nalvelocityvendiscalculatedaswithv0inms-1beingtheverticaldownwardspeedofthepotatoatthemomentofrelease.The timeforthepotatotomovefromLineAtothereleasepointtreleasehastobeaddedtotfall.Themodelcalculatesthetimeintervalbetweentwoconsecutivepotatoesthatmaybepositionedindifferentwaysonthecups.Thelargestdeviationsinintervalswilloccurwhenapotatopositionedlength。

wiseisfollowedbyonepositionedheightwise,andviceversa.2.3.ThelaboratoryarrangementAstandardplanterunit(MiedemaHassiaSL4(6)wasmodi?edbyreplacingpartofthebottomendofthesheetmetalductwithsimilarlyshapedtransparentacrylicmaterial(Fig.3).Thecup-beltwasdrivenv iatheroller(8inFig.1),byavariablespeedelectricmotor.Thespeedwasmeasuredwithaninfraredrevolutionmeter.Onlyonerowofcupswasobservedinthisarrangement.Ahigh-speedvideocamera(SpeedCamPro,Wein-bergerAG,Dietikon,Switzerland)wasusedtovisualizethebehaviourofthe。

potatoesinthetransparentductandtomeasurethetimeintervalbetweenconsecutivepotatoes.Asheetwithacoordinatesystemwasplacedbehindtheopeningoftheduct,theXaxisrepresentingthegroundlevel.Timewasregisteredwhenthemidpointofapotatopassedthegroundline.Standarddevi ationofthetimeintervalbetweenconsecutivepotatoeswasusedasmeasureforplantspacingaccuracy.Forthemeasurementsthecamerasystemwassettoarecordingrateof1000framespersecond.Withanaveragefreefallvelocityof2.5ms-1,thepotatomovesapprox.2.5mmbetweentwoframes,suf?ci。

entlysmalltoallowanaccurateplacementregistration.Thefeedingratesforthetestoftheeffectofthespeedofthebeltweresetat300,400and500potatoesmin-1(fpot=5,6.7and8.3s-1)correspondingtobeltspeedsof0.33,0.45and0.56ms-1.Thesespeedswouldbetypicalforbeltswith3, 2and1rowsofcups,respectively.A?xedfeedingrateof400potatoesmin-1(cup-beltspeedof0.45ms-1)wasusedtoassesstheeffectofthepotatoshape.Fortheassessmentofanormaldistributionofthetimeintervals,30potatoesin?verepetitionswereused.Intheothertests,20potatoesi。

nthreerepetitionswereused.2.4.StatisticalanalysisThehypothesesweretestedusingthe。