会员注册 | 登录 | 微信快捷登录 QQ登录 微博登录 | 帮助中心 人人文库renrendoc.com美如初恋!
站内搜索 百度文库

热门搜索: 直缝焊接机 矿井提升机 循环球式转向器图纸 机器人手爪发展史 管道机器人dwg 动平衡试验台设计

   首页 人人文库网 > 资源分类 > DOC文档下载

外文翻译--移栽水稻幼苗机制和发展.doc

  • 资源星级:
  • 资源大小:41.50KB   全文页数:7页
  • 资源格式: DOC        下载权限:注册会员/VIP会员
您还没有登陆,请先登录。登陆后即可下载此文档。
  合作网站登录: 微信快捷登录 支付宝快捷登录   QQ登录   微博登录
友情提示
2:本站资源不支持迅雷下载,请使用浏览器直接下载(不支持QQ浏览器)
3:本站资源下载后的文档和图纸-无水印,预览文档经过压缩,下载后原文更清晰   

外文翻译--移栽水稻幼苗机制和发展.doc

外文翻译单行蔬菜钵体苗自动移栽机的设计取苗装置设计原文2Developmentofamechanismfortransplantingriceseedlings译文2移栽水稻幼苗机制和发展原文2Transplantingofseedlingsisalaborintensiveoperationinthecultivationofrice.Itisalsoaskilledjobandinvolvesworkingwithastoopingpostureinapuddledfield.Thereexistsaneedtomechanizethisoperation.Forthispurposethedesignofamechanismwascarriedoutfollowingthemethodofanalyticalsynthesis.Aplanarfourbarlinkagewithcouplerextensionwasselectedasthebasicdesign.Thepathgeneratedbythemechanismwasplottedonacomputerscreen.Byvaryingthedimensionsofvariouslinksinthemechanismdifferentpathsofoutputmotionofthecouplerpointwereobtained.Thepotentiallinkdimensionswereidentifiedbasedonthesuitabilityofthepathforpicking,conveyingandplantingofseedlingsaswellasthereturnmotion.Afourrowselfpropelledtransplanterusingtheabovemechanismandanoptimizedplantingfingerwasthendevelopedandtested.Themachinetransplantingsystemwasfoundtobetechnicallyviable.Indiaispredominantlyanagriculturalcountrywithriceasoneofitsmainfoodcrop.Itproducesabout80milliontonsriceannually,whichisabout22oftheworldriceproduction.Culturally,transplantingofyoungseedlingsof20–35daysageinwaterinundatedfieldispreferredoverdirectseeding.Theformerleadstobetteryieldduetobettercropmanagementpracticesthatarepossibleinatransplantedcrop.Theoperationoftransplantingrequireslargeamountofmanpowerabout400manhour/haandthetaskisverylaboriousinvolvingworkinginastoopingpostureandmovinginmuddyfield.Hence,thisisconsideredasanactivitythatneedsmechanization.Mechanizationoftransplantingfacilitatesmechanizationofsubsequentactivitiesalsointheproductionofthecrop.ThemachinesthatarealreadysuccessfulinJapanandKoreacouldnotbeadoptedinIndiabecauseofeconomiccostconstraintsandduetotheprevailingculturalpracticesofthiscountry.Designofplantingmechanismsusedinpoweroperatedtransplanters.Anon.statesthatmostoftheplantingdevicesofpoweroperatedtransplanterscanbeclassifiedascrankandrockermechanismsoffourbarlinkage.Aplantingfinger,whichisapartofthecouplerlinkofthemechanism,separatestheseedlingsfromtheseedlingtrayandplacestheminthesoil.Thecurvetracedbytheplantingfingermayhaveaninfluenceonthestabilityoftheplantedseedlings.Thekinematicanalysisoftheplantingmechanismsisconsideredessentialforanunderstandingofitsoperationanditsfurtherimprovements.DesignofmechanismErdmanandSandorstatemostmechanismtasksrequireasingleinputtobetransferredtoasingleoutput.Therefore,singledegreeoffreedommechanismsaretheformsusedmostfrequently.ShigleystatesthatGrublerscriterionisconcernedwiththenumberoflinksinthemechanismandwiththenumberandkindsofkinematicpairs.Itcanbeusedfordeterminingthedegreeoffreedomofamechanism.ErdmanandSandorstatethatanalysistechniquescanbeusedtoreplacecostlyandtimeconsumingbuildingandtestingofphysicalprototypesinatrialanderrordesignprocess.Analysistechniquesgenerallyformabasicpartofmostsynthesismethods.Nortonstatesthatthefourbarlinkageshouldbeamongthefirstsolutionstomotioncontrolproblemstobeinvestigated.Thefewestpartsthatcandothejobwillusuallygivetheleastexpensiveandmostreliablesolution.NortonstatesthattheGrashofconditioncanbeusedasaverysimplerelationship,whichpredictsthebehaviorofafourbarlinkage,basedonthelinklengths.Zimmermanstatesthatafourbarmechanismisphysicallyimpossibleifoneofthelinkshasalengthgreaterthanthesumoftheotherthree.Hirschhornstatesthatinafourbarlinkagedistincttypesofmechanismscouldbeobtainedbyinversion.Acrankrockermechanismisobtainedbyfixingoneofthetwolinkspairedwiththeshortestlink.PaulsuggestedthatNewton–Raphsonmethodcouldusedbeusedtosolvethenonlinearequationsdevelopedforsolvingthefourbarlinkagepositionproblem.Zimmermanstatesthatonebasicmechanismdesignproblemforwhichthefourbarchaincanprovidesolutionsisthatoffindingapointofthecouplerofafourbarmechanism,whichdescribesapathcloselyapproximatingthedesiredone.Inamechanicaltransplanterthefingerfollowadesiredpathofmotion.Aplanarfourbarlinkagewithallrevolutepairsischosen,asthisisverysimple,amechanismmadeofthatmaybeE.VareedThomas/MechanismandMachineTheory372002395–410397easytomaintainandmaycostlesstomanufacture.Theinputmotionisappliedtothecranksothatthemotioniscontinuousandrotary.Theoutputmotionfollowasuitablepathinordertomeettherequirementsofatransplanterspecifiedbelow.Themechanismshouldhaveonedegreeoffreedomandacouplerpointthatiscapableofmakingaloopmaybeincorporated.Theplantingfingerwillbeattachedatthecouplerpoint.Thedimensionsoffourlinksinthefourbarloop,orientationofthefixedlink,lengthofthecouplerextensionandorientationangleofthecouplerextensionaretobedecidedforthedesign.Sincethesevaluescouldnotbesynthesizeddirectlyitwasdecidedtoexaminevarioustrialvaluesfortheaboveparametersandstudythesuitabilityofthepathgeneratedbysuchmechanismforthepurposeoftransplanting.Theaboveparameterswerechangedsystematicallyusingarbitrarilysetranges.Duringthepresentinvestigationaround0.23millionlinkagedesignswereexamined.Thechoicesoflinkdimensionsweremadefollowingamethodofanalysisandselection.Thelinkdimensionswerevariedasstatedabove.Thepathofmotionofthetransplantingfingerpointwascalculatedanddisplayedonacomputerscreenforeverytrialvalueoflinkdimensions.Initially,linkdimensionswhichmettheoutputmotionrequirementsasstatedinSection2.1wereselected.DetailsaregiveninSection2.4.Inordertostudythelinkagedesignfurtherandtobringoutpathsthatmaybebetter,smallrangesoflinkdimensionsweresetaroundtheaboveselecteddesignvalues.Thepathoffingerpointmotionwasagainexaminedkeepinginmindtherequirementsstatedearlier.Outofseveraldesigns,one,whichwouldlikelygivethebestpath,wasselected.Thus,analysisandselectionformedthemainstrategyinthedesignprocedure.InitiallytheforwardtravelspeedofthetransplantingmachinewasneglectedsincethiswassmallincomparisontothespeedoftheplantingfingerStage1ofdesign.Theangleofthefixed398E.VareedThomas/MechanismandMachineTheory372002395–410linkwasalsoassumedtobezero.AfterarrivingatanapproximatedesignthesevalueswerealsovariedinStage2.Finally,theshapeofthe

注意事项

本文(外文翻译--移栽水稻幼苗机制和发展.doc)为本站会员(英文资料库)主动上传,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。 若此文所含内容侵犯了您的版权或隐私,请立即通知人人文库网(发送邮件至[email protected]或直接QQ联系客服),我们立即给予删除!

温馨提示:如果因为网速或其他原因下载失败请重新下载,重复下载不扣分。

[email protected] 2015-2017 人人文库网网站版权所有
苏ICP备12009002号-5