I N T R O D U C T I O NT OI N D U S T R I A LR O B O T S I n d u s t r i a l R o b o t st y p e s
Contents Initialconsiderations 3 RoboticTypes Cartesian 3 Cylindrical 4 SphericalorPolar 4 Scara 5 DeltaorParalel 5 Articulated 6 Articulated Types 4-axis 7 5-axis. 7 Articulated Types 6-axis 7 6-axisSphericalWrist. 8 6-axisOfsetWrist. 8 6-axisOfsetJoint. 8 6-axisThreeRol,HoloworLemmaWristRobots 9 7-axis 9 Externalaxes&manipulators RotaryTables 10 Gantries,RailsorLinearAxes 11 HybridRobots Combiningthebestofeach 12
itialco sideratio s artesia 3 Beforewepresentthediferenttypesofrobotswemust firstintroducetheconceptof degreeoffreedom which isalsoknownasanaxis.anaxisisapointofrotational (Revolute)orthelineoflinearmovement(Prismatic).For example,atypicalcncmilingmachinehas3prismatic axesandindustrialrobotstypicalyhave6revoluteaxesof rotation. Robotictypes Asimplerdefinitionofrobotictypescanbenarowed downtofivetypes:cartesian,cylindrical,scara,delta andarticulated.eachindustrialrobottypehasspecific elementsthatmakethem best-suitedfordiferent applications.themaindiferentiatorsamongthem are theirspeed,size,andworkspace. Cartesianrobotsarealsocaledrectilinearorgantryrobots.Theyarethemostcommontype ofrobotusedinindustry.cartesianrobotshavethreeprismaticjointsthatusethecartesian coordinatesystem (X,Y,andZ).They mayhaveanatachedwristtoalowforadditional rotationalmovement.thethreeprismaticjointsdeliveralinearmotionalongtheaxisand theworkspaceisintheform ofabox. Plantoperatorsoftendefaulttothistypebecausetheyareeasytouseandprogram.The linearmovementsofthecartesianelementsgivetherobotacube-shapedworkspacethat fitsbestwithpick-and-placeapplicationsandcanrangefrom 100milimeterstotensof meters.theserobotsarealsoapopularchoicebecausetheyarehighlycustomizable. Customerscandeterminethestrokelengths,speed,andprecisionoftherobotsbecause mostofthepartsariveseparatelyandareassembledbythemachinebuilders.overal, plantoperatorschoosethisrobotdesignmostoftenfortheflexibilityintheirconfiguration thatalowsthem tomeetspecificapplicationneeds.
yli drical Sphericalor olar 4 CylindricalrobotsareverysimpleandlikeCartesianintheiraxisofmotion. MostCylindricalrobotsaremadeoftwomovingelements:rotaryandlinear actuators.becausetheyhaveacylindricalworkenvelope,machinedesigners mightselectthem fortheireconomyofspace. Therobotcanbeplacedinthemiddleofaworkspaceand,becauseofits rotationelement,itcanworkanywherearoundit.simpleapplicationswhere materialsarepickedup,rotatedandthenplacedworkbestforcylindrical robots.instalationandusearenotcomplex,andtheycomeascomplete solutionswithminimalassembly. Sphericalrobots,alsoknownaspolarrobots,arelikecylindricalrobots,but insteadofhavingonerotaryjointandtwolinearjoints,theyhavetworotary jointsandonelinearjoint.theserobotscanbeusedinsomeofthemost basicroboticsuchaspainting,welding,andassembly. Youwon tfindmanyofthistypeofrobotonthemarketorinfactories today.however,thesphericalrobot,aspicturedabove,istheonethat startedital.withoutsphericalrobotictechnology,wewouldhavenever hadtheunimate,thefirstindustrialrobotproducedinthe1960s. ThisrobotalowedUnimateandothercompaniestodevelopadvanced robottechnologiessuchastheubiquitous6-axiselectromechanicaldriven robots.thoughitonlyhad5-axis,theunimaterobotssignificantly increasedthepaceofproductionformanufacturerstotakenotice.the industrialrobotrevolutionstartedwiththistypeofrobotandtherobot industryandmanufacturersneverlookedback.
Scara eltaor aralel 5 SCARArobotsoferamorecompletesolutionthantheCartesianor Cylindrical.Itfeaturestwoparaleljointsthatprovidecomplianceinone selectedplane.theyareal-in-onerobots,meaningascararobotis equippedwithx,y,zandrotarymotion(4-axis)inonepackagethatcomes ready-to-go,apartfrom theend-of-arm tooling. TheworkenvelopeislikeCylindricalrobots,butithasmoredegreesof motioninaradiusorarch-shapedspace.applicationsarealsolike CylindricalandCartesianrobots,butSCARArobotscanmovequickerthan theothertwo.theyareseenofteninbio-medicalapplicationsduetotheir smalworkarea.becausescarashavetheeasiestintegrationtheywould appeartobethebestsolutionformostapplications,butcartesiansare morecommonbecauseoftheirlevelofcustomization. Deltarobotsarethefastestandoftenmostexpensive.Thesespider-like robotsarebuiltfrom jointedparalelogramsconnectedtoacommonbase. Theyhaveaunique,truncatedsphereworkenvelopandtheirmainadvantage istheirspeedandprecisionwithwhichtheyoperate. Deltarobotsarebestforfastpick-and-placeorproducttransferapplications likemovingsmalpartsfrom aconveyorbeltandplacingthem inboxesor ontoanotherconveyorbelt. Theyalsocomeascompletesolutionsformachinedesignersbutaremore complicatedinusethanthe6-axisorscararobots.thisrobotconfiguration iscapableofdelicate,precisemovementsotheyareheavilyusedinthefood, pharmaceutical,andelectronicindustries.
Articulated 6 Thisrobotdesignfeaturesrotaryjointsandcanrangefrom simpletwo jointstructuresto10ormorerevolutejoints.thearm isconnectedto thebasewithatwistingjoint.thelinksinthearm areconnectedby rotaryjoints.eachjointiscaledanaxisandprovidesanadditional degreeoffreedom,orrangeofmotion.industrialrobotscommonly havefourorsixelectromechanicalydrivenaxes. Themostversatile6-axisarticulatedrobotsoperatelikeahumanarm. Theycantakeanobjectfrom atable-topandplaceitintoacupboard, somethingtheotherrobottypescannotdoeasily. 6-axisrobotscanmovequickly,comeincompletesolutionsbuttheir programmingismorecomplicated,tediousandcostlyifyouare manualyprogrammingtherobot(teaching).thislastfactorhas previouslylimitedtheeconomicaluseofrobotstolargeproduction runs. Articulatedrobotscanbeutilizedforanincrediblenumberof manufacturingprocessesandcanbeinstaledinanunlimitednumber ofconfigurationsusingexternalmanipulators(axes)thatweare requiredtodiscussthem inaseparatelesson.theserobottypesrange insizefrom theverysmaltohugebehemothsthatcanliftover 1000kg.
Articulated Types Articulated Types-Subtypes 7 -axis -axis 6-axis 4-axisarticulatedrobotsareprimarilyusedfor thetransferofmaterials(pick&place).notice thelinkbetweenfirstjointandthej3arm.this keepthehandlingdevicealwaysparalelwiththe base(floor)plate. Theoddsofanyofyouactualyseeinga5-axis articulatedrobotwilhigherthanwinningthe Lotery.Stäubliintroduced5-axismodelsoftheir robotintendedasasupplementorreplacementof expensive5-axiscncmachines.theycreatedthis modelbyblockingthej6andreplacingitwitha machiningspindle. Theideawaseconomicalyvalidifyouwere cutingaluminum orcomposites,butnotforsteel. Stäubli,whohasthereputationforthemost accuraterobots,discontinuedthemarketingand productionofthismodel.theyquicklydiscovered thatthedemandwasnotthere,evenwiththe beterprecisionandrigidity,itwasnotenough. Theproductionmangerspreferdtheversatilityof 6-axisroubotwithaspindlemountedontheJ6. Therearesub-grouptypesof6-axisarticulated robotswithdiferingjointmethodsdesignfor specificprocessesormarkets.
Articulated Types-Subtypes 8 6-axisSphericalWrist 6-axis setwrist 6-axis set oi t Themostpopularandversatileindustrialrobot usedinmanufacturingisthe6-axisarticulated sphericaljointrobot. Anofsetwristand/orofsetjointrobothasthe centerlineofthewristofsetfrom thecenterlineof theadjacentaxis.theofsetwristdesignis typicalyusedforweldingsinceitalowsthe placementofathrough-arm design. Ifyoulookcloselyattheweldingtorchinthe aboveexampleyouwilnoticethatthewelding torchpowerandwirefeedcablesfeedthroughthe centerofthefinalaxisandthroughtheupperarm. Athrough-arm designresultsinaslimmer manipulatorwithoutexteriorcablesorconduitsto impedemovementorsnaginhardtoreachor crcrowdedareas. Thistypeof6-axisarticulatedrobothaseachaxis ofsetfrom theadjacentaxis.thesmalerdrive motorsareintheinteriorofthearm/joint.theofset jointrobotsarewidelyusedinmachineloading tasksduetheirlowercosts,easeofteachingandthe integratedtorquecontrolsensoroneachaxis.this configurationwilstoptherobotmovementifit cocolideswithanobjectormoreimportantly,a person. Thetorquesensorsalowtheusertoeasily manipulatetherobotbypushing/pulingthej6joint manualyinspace.onceyouhavethepositionthe robotyoucanrecordthepositiononthecontrol. Forthisreason,theyareoftencaledcolaborative robots.
Articulated Types-Subtypes 9 6-axisThreeRol,Holow orlemmawristrobots 7-axis Thesetypesofrobotaretypicalyfoundinpaintsprayingfacilities wheretherobotmustbesealedtightlyagainstcontaminationorto preventexplosions. Somerobotmanufacturersaddanadditionaljointbetweenthe2ndand3rdaxis. Theredundant7-Axisdesignprovidesincreasedfreedom ofmotionandhelps achieveoptimum robotpostureindificultconfigurations,especialyweldingin tightplaces.
Externalaxes&manipulators 10 RotaryTables A6-axisrobotcanbeassembledwithasinglerotarytableora2-axis combinationtableaspictured.arotarytablealowstheproduction team torotatethepartwhilekeepinganoptimalrobot configuration. Externalrotarytablesaretypicalyusedinroboticweldingsinceit alowstheusertopositionthepartwheretherobotandwelding torchareintheiroptimalpositions.agoodexampleofthisis keepingthetorchpositionverticalwhilethetablemovesthepart relativetotheverticalweldingtorchwithminimalrobotmovement. Rotarytablescomeinmanyforms,configurationandsizes.Theycanbe1-axis, 2-axis,vertical,horizontalorevenmountedonasingleaxishorizontalpositioner. Themotionoftherotarytablescanbeindexed(stationarywhilewelding)or synchronous(rotatingwhilethewelding)iftheyhavethecorectmotorsandthe controlcapability.forlargeobjectweldingtherearerobust 2-axisrotarytables mountedonarm thatbepositionedverticaly. Theprogrammingofrotaries,ifthepartisheldinoneposition(indexing),isnot verydificultandcanbedonebymanualprogramming(teaching)therobot.ifthe tablemustmoveinasynchronousmovementwiththetorchitisextremelydificult orimpossibletomanualyprogram economicaly.thistypeofproductionrequires averypowerfulof-lineprogrammingsystem.
Externalaxes&manipulators 11 Gantries,RailsorLinearAxes 6-axisrobotscanbeatachedtolinearaxisrailstoextendthe robot sworkspaceenvelop.arobotmountedonasinglelinearaxis providestheadvantageofworkingonlongobjectsorworkspaces whilekeepingtherobotinanoptimalconfiguration.therailscan rangefrom 2m to30m ormore. Robotsmountedonoverheadrailscaneasilydomachineloading withoutwastingvaluableworkspace.noticeintheabovephotohow thej1jointhasanextendedarm tofacilitatethemachineloading. Afewlargepartweldingshopswilevencombineasinglehorizontalaxisora 2-axisrotarytablewitha3-axisgantry.Thiscombinationgivestheproduction team thepossibilitytocompleteawiderangeofcomplexparts. The2-axisrotary/3axisgantryconfigurationabsolutelyrequiresapowerful of-lineprogrammingsystem tobeoperatedeficientlyandprofitably. Productionmanagersworkingonlargeobjectscaninstalarobot ontoa2or3axisgantryconfiguration.thisalowstheproductionof largepartswiththerobotbeingabletoreachintoextremely variablepositions.
HybridRobots 12 Combiningthebestofeach Robotscomeinmanyshapes,sizesandutility.Hopefuly,youcanunderstandwhy the6-axismedium payloadrobotsaretypicalytheperfectchoiceforthe versatilehandlingoflargeandheavierworkpieces.theyarethepopularchoice formachinetending,welding,grinding,polishing,deburing, laser/plasm/water-jetcuting,adhesivedepositionandlowaccuracymachining (+-0.2mm)applications,etc. Robotsareusedinawiderangeofindustrialapplicationsthatprovideprocess solutionsformaterialhandling,materialjoining,paintdispensingandspot welding,justtonameafew.roboticsystemsareseeneverywhereinindustry includingthefoodandbeverage,consumergoods,automotive,airandspace, plastics,wood,andpharmaceuticalindustries. Kuka-Chinahasdevelopedaninterestinghybridrobotthatcombines theversatilityofarobotwristandtheaccuracyandlargeworkspace ofagantrycartesianrobot. TheyreplacedtheJ1,J2andJ3rotaryjoinswithaprecisionlinear axisgantryandcombinedwitharobot,versatilej4,j5andj6wrist jointsontheendofthez-linearaxis. contact@robotmasteracademy.com