101
Arm and Gripper Overview
Preparation:•Cleartheworkstation.•OrganizetheTETRIX®andMINDSTORMS®sets.
•ChargetheTETRIXandNXTbatteries.
Materials: •CompletedRangerBotfromLesson3
•TETRIXEducationBaseSet(739143)•LEGO®MINDSTORMS®EducationNXTBaseSet(W979797)
•Software(ROBOTC®orLabVIEW™forLEGOMINDSTORMS)installedoneachcomputer
Resources:•EngineeringJournalWorksheet•ArmandGripperExtensionOverview
•ArmandGripperExtensionBuildingGuide
•ArmandGripperExtensionProgrammingGuide
•ArmandGripperExtensionReferenceGuide
•ArmandGripperExtensionSampleProgram
•Arm and Gripper Extension – How It Should Workvideo
•ArmandGripperExtension3-DModel
Building Objectives:•LearnhowtowireandattachaTETRIXServoMotor.
•IntegrateaMINDSTORMStouchsensorintoaMINDSTORMSwithTETRIXrobot.
Programming Objectives:•LearnhowtoprogramaTETRIXServoMotorinordertopickupandplaceanobject.
•Usesensorinputstosenseobjectsandnavigatetherobot.
Best Practices:BesuretoreviewtheGeneralBestPracticesGuideintheIntroductionsectionoftheTETRIXGettingStartedGuide.
Building
•UsethesmallblackscrewtosecurethehornontheServoMotor.•Useabronzebushinganytimeanaxleisused.•Useaxlespacerstokeepcomponentsinplaceandcorrectlyaligned.
Programming
•Becarefulwhensettingtheopen/closevaluesfortheservo.Itshouldopenfarenoughtofitaroundanobjectandclosetightlyenoughtosecurelyholdtheobject.
•NotethattheWaitfunctionusesmilliseconds.•Notethatfordebuggingpurposes,theNXTBrickdisplaysthesensorvalueswhenrunningtheprovidedsampleprograms.
•Becausedifferentsensorsmayhavedifferentvaluesforthesameobjects,thethresholdvaluesoftheultrasonicsensorandthelightsensormayneedtobechangedandtested.
•Thresholdvaluesfortheservosmayrequiresomeadjustment,dependingonthealignmentandthepositionoftheservo.
Programming (LabVIEW for LEGO MINDSTORMS)
•Makesurethattheportsusedintheprogramcorrespondwiththeschematiceditor.Formoreinformation,consulttheSchematicEditorGuideontheTETRIXGettingStartedGuideDVD.
•Trytokeepthecodelinearandwellorganized.Thismakesthecodemucheasiertofollowanddebug.
Inthisextension,anarmandgripperwillbeassembledandattachedtotheRangerBot.TheRangerBotwillbeprogrammedtofollowaline,pickupacup,andputthecupinabox.
Estimated Time: 90minutes
TETRIX®GettingStartedGuideExtensions