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The RSS LabBot BaseMIT Robotics Science and SystemsSpring 2005http://courses.csail.mit.edu/6.141/Prof. John Leonard jleonard@mit.edu Dr. Una-May O'Reilly unamay@csail.mit.edu Prof. Nick Roy nickroy@csail.mit.edu Prof. Daniela Rus rus@csail.mit.edu Prof. Seth Teller teller@csail.mit.edu Aisha Walcott aisha@mit.edu Aaron Edsinger-Gonzales edsinger@csail.mit.edu James McLurkin jamesm@csail.mit.edu OverviewThis document describes the base for the LabBot designed for MIT course 6.141, RoboticsSystems & Science. (http://courses.csail.mit.edu/6.141/). The base includes the mechanicalchassis and motors. A main computer, sensors, motor controller and batteries will need to beadded to this design to build a complete robot. We used the OrcBoard as a motor controller,sensor interface, and power supply for the single board computer. The pentium-based singleboard computer ran Linux and Java. The system diagram on the next page illustrates how thesecomponents were connected.
The chassis was designed to provide undergraduates with a kit simple enough to build in atwo-hour lab session. It is large enough to hold a commercial single board computer and amedium lead-acid battery. The extruded aluminum structural components from 80/20 make iteasy to attach new components, and can be easily re-assembled into different configurations. Themotors have good encoders, and are powerful enough to drive a robot many times this size. Thespherical wheel castors eliminate the odometry errors caused when normal castors must rotatebefore they roll, but have little ground clearance and limit the robot to smooth surfaces.We designed three custom mechanical parts. This machining of these parts was not difficult,but beyond the scope of our course, and these parts were sent to a commercial shop forfabrication. All parts can be disassembled and reused for many terms.LabBot Electrical/Computer System Diagram
LabBot Chassis Exploded Diagram
Motor Wheel Assembly Exploded Diagram
MIT RSS LabBotBill of MaterialsOff-the Shelf Parts:Qty onRobot1Manufacturer-ManufacturerPart #-DistributerHome DepotDistributerPart #-Price5Price/Robot5380/201010Air S025Air IncorporatedAir IncorporatedAir IncorporatedAir IncorporatedAir IncorporatedAir IncorporatedMcMaster-CarrServo Components & Systems, 55.3560.38?1865.466.37.721.41219?37211 5 x 7/8" hi-tech performa wheel2Colsen15441Oxford 5-25?15?150?-?#1DescriptionPeg Board base215" 80/20 Frame3456131410813" 80/20 Frame Rail5" 80/20 Roll Bar RailL brackettriangle brackettriangular plate1/4-20 x 1/2" BHSCS & Econ T-Nutwheel axle adaptor boltsmotor w/ 62.5:1 gear boxspherical wheel castorwheel bolt - 18-8 SS Flat Head Socketmotor mounting boltmotor standoffs - 1/4" stand-offs, 1/4"ball bearingscastor mounting nutsbatteryzip tiesrobot motor controller (ORC Board)single board computer (SBC)23 battery charger1Spherical Wheel50PTimken1418 thin profile--Outwater Plastics McMaster-CarrAll ElectronicsMcMaster-CarrEd OlsenGlobeTekM50P-BK92210A619?GC-125-total parts cost 649.71Custom PartsQty onRobotManufacturerManufacturerPart #DistributerDistributerPart #motor mounting bracket2----wheel axle adaptor - shaftwheel axle adaptor - clamp22----#Description79Motor mount standoff4---LabBotBOM.xls-PricePrice/Robot?Page 1 of 2
MIT RSS LabBotBill of MaterialsOff-the Shelf Parts:#1DescriptionPeg Board base215" 80/20 Frame3456131410813" 80/20 Frame Rail5" 80/20 Roll Bar RailL brackettriangle brackettriangular plate1/4-20 x 1/2" BHSCS & Econ T-Nutwheel axle adaptor boltsmotor w/ 62.5:1 gear boxQty onRobot CAD FilePegboardBase.SLDPRT13222425042Distributer Web nMotor.SLDPRTwww.clickautomation.com Denniswww.colsoncaster.com/casFred TrianglePlate.SLDPRT223 battery charger 0.21 per inch, 1.85/cut97" lengths stock1010.SLDPRT11 5 x 7/8" hi-tech performa wheelspherical wheel castorwheel bolt - 18-8 SS Flat Head Socketmotor mounting boltmotor standoffs - 1/4" stand-offs, 1/4"ball bearingscastor mounting nutsbatteryzip tiesrobot motor controller (ORC Board)single board computer (SBC)Notes603-329-8151 x 13877-232-0307800-631-8375TIMKEN 1418 enPadham201-784-1000 x250,spadham@globtek.coCustom Parts#Description7motor mounting bracket9wheel axle adaptor - shaftwheel axle adaptor - clampMotor mount standoffQty onRobot CAD File100 007 00 WheelHanger.SLDPRT,100 007 00 WheelHanger.pdf2100 002 00 MotorShaft.SLDPRT,100 002 00 MotorShaft.pdf2100 003 00 MotorClamp.SLDPRT2100 004 00 MotorStandoff.SLDPRT,100004 00 MotorStandoff.pdf4LabBotBOM.xlsPage 2 of 2
DIMENSIONS ARE IN INCHESTOLERANCES:FRACTIONALANGULAR: MACHBENDTWO PLACE DECIMALTHREE PLACE DECIMALPROPRIETARY AND CONFIDENTIALTHE INFORMATION CONTAINED IN THISDRAWING IS THE SOLE PROPERTY OF INSERT COMPANY NAME HERE . ANYREPRODUCTION IN PART OR AS A WHOLEWITHOUT THE WRITTEN PERMISSION OF INSERT COMPANY NAME HERE ISPROHIBITED.MATERIALFINISHNEXT ASSYUSED ON---NAMEDATE COMPANY NAME DRAWNCHECKEDENG APPR.MFG APPR.Q.A.COMMENTS:SIZEDWG. NO.REV.AAPPLICATIONDO NOT SCALE DRAWINGSCALE:1:2WEIGHT:SHEET 1 OF 1
.607#6 Counterbore Socket Cap screw (x2)1.000.563.375B.750.138.250 THRUCut from same stock0.025" slitting sawR.4375.1886-32 Tapped x2.563R.125Bearing shaftSlot Depth.800.8750.87451.7604xSlots with0.025" slitting saw1.000.025Slitting Saw x4.40082Degree Counterbore.03.660.098MIT CSAIL.1003/8-16 Bottom TappedDETAIL BSCALE 2 : 1UNLESS OTHERWISE SPECIFIED:DIMENSIONS ARE IN INCHESTOLERANCES:TWO PLACE DECIMAL.01THREE PLACE DECIMAL .003DrawingProjectDateMaterialFinishQuantity100 002 00 MotorShaftRSS Cart1/11/20056061-T6 AluminumAnodize Black30 of each partAaron Edsinger617.253.7471
.375.49310-32 Thru HoleMIT CSAILUNLESS OTHERWISE SPECIFIED:DIMENSIONS ARE IN INCHESTOLERANCES:TWO PLACE DECIMAL.01THREE PLACE DECIMAL .003DrawingProjectDateMaterialFinishQuantity100 004 00 MotorStandoffRSS Cart12/15/20046061-T6 AluminumAnodize Black60Aaron Edsinger617.253.7471
12 spherical wheel castor 2 Spherical Wheel 50P Outwater Plastics Industries M50P-BK 12.5 25 15 wheel bolt - 18-8 SS Flat Head Socket 2 - - McMaster-Carr 92210A619 ? ? 16 motor mounting bolt 4 - - McMaster-Carr ? ? ? 17 motor standoffs - 1/4" stand-offs, 1/4" 2 - - McMaster-Carr ? ? ? 24 ball bearings 2 Timken 1418 thin profile ?
