OverviewOverviewBackgroundBackground

Fabrication and PartsFabrication and Parts

TestingTesting

Lessons LearnedLessons Learned

Future ImprovementsFuture Improvements

BudgetBudget

ConclusionConclusion

Design Team #10Design Team #10

Michael NoelMichael NoelBrian BrownBrian BrownWilliam MathesonWilliam MathesonGavin MillsGavin Mills

SupervisorSupervisor Dr Alex KalamkarovDr Alex Kalamkarov

PurposePurposeDesign and fabricate a Design and fabricate a device capable of scaling device capable of scaling steel oil storage tankssteel oil storage tanks

Device will have a Device will have a payload of various payload of various sensors – eddy current, sensors – eddy current, visual, ultrasonicvisual, ultrasonic

Will be used to inspect oil Will be used to inspect oil tank walls for defects – tank walls for defects – common corrosion, common corrosion, pitting, weldspitting, welds

Source:http://www.fotosearch.com/Source:http://www.fotosearch.com/EYW192/e008752/EYW192/e008752/

Design RequirementsDesign Requirements

Move at a speed of 10 m/min vertically up tank.Move at a speed of 10 m/min vertically up tank.

Carry a payload of 30 lbs.Carry a payload of 30 lbs.

Must be completely wireless.Must be completely wireless.

Able to scale vertical, steel tanks with diameters Able to scale vertical, steel tanks with diameters greater than 15 m.greater than 15 m.

Mechanical structure expected to withstand 5 Mechanical structure expected to withstand 5 years of daily use. years of daily use.

Project should not exceed a budget of $2500.Project should not exceed a budget of $2500.

Frame and Track SystemFrame and Track System

Main FrameMain FrameBasic box design Basic box design 1/8” thick sheet aluminum1/8” thick sheet aluminumSize was determined by Size was determined by track length and internal track length and internal mechanics and mechanics and electronicselectronicsCut top to proper size and Cut top to proper size and welded sides in placewelded sides in placeHoles were cut for shafts Holes were cut for shafts and mountingsand mountingsSlots cut for front Slots cut for front shaft/tensioning systemshaft/tensioning system

FrameFrameAngle aluminum support Angle aluminum support added to topadded to top

Angle aluminum support Angle aluminum support added to rear shaft added to rear shaft bearing mountsbearing mounts

Tensioning system Tensioning system installedinstalled

Handle added for safety Handle added for safety line when testingline when testing

Finishing Finishing touches/paintingtouches/painting

Tracks and SprocketsTracks and SprocketsPrimo 2” wide Primo 2” wide motorcycle drive beltsmotorcycle drive belts

Strong, rigid, and Strong, rigid, and reinforced (allowed reinforced (allowed holes to be drilled)holes to be drilled)

4 aluminum sprockets 4 aluminum sprockets mated to beltmated to belt

Tracks and SprocketsTracks and SprocketsSprockets were Sprockets were manufactured by manufactured by

in-house technicianin-house technician

Keyways were cut in Keyways were cut in drive sprockets to match drive sprockets to match keyed shaftkeyed shaft

Press fit bearings in front Press fit bearings in front sprockets, free rotating sprockets, free rotating on shafton shaft

MagnetsMagnets

Rare earth magnets called Neodymium (Rare earth magnets called Neodymium (Nd2Fe14) Nd2Fe14) magnetsmagnets were were used used Approximately 30 lb forceApproximately 30 lb forceDimensions: {2 in (length) x ½ in (width) x 1/4 in (thickness)} Dimensions: {2 in (length) x ½ in (width) x 1/4 in (thickness)} 24 magnets/ track24 magnets/ trackScrape easily, covered with nylon tapeScrape easily, covered with nylon tapeBrittle, require strong backingBrittle, require strong backing

Magnet HoldersMagnet HoldersSteel bar stockSteel bar stockSlots for magnets were Slots for magnets were milledmilledChannels-(2 x ½ x 3/16) in Channels-(2 x ½ x 3/16) in Cut to 2” lengthsCut to 2” lengthsBolt holes drilled and Bolt holes drilled and threadedthreadedMagnets extend past Magnets extend past holders’ top edge to ensure holders’ top edge to ensure contact with tankcontact with tank

Holder Attachment and Holder Attachment and TrackTrack GuidesGuides

Holders were attached Holders were attached by two 3/16” X 1” bolts. by two 3/16” X 1” bolts.

Bolts are fitted with two Bolts are fitted with two rubber 9/16” dia – ¼ R rubber 9/16” dia – ¼ R washers washers

Screwed through track Screwed through track and into holderand into holder

Ends were ground offEnds were ground off

Rubber washers act as Rubber washers act as track guidestrack guides

Track AlignmentTrack AlignmentTracks shifting more than anticipatedTracks shifting more than anticipatedRubber washers were wearing from contact Rubber washers were wearing from contact with sprocketwith sprocketGuides were addedGuides were added3/4 “ birch plywood3/4 “ birch plywoodHad to run smoothly between washersHad to run smoothly between washersKept track in lineKept track in line

Drive Drive TrainTrain

Independent drive trainsIndependent drive trains

Planetary MotorsPlanetary Motors

Astro Flight 940PAstro Flight 940P

24 volt, 750 watts24 volt, 750 watts

15:1 all steel planetary gear reduction 15:1 all steel planetary gear reduction

45 rpm/volt * 24 volts = 45 rpm/volt * 24 volts = 1080 rpm unloaded1080 rpm unloaded

Wall climber draws ~25 amps without payloadWall climber draws ~25 amps without payload

Max continuous current 35 amps, 100 amps stallMax continuous current 35 amps, 100 amps stall

Planetary MotorsPlanetary Motors

Worm and Worm GearWorm and Worm Gear Martin hardened steel Martin hardened steel

worm and worm gearworm and worm gear Worm gear has 1.67” Worm gear has 1.67”

pitch diameter, 20 pitch diameter, 20 teethteeth Worm has 1” pitch Worm has 1” pitch diameter, 1 threaddiameter, 1 thread 20:1 gear ratio20:1 gear ratio

Acts as a brake when the Acts as a brake when the motor is not powered, motor is not powered, preventing the robot preventing the robot from rolling down from rolling down

under under gravity gravity

Source: http://www.martinsprocket.com

BearingsBearings Worm shaft Worm shaft supported at each supported at each

end by radial roller end by radial roller bearingsbearings

Thrust bearing Thrust bearing assembly (right) has assembly (right) has

2 thrust bearings to 2 thrust bearings to absorb worm axial absorb worm axial forcesforces

Drive shaft rotates Drive shaft rotates between a pillow between a pillow

block bearing block bearing and a and a flange flange bearingbearing

Speed ControllersSpeed Controllers IFI Victor 883 IFI Victor 883

60 amps continuous60 amps continuous

Vary output voltage Vary output voltage from 10 – 100%from 10 – 100%

Forward and reverse Forward and reverse motionmotion

Active cooling with Active cooling with 24V fan 24V fan

Low voltage dropLow voltage drop

Radio ControllerRadio ControllerAirtronics Avenger 2X Airtronics Avenger 2X

2 channels2 channels

Wireless receiver plugs Wireless receiver plugs into speed controllers into speed controllers

Joystick A controls right Joystick A controls right motor, joystick B motor, joystick B controls left motorcontrols left motor

Source: http://www.airtronics.net

Battery PacksBattery Packs 24 volt nickel metal 24 volt nickel metal hydride battery backshydride battery backs

20 cells * 1.2 volts 20 cells * 1.2 volts per per cellcell

3.5 amp*hour 3.5 amp*hour capacitycapacity

One pack per motorOne pack per motor

Rated capacity falls Rated capacity falls as discharge rate as discharge rate increasesincreases

Source: http://www.uniross.com

TestingTesting

•Testing was done on two structures.

Testing Problems and SolutionsTesting Problems and Solutions    

ProblemProblem Solution (s)Solution (s)

1. Body flex under load1. Body flex under load • Angle-bar installed across topAngle-bar installed across top

2. Flange bearing shift due to 2. Flange bearing shift due to track tensiontrack tension

• Angle-bar support installed against Angle-bar support installed against flange housingflange housing

3. Friction wearing on worm 3. Friction wearing on worm geargear  

• Pillow block mount shortened and Pillow block mount shortened and drive train realigneddrive train realigned• Lithium grease added to worm/worm Lithium grease added to worm/worm gear assemblygear assembly

4. Track misalignment while 4. Track misalignment while turningturning

• Runner added between front and rear Runner added between front and rear cogcog

5. Short battery life5. Short battery life  

• Multiple charges and dischargesMultiple charges and discharges• Drive train lubrication and Drive train lubrication and realignmentrealignment

  

Testing ResultsTesting Results      

CriteriaCriteria DesiredDesired AchievedAchieved

SpeedSpeed 10 m/min upward10 m/min upward 21 m/min upward21 m/min upward

PayloadPayload 30 lbs30 lbs 50 lbs50 lbs

Wireless operationWireless operation yesyes yesyes

Onboard inspection cameraOnboard inspection camera yesyes yesyes

Battery lifeBattery life 15 min15 min 10 min10 min

Turning on vertical surfaceTurning on vertical surface yesyes yesyes

Smallest oil tank diameterSmallest oil tank diameter 15 m15 m 10 m10 m

Robot weightRobot weight 30 lbs30 lbs 52 lbs52 lbs

Lessons LearnedLessons Learned FabricationFabrication

Measure Twice ~ Cut OnceMeasure Twice ~ Cut Once Liaise with technicians Liaise with technicians

regularlyregularly Expect a busy machine shopExpect a busy machine shop Small changes in design can Small changes in design can

decrease fabrication time decrease fabrication time & & costscosts Research suppliers ie. size of Research suppliers ie. size of

stocked parts during the stocked parts during the design phasedesign phase Source: http://www.acclaimimages.com/_gallery/

Lessons LearnedLessons Learned Components/PartsComponents/Parts

Order ASAPOrder ASAP Expect delaysExpect delays Inform seller how to shipInform seller how to ship Plan for:Plan for:

Defective partsDefective parts Wrong partsWrong parts

In stock today ~ Out of stockIn stock today ~ Out of stocktomorrow tomorrow

Ask what comes in the box Ask what comes in the box

Future ImprovementsFuture Improvements

Smaller overall sizeSmaller overall size Reduce weightReduce weight

Additional support for drive shaftAdditional support for drive shaft Limit flexing of shaftLimit flexing of shaft

Sub-frame assemblySub-frame assembly More rigid than current aluminum bodyMore rigid than current aluminum body

Redesign magnet holdersRedesign magnet holders Reduce weight / prevent movement of magnetsReduce weight / prevent movement of magnets

Investigate battery optionsInvestigate battery options Increase operational timeIncrease operational time

Future ImprovementsFuture ImprovementsRedesign track alignment systemRedesign track alignment system

Future Future ImprovementsImprovementsFind guide material with higher abrasion Find guide material with higher abrasion resistanceresistance

BudgetBudgetMajor Expenses

$ 2677.40

Bearings $145.00

Stock Metal $245.00

Gears $160.00

Belts $316.40

Paint $47.00

Batteries $240.00

Motors $882.00

Magnets $179.00

Customs $175.00

Mock Up $200.00Note: Speed controllers were not included ($385)

$2500.00

Special ThanksSpecial Thanks

SupervisorSupervisorDr Alex KalamkarovDr Alex Kalamkarov

DP CoordinatorDP CoordinatorDr Ted HubbardDr Ted Hubbard

Special ThanksSpecial Thanks

Dept TechniciansDept TechniciansAlbert Murphy (Lead)Albert Murphy (Lead)Angus MacphersonAngus Macpherson

Stewart CarrStewart Carr

Mechanical DeptMechanical DeptPeter, Greg, Luke, and LisaPeter, Greg, Luke, and Lisa

Special ThanksSpecial Thanks

Our ClientOur Client

Dr Jason GuDr Jason GuDalhousie Electrical DepartmentDalhousie Electrical Department