P14007: Wheelchair Assit

P14007: Wheelchair AssistFinal PresentationChe-An Lee Industrial and System EngineerDan Schuster Mechanical EngineerPhil Medalie Mechanical EngineerTom Elliot Electrical EngineerSponsor: Multidisciplinary Senior Design Program

AgendaProject DescriptionDesign ConceptSystem ArchitectureProject StatusTest ResultsConclusionchean2Project DescriptionDesign a low cost device that maintain the characteristic of a manual wheelchair and prevent the wheelchair to roll backKey Customer Needs and Engineering Metrics:

cheean3Design Concept

PawlBrake DiskBearing BlockRatchetCaliperphil4

Design Concept Cont.PawlBrake DiskBearing BlockRatchetCaliperphil5Design Concept Cont.

Tom6Design Concept Cont.Left Generator Input Banana ClipsRight Generator Input Banana ClipsBoth Bridge RectifiersCircuit Breaker SwitchZener DiodeBuck-Boost Regulator 5 VoltsUSB out with USB Circuitry.

Tom7System Architecture

chean8Project Status

Design meets all customer needs except:Weight (0.5 lbs over)Charging system is not on the chairUnable to test:Maximum weight at 10 degree inclineCompleted BOM for working prototypeCompleted all mechanical systems under budgetchean9Test Results

dan10ConclusionCurrent Results:Demonstrated a cost effective solution for rolling backwardsDesign maintains important characteristics of a manual wheelchairGenerator system succeeded in charging a batteryFuture Work:Weight reductionUniversally adaptable to most manual wheelchairsIncorporate movement assist into designMore efficient generator system to charge batteries at lower speeds

dan11Comments/Questions?Sheet1Project:14007Revision #:rqmt. #ImportanceSourceFunctionEngr. Requirement (metric)Unit of MeasureMarginal ValueTarget ValueIdeal ValueComments/StatusTest (how are you going to verify satisfaction)S19C1System OperationMaximum weight at incline of 10 degrees where the wheel chair does not roll backwardslbf260300400Assuming the wheelchair doesn't tip over during testPlace wheelchair on 10 degree incline and incrementally increase weight until chair rolls backwardsS23C12System OperationUser/Assistor disengageable Hill Holderseconds521Can be disengageable by user/assister; should work like an on/off switchTime study for how long the device takes to disengageS33C12System OperationUser/Assistor engageable Hill Holderseconds10.50.1Time study for how long the device takes to engageS49C1System OperationMaximum incline angle, before tipping over backwards with user weight of 300lbfDegreesSame as originalBetter than originalPlace wheelchair on surface that will slowly rotate until the chair tips overS59C2System OperationMaximum downhill speed at decline of 10 degrees at 300lbf user weightmph43User VariedAdd a weight of 300lbs to the chair and determine speed using time and distanceS63C12System OperationUser/Assistor disengagable Gradual Gradeseconds521Can be disengageable by user/assister; should work like an on/off switchTime study for how long the device takes to disengageS73C12System OperationUser/Assistor engagable Gradual Gradeseconds10.50.1Time study for how long the device takes to engageS83C12System OperationUser/Assistor Disengagable movement assistseconds521Can be disengageable by user/assister; should work like an on/off switchTime study for how long the device takes to disengageS93C12System OperationUser/Assistor engagable movement assistseconds10.50.1Time study for how long the device takes to engageS103C5System PortabilityTotal System Weightlbf20105WeighS119C7System OperationCost of Wheel Chair Assist System$1000500200Production level costsS123C6System PortabilityWheel chair width when foldedin2618Unchanged original widthBased on the customer's wheelchairFold chair and measure widthS133C9System OperationWheel chair turning radiusft210Spin chair and measure the turning radiusS143C4System PortabilityTime to remove wheel chair assist systemminutes15105Measure the amount of time it takes for the user to completely detatch the systemS153C10System OperationLength of Wheel Chair + Movement Systemin4840Unchanged from originalBased on the customer's wheelchairMeasure the length of the chairS163C10System OperationWidth of Wheel Chair + Movement Systemin3529Unchanged from originalBased on the customer's wheelchairMeasure the width of the chairS179C8System OperationCritical mechanical components have X number of use cyclescycles400050006000This will be tested computationally and/or with a finite element analysisAnalytical and FEA packageS183C13System OperationCurrent output to battery at 5V when moving 1 mphAmps0.1250.251Tested by moving the chair at 1mph and mesuring the current going into battery.S193C13System OperationCurrent output to battery at 5V when moving 4 mphAmps0.514Tested by moving the chair at 4 mph and mesuring the current going into battery.S203C5System PortabilityRatchet System Weightlbf631.5WeighS213C5System PortabilityBrake System Weightlbf421WeighS223C5System PortabilityCharging System Weightlbf1052.5WeighS239C7System OperationRachet System Cost$30015060Production level costsS249C7System OperationBrake System Cost$20010040Production level costsS259C7System OperationCharging System Cost$500250100Production level costsS269C1System OperationHill Holder Roll back distancein210.5MeasureS273C4System OperationWear Item Replacement Timeminutes30155Time studyS283C2System OperationUser Input Braking Forcelbf20105Fish hook scaleS293C13System OperationGenerator's Max Load Torquelbf-ft410.5Use weights extened at .5ft and Drop them with 5 ohms Resistive loads on the generator.Rqmt. #: enables cross-referencing (traceability) and allows mapping to lower level requirements within separate documentsSource: Customer requirement #, regulatory standard (eg. EN 60601), and/or "implied" (must exist but doesn't have an associated customer rqmt), constraintDescription: quantitative, measureable, testable details*This table can be expanded to document test results

Sheet2Customer RequirementEngr. Requirement (metric)"Hill Holder"Maximum weight at incline of 10 degrees where the wheel chair does not roll backwards"Gradual grade" (Brake System)User/Assistor disengageable Hill HolderLow weightUser/Assistor engageable Hill HolderCollapsibleUser/Assistor disengagable Gradual GradeLow costUser/Assistor engagable Gradual GradeSmall turning radiusUser/Assistor Disengagable movement assistSize, overallTotal System WeightLarge user weight rangeCost of Wheel Chair Assist SystemDisengagable devicesWheel chair width when foldedAbility to provide electricity for user to charge personal electronicsWheel chair turning radius

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Sheet1Test #Specification TestedTarget ValueResult1Max weight at 10 degree incline400 lbf260 lbf2Time to disengage2 sec3.56 sec3Time to engage0.5 sec0 sec4Max. incline angle6 13 5Max. downhill speed3 mphUser Varied6Time to disengage2 sec0 sec7Time to engage0.5 sec0 sec8Turning radius1 ft.0 ft9Time to remove system10 min6 min10Current output at 1mph0.25 amps0 amps11Current output at 4mph1 amps1.04 amps12Rollback distance1 inch0.25 inches13Time (replacement)15 min9 min14Input force10 lbf1.32 lbf15System Weight20 lb20.5 lb16Torque with 5 ohms resistive load1 lbf2.72 lbf17Total System Cost (Purchased Parts)$500$43818Wheelchair Width when folded18 inches17 inches19Wheelchair Width29 inches25.5 inches20Wheelchair Length40 inches38.5 inches

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