Post on 30-Jun-2015
description
Fall 2008Grand Valley State University
Eric DomkeDrew Pretzer
Brandon RoodKarl Hiedemann
Powered Wheelchair Trainer Design ProjectFall Semester - 2008
“The ability to move is the first foundation stone in building personal dignity.”
- D. Linda Bidabe
Fall 2008Grand Valley State University
IntroductionIntroduction
● Project DescriptionProject Description● Customer NeedsCustomer Needs● SpecificationsSpecifications● Design EvolutionDesign Evolution● Demonstration & Evaluation of PrototypeDemonstration & Evaluation of Prototype● RecommendationsRecommendations
Fall 2008Grand Valley State University
Problem DescriptionProblem Description
● Must pass test to get Must pass test to get money from insurance money from insurance companycompany
● Not enough practiceNot enough practice● Powered chairs are Powered chairs are
expensiveexpensive● Goal: Build Goal: Build
"inexpensive" device "inexpensive" device which attaches to which attaches to manual wheelchairs.manual wheelchairs.
Fall 2008Grand Valley State University
Target MarketTarget Market
Fall 2008Grand Valley State University
Customer Needs - InterviewsCustomer Needs - Interviews
● Fit through a standard doorFit through a standard door● Change between different wheelchairs quicklyChange between different wheelchairs quickly● Easily transportable between different buildings.Easily transportable between different buildings.● Good battery life.Good battery life.
Fall 2008Grand Valley State University
Product SpecificationsProduct Specifications
● Switch Users in Under 5 MinutesSwitch Users in Under 5 Minutes● Accommodate Different Sized WheelchairsAccommodate Different Sized Wheelchairs
● Widths of 20-25 inchesWidths of 20-25 inches● Lengths of 32-50 inchesLengths of 32-50 inches● Wheelbase of 16-32 inchesWheelbase of 16-32 inches
● Fit Through a Standard DoorFit Through a Standard Door● Width is under 32 inchesWidth is under 32 inches
● Mimic a Powered WheelchairMimic a Powered Wheelchair
Fall 2008Grand Valley State University
Revision ARevision A
● Motor CalculationsMotor Calculations
● Support Bar CalculationsSupport Bar Calculations● 0.065" Wall Thickness for Steel Tube0.065" Wall Thickness for Steel Tube
● Force to Load CalculationForce to Load Calculation● 170 lbs170 lbs
● Tipping CalculationTipping Calculation● Need to move > 9.33" off centerNeed to move > 9.33" off center
Torque (Driving)
480.98 In-lb 54.31 N-m
Torque (Steering)
209.49 In-lb 23.65 N-m
Fall 2008Grand Valley State University
Revision BRevision B
Front of Trainer
1 2 3
Fall 2008Grand Valley State University
Revision CRevision C● Motor TestingMotor Testing
● Cordless motors possible, but Cordless motors possible, but durability and brake concernsdurability and brake concerns
● Frictional Force ExperimentFrictional Force Experiment● Approx. 300 lbf to get a 4" Approx. 300 lbf to get a 4"
dia. wheel over a 0.75" ledgedia. wheel over a 0.75" ledge
Fall 2008Grand Valley State University
Revision DRevision D● Finite Element AnalysisFinite Element Analysis
● Need multiple gussets to Need multiple gussets to minimize deflectionminimize deflection
● Frame Design AnalysisFrame Design Analysis● Tube frame is stronger and Tube frame is stronger and
more cost effectivemore cost effective
Fall 2008Grand Valley State University
Revision ERevision E● Site Visit to LDC #2Site Visit to LDC #2
● Motors cannot go between Motors cannot go between wheelchair wheels.wheelchair wheels.
● Traction AnalysisTraction Analysis● Issues with traction, Issues with traction,
especially on carpet.especially on carpet.
MotorsBatteries
Fall 2008Grand Valley State University
Final DesignFinal Design
Fall 2008Grand Valley State University
LDC – Final VisitLDC – Final Visit
Fall 2008Grand Valley State University
LoadingLoading
● Improvements: NoneImprovements: None
Goal : "Not Strenuous" Actual : Very Easy PASS
Fall 2008Grand Valley State University
LockingLocking
● Improvements: NoneImprovements: NoneGoal : < 5 minutes Actual : < 1 minutes PASS
Fall 2008Grand Valley State University
ManeuverabilityManeuverability
● Improvements: Tweak the controls algorithms Improvements: Tweak the controls algorithms and deal with traction issues.and deal with traction issues.
Goal : Similar to powered wheelchair
Actual : Some minor deviations
PASS
Fall 2008Grand Valley State University
Fits Through a DoorFits Through a Door
● Improvements: NoneImprovements: None
Goal : Width < 32" Actual : Width = 30" PASS
30"
Fall 2008Grand Valley State University
BatteriesBatteries
● Improvements: Better compromise between Improvements: Better compromise between price, weight, and electrical capacity.price, weight, and electrical capacity.
Goal : Discharge > 16 hr
Charge < 8 hr
Actual : Discharge >20 hr (1.4 A Draw)
Charge > 10 hr
(BORDERLINE) FAIL
Fall 2008Grand Valley State University
TransportationTransportation
● Improvements: Make the trainer "collapsible" Improvements: Make the trainer "collapsible" into two or more pieces.into two or more pieces.● Aluminum FrameAluminum Frame
Goal: Can fit in trunk Actual: Length and height are too large
FAIL
Fall 2008Grand Valley State University
General ConcernsGeneral Concerns
● JoystickJoystick● Loses calibration resulting in unexpected motion of Loses calibration resulting in unexpected motion of
the trainerthe trainer● Looser spring and better mounting systemLooser spring and better mounting system
● TractionTraction: Cannot turn easily on carpet: Cannot turn easily on carpet● Over-HeatingOver-Heating: Look at controls system: Look at controls system● Battery-Level ReadingBattery-Level Reading: Calibration could be off: Calibration could be off
Fall 2008Grand Valley State University
Proposed New FeaturesProposed New Features
● Attendant ControlAttendant Control● "E-Stop" Bumper"E-Stop" Bumper● Joystick: Joystick:
"Backwards "Backwards Mode"Mode"
● Multiple control Multiple control interfacesinterfaces
Fall 2008Grand Valley State University
BudgetBudget
Part Supplier Supplier Number Cost Qty Total Cost
Motor NPC NPC-B81, -B82 $339.00 2 $678.00
Charger McMaster-Carr 7558K68 $299.03 1 $299.03
Batteries Digi-Key 522-1015-ND $82.51 2 $165.02Acrylic for Joystick and Controls
McMaster-Carr 8774K43 $134.82 1 $134.82
Motor Driver Dimension Engineering
Sabertooth 2x25 $124.99 1 $124.99
Subtotal $1,952.89
+20% (Shipping, tax) $390.58Total $2,343.47
Fall 2008Grand Valley State University
RecommendationsRecommendations
● Patentable?Patentable?
● Continue engineering design workContinue engineering design work
● Perform market studiesPerform market studies
Fall 2008Grand Valley State University
Our RoleOur Role
● Troubleshooting existing features and making Troubleshooting existing features and making recommendations on design changesrecommendations on design changes
● Website: Website: http://sites.google.com/site/pwtgvsu/http://sites.google.com/site/pwtgvsu/● E-mail: E-mail: pwt.gvsu@gmail.compwt.gvsu@gmail.com
Fall 2008Grand Valley State University
Special ThanksSpecial Thanks
● D. Linda BidabeD. Linda Bidabe● Founder of Move International Founder of Move International
● Cathy RipmasterCathy Ripmaster● Lincoln Development CenterLincoln Development Center
● Karen GoraKaren Gora● Mary Free Bed Rehabilitation Hospital Mary Free Bed Rehabilitation Hospital
● Engineering Faculty and StaffEngineering Faculty and Staff
Fall 2008Grand Valley State University