Eric Domke
                                                          Drew Pretzer
                                        ...
Introduction

     ●   Project Description
     ●   Customer Needs
     ●   Specifications
     ●   Design Evolution
     ...
Problem Description

     ●   Must pass test to get
         money from insurance
         company
     ●   Not enough pra...
Target Market




Grand Valley State University      Fall 2008
Customer Needs - Interviews

     ●   Fit through a standard door
     ●   Change between different wheelchairs quickly
  ...
Product Specifications

     ●   Switch Users in Under 5 Minutes
     ●   Accommodate Different Sized Wheelchairs
        ...
Revision A

                                ●   Motor Calculations
                                    Torque        480.9...
Revision B

                                    Front of
                                    Trainer




                 ...
Revision C
                                ●   Motor Testing
                                    ●   Cordless motors possi...
Revision D
                                ●   Finite Element Analysis
                                    ●   Need multip...
Revision E
                                            ●   Site Visit to LDC #2
                           Motors
        ...
Final Design




Grand Valley State University     Fall 2008
LDC – Final Visit




Grand Valley State University          Fall 2008
Loading




  Goal : "Not Strenuous"        Actual : Very Easy   PASS
     ●   Improvements: None

Grand Valley State Univ...
Locking




     Goal : < 5 minutes         Actual : < 1 minutes   PASS
     ●   Improvements: None

Grand Valley State Un...
Maneuverability




 Goal : Similar to powered      Actual : Some minor   PASS
        wheelchair                  deviati...
Fits Through a Door




                                                30"



      Goal : Width < 32"        Actual : Wi...
Batteries




  Goal : Discharge > 16 hr Actual : Discharge >20 hr   (BORDERLINE) FAIL
                                 (1...
Transportation




     Goal: Can fit in trunk     Actual: Length and     FAIL
                                height are ...
General Concerns

     ●   Joystick
          ●   Loses calibration resulting in unexpected motion of
              the tr...
Proposed New Features

     ●   Attendant Control
     ●   "E-Stop" Bumper
     ●   Joystick:
         "Backwards
        ...
Budget

                  Part            Supplier      Supplier Number    Cost     Qty   Total Cost

      Motor         ...
Recommendations

     ●   Patentable?

     ●   Continue engineering design work

     ●   Perform market studies




Gran...
Our Role

     ●   Troubleshooting existing features and making
         recommendations on design changes
     ●   Websit...
Special Thanks

     ●   D. Linda Bidabe
          ●   Founder of Move International
     ●   Cathy Ripmaster
          ● ...
Grand Valley State University   Fall 2008
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Pwt Final Presentation

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Powered Wheelchair Trainer Final Design Presentation

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Pwt Final Presentation

  1. 1. Eric Domke Drew Pretzer Brandon Rood Karl Hiedemann Powered Wheelchair Trainer Design Project Fall Semester - 2008 “The ability to move is the first foundation stone in building personal dignity.” - D. Linda Bidabe Grand Valley State University Fall 2008
  2. 2. Introduction ● Project Description ● Customer Needs ● Specifications ● Design Evolution ● Demonstration & Evaluation of Prototype ● Recommendations Grand Valley State University Fall 2008
  3. 3. Problem Description ● Must pass test to get money from insurance company ● Not enough practice ● Powered chairs are expensive ● Goal: Build "inexpensive" device which attaches to manual wheelchairs. Grand Valley State University Fall 2008
  4. 4. Target Market Grand Valley State University Fall 2008
  5. 5. Customer Needs - Interviews ● Fit through a standard door ● Change between different wheelchairs quickly ● Easily transportable between different buildings. ● Good battery life. Grand Valley State University Fall 2008
  6. 6. Product Specifications ● Switch Users in Under 5 Minutes ● Accommodate Different Sized Wheelchairs ● Widths of 20-25 inches ● Lengths of 32-50 inches ● Wheelbase of 16-32 inches ● Fit Through a Standard Door ● Width is under 32 inches ● Mimic a Powered Wheelchair Grand Valley State University Fall 2008
  7. 7. Revision A ● Motor Calculations Torque 480.98 In-lb 54.31 N-m (Driving) Torque 209.49 In-lb 23.65 N-m (Steering) ● Support Bar Calculations ● 0.065" Wall Thickness for Steel Tube ● Force to Load Calculation ● 170 lbs ● Tipping Calculation ● Need to move > 9.33" off center Grand Valley State University Fall 2008
  8. 8. Revision B Front of Trainer 1 2 3 Grand Valley State University Fall 2008
  9. 9. Revision C ● Motor Testing ● Cordless motors possible, but durability and brake concerns ● Frictional Force Experiment ● Approx. 300 lbf to get a 4" dia. wheel over a 0.75" ledge Grand Valley State University Fall 2008
  10. 10. Revision D ● Finite Element Analysis ● Need multiple gussets to minimize deflection ● Frame Design Analysis ● Tube frame is stronger and more cost effective Grand Valley State University Fall 2008
  11. 11. Revision E ● Site Visit to LDC #2 Motors ● Motors cannot go between Batteries wheelchair wheels. ● Traction Analysis ● Issues with traction, especially on carpet. Grand Valley State University Fall 2008
  12. 12. Final Design Grand Valley State University Fall 2008
  13. 13. LDC – Final Visit Grand Valley State University Fall 2008
  14. 14. Loading Goal : "Not Strenuous" Actual : Very Easy PASS ● Improvements: None Grand Valley State University Fall 2008
  15. 15. Locking Goal : < 5 minutes Actual : < 1 minutes PASS ● Improvements: None Grand Valley State University Fall 2008
  16. 16. Maneuverability Goal : Similar to powered Actual : Some minor PASS wheelchair deviations ● Improvements: Tweak the controls algorithms and deal with traction issues. Grand Valley State University Fall 2008
  17. 17. Fits Through a Door 30" Goal : Width < 32" Actual : Width = 30" PASS ● Improvements: None Grand Valley State University Fall 2008
  18. 18. Batteries Goal : Discharge > 16 hr Actual : Discharge >20 hr (BORDERLINE) FAIL (1.4 A Draw) Charge < 8 hr Charge > 10 hr ● Improvements: Better compromise between price, weight, and electrical capacity. Grand Valley State University Fall 2008
  19. 19. Transportation Goal: Can fit in trunk Actual: Length and FAIL height are too large ● Improvements: Make the trainer "collapsible" into two or more pieces. ● Aluminum Frame Grand Valley State University Fall 2008
  20. 20. General Concerns ● Joystick ● Loses calibration resulting in unexpected motion of the trainer ● Looser spring and better mounting system ● Traction: Cannot turn easily on carpet ● Over-Heating: Look at controls system ● Battery-Level Reading: Calibration could be off Grand Valley State University Fall 2008
  21. 21. Proposed New Features ● Attendant Control ● "E-Stop" Bumper ● Joystick: "Backwards Mode" ● Multiple control interfaces Grand Valley State University Fall 2008
  22. 22. Budget 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 $165.02 Acrylic for Joystick McMaster-Carr 8774K43 $134.82 1 $134.82 and Controls Motor Driver Dimension Sabertooth 2x25 $124.99 1 $124.99 Engineering Subtotal $1,952.89 +20% (Shipping, tax) $390.58 Total $2,343.47 Grand Valley State University Fall 2008
  23. 23. Recommendations ● Patentable? ● Continue engineering design work ● Perform market studies Grand Valley State University Fall 2008
  24. 24. Our Role ● Troubleshooting existing features and making recommendations on design changes ● Website: http://sites.google.com/site/pwtgvsu/ ● E-mail: pwt.gvsu@gmail.com Grand Valley State University Fall 2008
  25. 25. Special Thanks ● D. Linda Bidabe ● Founder of Move International ● Cathy Ripmaster ● Lincoln Development Center ● Karen Gora ● Mary Free Bed Rehabilitation Hospital ● Engineering Faculty and Staff Grand Valley State University Fall 2008
  26. 26. Grand Valley State University Fall 2008

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