1. P14007: Wheelchair Assist: Detailed Design Review Che-An Lee – Industrial and System Engineer Dan Schuster – Mechanical Engineer Phil Medalie – Mechanical Engineer Tom Elliot – Electrical Engineer

2. Agenda Project Overview Mechanical System Electrical System Assembly Plan Test Plan Risk Assessment Project Timeline

3. Project Overview Assist manual wheelchair users on slopes Mechanical system Ratchet system Brake system Electrical system Charging system Expected outcome Functional prototype Engineering design experience Basis for future senior design project

4. Overview

5. Total System

6. Brake Disc w/Shaft

7. Chair Mount

8. Pawl Mount

9. Ratchet and Pawl Interaction

10. System w/ Washer

11. System w/ End Plate

12. Shaft

13. Electrical Components

14. Attachment to Shaft

15. Critical Component Analysis Shaft Bearing Block Bolts Ratchet Tooth

16. Shaft Analysis

17. Shaft Results

18. Ratchet Tooth Analysis S = 60200 psi F = 0.25 in Y = 0.431 for 72 teeth DP = 24 V  Disregard for low speeds W = 270 lbf of allowable tooth load (will see ~115 lbf)

19. Bolt Analysis Bolt Shear Sy = 70 ksi Ssy = 40 ksi

20. Detailed Electrical Generator Design

21. Bill of Materials DescriptionPart #Cost Cost (1000)QuantityTotalTotal(1000)Link USB Port 87520- 0010BLF $0.71$0.381$0.71$0.38 http://www.mouser.com/ProductDetail/FCI/87520-0010BLF/?qs=x6EjVpvqMVP/2to87x7cdQ== Battery n/a $49.95$39.961$49.95$39.96 http://www.adafruit.com/products/1566#Description Motor Dc Geared 24V 30RPM 30573 $37.03$31.922$74.06$63.84 http://www.digikey.com/product-detail/en/30573/CRA206-ND/186746 Outdoor Speaker Wire 6 feet needed n/a $0.78$0.601$0.78$0.60 http://www.amazon.com/Cables-Waterproof-Speaker-sequential-markings/dp/B008J4XCB8/ref=pd_sim_sbs_e_1 Voltage Regulator 90400 $7.00$5.601$7.00$5.60 http://www.prodctodc.com/dc-35v30v-to-40v30v-converter-auto-boost-buck-voltage-regulators-power-supply-module-p- 67.html#.UqA3IsRDuz6 Bridge Rectifier GBU404 DI-ND $1.37$0.592$2.74$1.18 http://www.digikey.com/product-detail/en/GBU404/GBU404DI-ND/278605 Custom PCB Board(OSH Park) n/a $3.07 1 http://oshpark.com/orders/new/78avpdqg TOTAL$138.31$114.63

22. Buck-Boost Regulator Circuit 5V with 80% Efficiency *Ordered Premade*

23. DC Generator Motor 2.7W 24V 30RPM

24. Battery with Battery Protection 10,000mAh @ 5V Outputs up 2A Draws up to 1A Dimensions: 2.9" x 1" x 4.9" / 72mm x 24mm x 125mm Weight: 300g 80% Efficient

25. Simulation

26. Breadboard Proof of Concept Used a Linear Regulator which is less then 50% efficient Used a Hand Crank motor Used a 3.4V Battery

27. PCB Board Design

28. PCB Product Ready to Be Ordered TopBottom

29. Electrical Energy Harvesting Overview Battery = Average 80% Efficiency Buck-Boost = Average 85% Efficiency Motors = 2.7W each = 5.4W at 30RPM 3.456 W generation at 30RPM 691.2 mA generation at 5V, at 30RPM

30. Benefits to design Easily can covert to AC Motor if Needed. PCB Fits on top of the Buck-Boost Regulator therefore saving space. Battery can be charged by a wall charger too. Arduino boards and other electronics can also be power by battery therefore opening up further applications and not limiting it to phone charging.

31. Cable System

32. Bill of Materials

34. Target vs. Actual Targeted CostActual Cost Ratchet$150$182 Brake$100$146 Charging$250$138 Total$500$466

35. Assembly Plan

36. Test Plan Test Equipment – Plywood base – Car Jack – Cables – Tape Measure – Scale – Multimeter – Fish hook scale or similar – Circuit simulation software Phase of Testing – Component Ratchet System Circuit Design – System Mechanical System Electrical System Usability Testing

37. Risk Assessment

39. Project Future

41. Comments/Questions?

42. Updated Engineering Requirements rqmt. # Import ance SourceFunctionEngr. Requirement (metric) Unit of Measure Margin al Value Target Value Ideal ValueComments/Status S193C13 System Operation Current output to battery at 5V when moving 1 mph Amps0.1250.251 S203C13 System Operation Current output to battery at 5V when moving 4 mph Amps0.514 S213C5 System Portability Ratchet System Weightlbf151210.5 S223C5 System Portability Brake System Weightlbf1087 S233C5 System Portability Charging System Weightlbf252017.5 S249C7 System Operation Rachet System Cost$30015060 Production level costs S259C7 System Operation Brake System Cost$20010040 Production level costs S269C7 System Operation Charging System Cost$500250100 Production level costs S279C1 System Operation Hill Holder Roll back distance in210.5 S283C4 System Operation Wear Item Replacement Time minutes30155 S293C2 System Operation User Input Braking Forcelbf20105