P11017: Tactile Navigation Interface

1. P11017: Tactile Navigation Interface Christian Seemayer Rob Proetti Tim DeBellis Tim Giguere Will Kelly

2. Design Review Outstanding Issues • How does the device tactile perception become affected due to device and strap sensations? • Orientation of Servos as a perfect diamond • Stress Analysis • Housing displacement should allow translation • Servo-Arm stress due to Servo stall torque • Fatigue Analysis • Endurance Limit for Aluminum • Electrical Analysis concerns • PCB board with test points at all nodes • Size of PCB traces depending on current • 45° angles for PC trace corners • Battery Life based on % used during day • Use of keypad interrupts instead of polling • Heat Generation from internal components • Test Plan updates • MSD II schedule changes

3. Device and Strap Sensation Effects • Meeting at ABVI on 2/18/2010 with Alexis Read and Richard • What we discussed • Retested more tip designs out of curiosity with preference being large bowl shape (Screw head) • Concept of generating diagonal directions through pulsing • Directional Testing (2 Tests) • Basic Test • Armband and weight applied Test

4. What We Learned • Results: 100% accuracy from participants. • Extra sensations demonstrated no effect on accurate direction interpretation. • Direction recognition training quicker then expected. • Short (~1 minute)training period • Proper Training approach – Diamond Construction • Participants disliked diagonal direction idea • 4 directions good, 8 creates confusion. • Revamped analysis based on recommendations from Design Review • Put tiny clear dots on the buttons (For sale in Vision Shop at ABVI, 6 dots for $2)

5. Tip Redesign after ABVI visit • Switch from sharp point to more circular area. • Advantages • More blunt surface • Enables more pressure on skin • Larger surface makes it more perceptible to user

6. Adjustment of Servo Orientation • Servos oriented to create perfect diamond • Required pegs to be different lengths

7. Stress Analysis: Housing • Device Housing • Switched boundary condition from All DOF to fixed displacement in load direction • Accounted for translation that can occur. • Servo-Arm • Accounted for servo stall torque

8. New Housing Stress • In the Bottom: 482 psi

9. Servo-Arm Stress Analysis • Ignoring Stress Concentration • Stress of 6,637 psi • Deflection of 5.775e-3 inches

10. Servo-Arm Hand Calculations

11. Fatigue Analysis

12. PCB Board Re-design

13. Battery Life Analysis

14. Motor Control Circuitry Analysis

15. Motor Control Circuitry Analysis

16. Motor Control Circuitry Analysis

17. Motor Control Circuitry Analysis

18. Servo Control Schematic

19. MCU/Power Unit Schematic

20. Team Interfacing Data • Completely new document • Review posted document on EDGE under Miscellaneous Documents

21. Heat Generation Effects

22. Test Plan Updates • Listed engineering specifications correlated to each test • Can be found under test description and on Specs Page • Addition of Test #3 – Electronic Component Testing • Aims to test individual components to ensure proper functioning before beginning assembly period • Eliminated Destructive Tests (Device Drop and Compression) • Moved up test dates in schedule • Rearranged testing order to account for test with similarities • Direction Relay Test to be conducted with Servo Positioning Test • On/Off Switch Test to be conducted in Week 2 or 3 based upon assembly

23. MSD II Updates • Test Plan Date updates incorporated directly into schedule • Created a more specific focus on machining of components • Created a focus toward part assembly times for both mechanical and electrical components • Rough Draft of paper to be started Week 3 • 75% complete by Week 8 • Final draft by Week 9 • Rough Draft of Poster constructed for Imagine RIT • To be finalized during Week 10 • Project Plan for MSD I has helped define each member’s role within the team and establish reasonable goals

24. Evolution of Overall Project Plan • Driven to focus on customer needs • Created specific and sometimes last minute alterations • Altered to account for switches in project design • Accounted for simplification of overall project goal • Device becoming stand alone with self inputs

25. Risk Assessment Updates • Thermal Effects • Electronic components fail to work • PCB does not act with circuit • Circuit does not match PCB • Outside tactile sensation impede user perception of directions • System noise distorts system signals

26. Final BOM

27. Where do we go now? • At ABVI meeting, design was discussed to ensure customer needs were still satisfied • All standing issues have been reanalyzed in the presentation • Design subsystems were reviewed and updated as a result • Currently all documentation is available on EDGE • From the BOM • What is available here at RIT and where? • What do we have to order? • Non-issues • Small lead times for parts (1 week is maximum) • Testing can begin as soon as components gathered • Current cost is far below $1,500 budget, currently only $428.31 • Is the project a “Green Light?” • If yes, when can we begin ordering?