1. Smart Cane IEEE Design Presentation
Lauren Bell, Jessica Davila, Jake Luckman, William McIntyre, Aaron Vogel

2. Introductions Lauren Bell – Mechanical Engineer
Jessica Davila – Industrial Engineer
Jake Luckman – Mechanical Engineer
William McIntyre – Electrical Engineer
Aaron Vogel – Mechanical Engineer

3. Agenda Problem Description Design Challenge Potential Concepts
Critical Design Decisions
Final Concept
System Operation
Testing and Traceability
Project Management
Conclusion
Acknowledgements

4. Problem Description
Safe and easy navigation in the world is difficult for the blind and deaf/blind
Project Goal
Expensive
Training Required
Inexpensive
Intuitive
Limited Situation Feedback
Excellent Situation Feedback
Cane advantages – inexpensive and available , little or no training, users can feel their environment
Disadvantages – slow navigation – cane is only means of judging the environment
Guide dogs advantages – take commands , understand tricky obstacles , guide the user
Disadvantages – expensive , can get sick/hurt, requires a lot of training . Waiting lists for animals are long – not allowed in some areas, user don’t feel their environment
Common solutions
Traditional White Canes
Guide Dogs
Drawbacks and limitations
Need more information about surrounding environment
COMMON SOLUTIONS

5. Design Challenge…
…To design, fabricate, assemble and validate a ‘haptic handle’
To be attached to a traditional cane
Provide directional feedback to blind and deaf/blind users
Just a handle, not a detection system, just ability to connect with
Less expensive
Little training
Can feel the environment and provides haptic feedback
Longer range beyond the tip of the cane

6. Process Overview Concept Selection Design Considerations
Many ideas to one
Design Considerations
Defining the engineering requirements & constraints
Generation of Final Design
Integration of all subsystems
Testing of Prototype
Trace back to engineering requirements

7. Potential Concepts
Brainstorming and benchmarking yielded the following likely candidates…
Track Ball
Piston Push Feedback
Torque ‘Jerk’
Scroll Navigation
Magnetic Force Feedback

8. Narrowing Our Selection
Customer requirements
Vibration Motors
Track Ball Navigation
Piston Push Feedback
Torque ‘Jerk’
Scroll Navigation
Magnetic Force Feedback
Easy to Feel Direction
Datum +
Provides Directional Feedback S
Safe to use
Compact Design -
Lightweight
Affordable within our budget
Fast Response time
Easy for users to learn within our time frame
Able to be used with gloves
After coming up with several concepts, we devised a method of using the PUGH Chart as our ultimate selector of which concept to dive deeper into. We chose the scroll method because it provided the following characteristics which we determined to be better than the first generation prototype:
Easier to determine the directional feedback
Can be used with gloves

9. Scroll Navigation Pros Easier to feel direction
Better directional feedback
Can be used with gloves
Cons
May inhibit index finger haptic ability
Screw-in cap
Battery Housing
Microcontroller
Continuous servo
Scroll Transmission

10. Mock Ups Final Concept Ideas Final Concept Selection
Finger Bump Scroll
Palm Bump Roller
Final Concept Selection
Palm Roller
Palm bump direction was clearly noticeable in comparison to the finger scroll
Finger scroll – difficult to determine direction, desensitizes the fingertip

11. Design Considerations
Customer desires needed to be transformed into technical requirements…
Customer desire
Technical Requirement
Light weight
< 1 lbs.

12. Design Considerations
Pressure on System
Bump Characteristics
Stress
Motor
Power Management
Microcontroller
After deciding on the scroll feedback mechanism concept, we began to dig deeper into the optimal design.
We wrote down and began to assess a variety of analysis areas that we could easily test and optimize.
Microcontroller
Power consumption
CPU Speed
Motors
DC vs Servo
Torque
Weight
Dimensions
RPM
Continuous/Standard
Bump Characteristic
Effective bump speed
Bump geometry
Bump Height
Power Management
Battery Life
Rechargeable vs. Disposable
Size

13. Design Grip Pressure Spec
Ensure handle functions under excessive grip
Measure pressure of displaced air for rough idea
Median pressure ~3 psi
Compare to Grip Pressure Study*
FSR sensors on glove
“Crush grip” measured on 50mm diameter handle
5 male and 5 female adults
Maximum pressure ~3.1 psi
“Crush grip” stronger than pinch and support/carrying
Design made to withstand at least 3 psi.
Tao Guo qiang; Li Jun yuan; Jiang Xian feng, "Research on virtual testing of hand pressure distribution for handle grasp," Mechatronic Science, Electric Engineering and Computer (MEC), 2011 International Conference on, pp.1610,1613, Aug. 201

14. Bump Characteristics Analysis
Comfort
Sensitivity
Motor, bump height, bump frequency, bump geometry, ANOVA analysis and optimization
A series of tests were completed to determine the optimal bump height and bump frequency. Participants were asked to rate the comfortability and how well the rollers provided direction on a scale from 1-5. An ANOVA test along with the Tukey range test on the resulting data. We used this to compare all possible pairs of means and if they were significantly different from each other.
Through testing, effective bump height and speed was determined.

15. Selected motor met all design requirements.
Motor Requirements
Maximum moment occurs when:
Grip reaches maximum design pressure
Pressure force is perpendicular to contact point
Palm contact area is maximum on roller
Two rollers contact the palm
Maximum moment caused by worst case scenario design pressure
50.1 oz-in
The next critical design parameter was the motor torque
We performed loading analysis
Selected motor met all design requirements.

16. Roller Analysis Bumps per rotation Servo to Roller Spacing
Effectiveness of our model – Audience?
Working with the max expected grip pressure and the

17. Roller and Pins Force/Stress Analysis
Rollers and pins withstand force and stress under worst case scenarios.

18. Signal Flow Diagram

19. Micro Family Selection
Arduino
MSP430
Price
$20-100
$3-15
Architecture
8 Bit RISC
16 Bit RISC
Clock Speed
8-16 MHz
8-25 MHz
Stand Alone Capability No
Yes
Maskable Interrupt Lines 2
Power
165mW
.5mW

20. Simulation and Detection System
BJ – to be integrated in future
For now, we just set up simulation

21. Final Concept
Drawing and photograph

22. System Operation Micro controller sends information to PCB
PCB controls motor
Motor turns roller sub assembly
Battery supports total system
Rollers rotate beneath user’s palm indicating the direction to move in
How it works

23. System has passed all tests
Testing and Traceability
System has passed all tests

24. Prototype meets all non-technical requirements
Testing and Traceability
Prototype meets all non-technical requirements

25. Risk Assessment ID Risk Item Likelihood Severity Importance 1
Burning out micro controller 3 2 6
Software is ineffective
Haptic handle and testing systems integration issues 4
Not meeting customer expectations 5
Not obtaining parts on time
Battery malfunction 7
Over budget 8
5 volunteers for user test are not established in time 9
Cane does not stay together, durability failure 10
Not completing software component 11
Haptic forces not being strong enough 12
Hardware and software integration 13
Detection is ineffective 14
Team Member leaves team 15
Cane gets dropped repeatedly on the ground 16
Excessive tapping 17
Handle material is not effective (Tears with consistent wear) 18
Uncoordinated team schedules 19
Selected power and components produce excessive heat 20
Necessary facilities and personnel are not available when needed 21
System is too heavy for desired cane weight

26. All risks were tracked and managed.
Risk Curve
All risks were tracked and managed.

27. Project Plan/Work Dispersion
Project plan was tracked and work was properly distributed .

28. Conclusion
Desired cane handle objective was met

29. Recommendations Complete cane with integration to sensors
Improve handle to provide feedback on changes in elevation and proximity of obstacles.

30. Acknowledgements Guides Customers Professor Mark Indovina
Gary Werth
Gerry Garavuso
Customers
Dr. Patricia Iglesias
Gary Behm
Tom Oh
Professor Mark Indovina
Jeff Lonneville

32. Attractive/Repulsive Magnetism Navigation
Pros
Easier to feel direction
Better directional feedback
Can be used with gloves
Cons
Possible power limitations
No indication of proximity (acting alone)
Screw-in cap
Battery housing
Microcontroller
Wire windings with ferrous cores

33. Piston Navigation Pros Easier to feel direction
Screw-in cap
Pros
Easier to feel direction
Better directional feedback
Can be used with gloves
Cons
Heavier
No indication of proximity (acting alone)
May inhibit index finger haptic ability
Standard servo
Battery Housing
Push piston
Drive shaft
Microcontroller

34. Track Ball Navigation Pros Easier to feel direction
Screw-in cap
Pros
Easier to feel direction
Better directional feedback
Can be used with gloves
Cons
Heavier
Less compact
May inhibit index finger haptic ability
Microcontroller
Battery Housing
Continuous servos & transmission shafts
Track ball

35. Torque Handle Navigation
Screw-in cap
Pros
Easier to feel direction
Better directional feedback
Can be used with gloves
Cons
Heavier
Moment of inertia/torque concern
Transmission
Standard servo
Microcontroller
Battery housing

36. Roller Force/Stress Analysis

37. Force/Stress Cont’d