MSD I SMART CANE INTEGRATION SYSTEM SYSTEMS DESIGN PHASE REVIEW. P15043 October 2, 2014

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Dwayne Fitzgerald
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1 MSD I SMART CANE INTEGRATION SYSTEM SYSTEMS DESIGN PHASE REVIEW P15043 October 2, 2014

2 Agenda Problem Statement Background Team Update Updated Customer Requirements Updated House of Quality (HOQ) System Analysis Concept Selection Proposed Concept Risk Assessment Patents Lessons Learned Next Steps 2

3 Problem Statement Current State: The blind face navigational and safety challenges Current audio feedback solutions have several shortcomings P14043: Prototype not fully functional; extremely fragile Our Mission: Design an assistive device for use by the blind and deaf Integrate existing concepts from P14043 Improve on P14043 s design Assembly process to be performed by blind workers 3

haptic feedback Cons: Fragile/weak structure Sensor system not

4 Background P14043: Smart Cane Pros: Proof of concept Effective haptic feedback Low manufacturing cost Rotating handle section to provide haptic feedback Cons: Fragile/weak structure Sensor system not integrated Loose electrical connections Bulky microprocessor Excess of small parts 4

5 Team Update 2 nd customer interview Tour of ABVI facilities Meetings with individual stakeholders Team building activity It was amazeing! 5

6 Updated Customer Requirements *Customer requirements are ranked by importance 6

7 Updated HOQ 7

8 Pareto 8

9 Pareto Analysis 25% of the engineering requirements contain 66% of the weight for this project Top Four Items Provide 90 degree detection range in front of user Signal detection of obstacles via haptic feedback (horizontal and vertical motion in handle) Horizontal detection range of 6 feet Prototype cost under 1,000 USD 9

10 Functional Decomposition 10

11 Concept Generation Morphological Analysis Concept Generation Pugh Analysis Concept Proposal 11

12 Morph Analysis Concept 1 Concept 2 Concept 3 Sub-function / Cane Component Collapse Cane Handle Only -The rest of the cane collapses Concept Ideas Wired Together Pressure Fit Folding with hinges Screw Connections Sensor Location In Cane Handle On Cane Shaft On Hand Provide Power Rechargeable Battery Solar Outlet Provide Feedback to User Ribbon/Wrist Twist Twisting Handle Roller (Bearing) P14043 Drill Button/Whack- A-Mole Wristbands separate from cane Detect Objects Sonar Optical Ultra-Sonic Infrared Weight Concentration In handle Over Whole Cane 12

13 Concept 1: Roller In Handle Pros: Beta Phase (Continued from last year) Concerns: User feedback awareness User learning curve Versatile cane handling 13

14 Concept 2: Actuated Buttons In Handle Pros: Easy learning curve Feedback awareness Potential to have versatile cane handling Concerns: Handle must be designed carefully to ensure versatile cane handling 14

15 Concept 3: Wrist Bands Pros: Very versatile cane handling Easy learning curve Cons: Potentially costly Potentially time consuming Multiple separate parts Possible to switch wristbands and get incorrect feedback 15

16 Pugh Selection Matrix Number Selection Criteria Datum P14043 Idea 1 Roller in handle Idea 2 Actuated Buttons in handle Idea 3 Wrist Bands 1 Low Cost Doable in 2 Semesters Reliability/Consistency Durability Versatile Cane Handling Light Weight Manufacturability Easy Learning Curve Minimized number of separate components Flexibility of where to put sensors Feedback Awareness Collapsibility Sum + 's Sum 0's Sum -'s

17 Pugh Selection Matrix Number Selection Criteria Idea 1 Roller in handle Idea 2 Actuated Buttons in handle Idea 3 Wrist Bands 1 Low Cost + + DATUM 2 Doable in 2 Semesters Reliability/Consistency Durability Versatile Cane Handling Light Weight Manufacturability Easy Learning Curve Minimized number of separate components Flexibility of where to put sensors Feedback Awareness Collapsibility 0 0 Sum + 's Sum 0's Sum -'s Comparing our 3 concepts to better understand their advantages with respect to each other Number Selection Criteria Idea 1 Roller in handle Idea 2 Actuated Buttons in handle Idea 3 Wrist Bands 1 Low Cost 0 DATUM - 2 Doable in 2 Semesters Reliability/Consistency Durability Versatile Cane Handling Light Weight Manufacturability Easy Learning Curve Minimized number of separate components 0-10 Flexibility of where to put sensors Feedback Awareness Collapsibility 0 0 Sum + 's Sum 0's Sum -'s

Proposed Concept Concept 2 Feedback through actuated buttons on handle What we like about it: Easy to interpret feedback Direction is clear (rollers are not intuitive) Not significant

18 Proposed Concept Concept 2 Feedback through actuated buttons on handle What we like about it: Easy to interpret feedback Direction is clear (rollers are not intuitive) Not significant internal design deviation (motors, wiring) Feasible in two semester schedule Does not require expensive technology (Bluetooth) Trade-offs More moving parts Less flexibility with user grip 18

19 System Architecture Motor Haptic Feedback (User Interface) Micro Processor Battery Sensors Environment 19

20 Feasibility Analysis Question How will the user be effected if the feedback is delayed or not working (connection error/disconnect)? Will the cane be able to be easily collapsed or reassembled in one minute or less? How quickly must feedback be relayed to the user in order to allow them the ability to comfortably react? How does user height affect sensor height on the cane? Will the additional weight of the cane have a significant negative impact on the user? If the sensors are placed lower on the cane will it affect the user more, vice versa? Consideration Type Analysis Benchmarking Analysis Analysis Analysis Analysis Key Topics (Potential faculty correspondence) Feedback to the user (Tom Oh) Sensor location (Tom Oh and Kolodziq / Wellin) Cane weight (Matt Marshall) Cane collapsibility (Matt Marshall) 20

21 Risk Assessment Risk Item Effect Cause General 1 Battery contact is compromised Loss of power Deflection of wire connection User Muscle Fatigue Pain/discomfort to user 3 Over heating Damage to system Harm to user 4 Cane malfunction No feedback delivered to user 5 Misplaced parts User frustration 6 7 Sensors relay incorrect information to feedback Sensors hit obstacles when cane is sweeping Confusion and/or danger to user Damage to sensor Shift in sensor position Sensor falls off How hand grips on handle Weight distribution of cane Likeliho od Importa nce Severity Actions to Minimize Risk Make sure all components that house wires are rigid and secure wires sufficiently for cane movement Ergonomics considered in design Insufficient heat dissipation Perform thermal analysis Component malfunction or damage Multiple unconnected in the system Sensors Sensor malfunction Broken connection Problem with program Design for redundancy Make system all one piece Create a way separate components can be stored together when not in use Test prototype extensively Location of sensors on the cane Attach sensors in the top region of the cane 8 Sensors get dusty/dirty Malfunction Environment encountered Haptic Feedback 9 Water damage Ruined components Not waterproof Loss of haptic motion (when signal is sent from sensors, feedback does not respond with motion) Haptic motion is unclear and not intuitive Feedback is obstructed by clothing or jewelry (ex. Gloves) Feedback not given to user User confusion Learning curve to use cane Decreased feeling of feedback Disconnection of feedback mechanism and motor Burnout of motor Haptic motion design Location where feedback comes in contact with the user State in user manual that sensors should be cleaned frequently Minimize openings Put waterproof cover over feedback Sufficiently secure roller to motor Do analysis to make sure torque is not too high for motor Do thorough testing to make sure haptic feedback relays information clearly to users Brainstorm ways to minimize clothing/jewelry obstruction 21

22 Risk Mitigation Items such as 4 and 10 can be reduced or eliminated through mindful design 4: Cane malfunction 10: Loss of haptic feedback We will actively aim to reduce the number of risks as the project progresses Severity to project outcome will increase if not addressed 22

23 Patents Patent No. US 8,077,020 Method and apparatus for tactile haptic device to guide user in real-time obstacle avoidance. By Gary Behm and Richard Mering 23

24 Patents cont. Patent No. US 7,706,212 B1 Mobility director device and cane for the visually impaired By Terry Campbell 24

25 Patents cont. Patent No. US 7,755,744 B1 Environment sensor that conveys information about objects in the vicinity of the visually impaired user. By Thomas Leberer 25

26 Patents cont. Patent No. US 8,823,389 B1 Mobility device and method for guiding the visually impaired By Terry Campbell and Eric Karich 26

27 Lessons Learned Pugh chart and feasibility analysis helped to: Expose areas to address in our risk assessment and mitigation plan Highlighted gaps in our expertise Customer communications are critical in the design process Better coordinate project work with team member s schedules 27

28 Schedule Phase III 28

29 Next Steps High Level 29 Select system design based on phase II review Test Plan System Level High risk sub-systems Proof of Concept (POC) Design review with appropriate RIT faculty

30 Questions 30

31 Feasibility Analysis: Question 1 How will the user be affected if the feedback is delayed or not working (connection error/disconnect)? Assumptions: User uses cane regularly User checks to makes battery is charged Battery is on Connections are completely plugged in Problem: If cane is not working properly, there is no mechanism to communicate this back to the user Conclusion: Feedback should be put in the cane to alert user that there is a connection error/disconnect. 31

32 Feasibility Analysis: Question 2 Will the cane be easy to collapse or reassemble in one minute or less? Assumptions User understands how the cane should be folded before performing this task User has the motor skills necessary to perform the task User is in a reasonable environment to be performing this task (i.e. No extreme temperatures) No tools will be required for the task Benchmarking Collapsible Canes Option Estimated Time Notes 1. Folding (elastic) 7 seconds Time would be much longer for a nonexperienced user 2. Push button to open 3 seconds Assumes one connection 3. Cane couplers 2 seconds Time is per connection 32

33 Feasibility Analysis: Question 2 Will the cane be easy to collapse or reassemble in one minute or less? Figure 1. Folding Cane (7 sec) Figure 2. Push Button Cane Figure 3. Cane Couplers (2 sec per connection) 33

Feasibility Analysis: Question 3 How soon must feedback initiate to allow time for user to react? Assumptions: User will be traveling at an average of 3 mi/hr (1.

34 Feasibility Analysis: Question 3 How soon must feedback initiate to allow time for user to react? Assumptions: User will be traveling at an average of 3 mi/hr (1.34 m/s) Feedback is provided instantly The amount of time it takes to react to stimuli by clenching a fist is equal to the time it takes to react by changing course. The amount of time required for the brain to receive feedback from tactile stimuli at the hand and shoulder are the same. Equations Used: (sites.google.com/site/danielassupercoolbiologylab/) x = average distance lapse between stimuli and fist clench = m x = 1 2 at2 t = 2x a = = 0.21 s Results: β = β m β = cane time delay Conclusion: The minimum distance between the user and an obstruction before the cane initiates haptic feedback is 0.28 m. Additional space is to account for cane delay.* *Values calculated are worst-case minimum values. Additional space is necessary for practical use. 34

Arm length for 5 and 6 person is 19 and 26, respectively. Equations Used: Law ofsin: a sinα = b sinβ Trig Equation: sinθ = y r Results: H5 = 17.4 =Sensor Height for 5 person H6 = 18.

35 Feasibility Analysis: Question 4 How does user height affect sensor height? Background: Most typical canes are sold in varying lengths. Assumptions: Sensor is in the middle of the cane Cane length: 52 (middle value) Height of armpit for 5 and 6 person is 47 and 56, respectively. Arm length for 5 and 6 person is 19 and 26, respectively. Equations Used: Law ofsin: a sinα = b sinβ Trig Equation: sinθ = y r Results: H5 = 17.4 =Sensor Height for 5 person H6 = 18.7 =Sensor Height for 6 person Therefore the sensor for the 5 person will only be 1.3 lower than the sensor for the 6 person. It was expected the sensor for the 6 person would be significantly higher, but their extra arm length helps keep the sensor lower. Conclusion: For future sale of the cane varying cane lengths should be considered, but the height of the sensors on the cane prototype should be fairly similar. 35

36 Feasibility Analysis: Question 5 Will the additional weight of the cane have a significant negative impact on the user? Assume: Additional weight is centered Height (bottom of foot to top of head): H=2m m=.454kg θ=45 degrees mg Additional Moment = cos45.36(2m) (.454kg)( 9.8m s 2 ) = 2.27Nm θ What does this mean? 36

Feasibility Analysis: Question 6 How much is the user effected if the sensors are placed at the bottom, compared to them being placed near the top.

37 Feasibility Analysis: Question 6 How much is the user effected if the sensors are placed at the bottom, compared to them being placed near the top. Assumptions: Center of gravity is where the cane is held/handle. It is being held at a 45degree angle at all times. Average weight of cane handle: 3 lbs Average weight of sensors:.25 lb Equations: Center of mass of regular cane: 0.5ft Center of mass with sensors near handle: 1ft Center of mass with sensors near tip: 2.75ft 37

38 Updated Engineering Requirements Rqmt. # Importance Source Function Engr. Requirement (metric) Unit of Measure Marginal Value S1 9 CR1 System Operation Provide 90 degree detection range in front of user Degrees 90 S2 9 CR1 Signal detection of obstacles via haptic feedback (horizontal and System Operation vertical motion in handle) Binary S3 3 CR2 System Portability Adds no more than 1 lb. to standard white cane Lbs. 1 S4 3 CR3 System Assembly Decrease number of existing parts by ~50% or more Pieces S5 3 CR4, CR5 System Operation 8 hour rechargeable battery (minimum battery life) Hours 8 S6 3 CR6 System Portability Collapsible into 8-10" sections Inches 10 8 S7 3 CR7 System Cost Manufacturing cost $125 or less USD 125 Design assembly process to be completed in a blind assembly S8 1 CR8 System Assembly environment Binary S9 3 CR9 System Usability Keep cane collapse/re-open time less than 1 minute Minutes 1 S10 9 CR10 System Operation Horizontal detection range Feet 6 10 S11 9 PRP N/A Prototype cost USD 1000 <1000 S12 3 CR12 System Operation Maximum pressure psi 3 5 S13 3 Time from motor input signal to when the roller reaches the CR10 System Operation minimum rotation speed at 3 psi Grip ms 500 <400 S14 3 CR11 System Safety Circuit voltage V 12 <12 S15 3 CR12 System Structure Handle contents fit within handle mock up envelope Binary Pass Pass S16 9 CR12 System Structure Maximum handle grip diameter in Importance: Sample scale (9=must have, 3=nice to have, 1=preference only), or see Ulrich exhibit 4-8. Ideal Value 38

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