Systems Design Reviewedge.rit.edu/content/P15044/public/Documentation/Phase Review... · Systems Design Review P15044 Intelligent Mobility Cane Allan Andranikian Marisa Ashour

Systems Design Review P15044 Intelligent Mobility Cane Allan Andranikian Marisa Ashour Dan Chianucci Andrew Greeley Justine Nichols Ben Stewart

P1

50

44

System

s Lev

el Rev

iew

Agenda • Project Overview

• Project Background • Deliverables • Customer Requirements • Engineering Requirements • House of Quality

• Functional Analysis • Functional Decomposition • Function-Requirement Mapping • Functional Architecture

• Research • Benchmarking • Background Research

P1

50

44

System

s Lev

el Rev

iew

• System Analysis • Morphological Table • Preliminary Concepts • Concept Selection Process • Pugh Charts • System Architecture • Morphological Elimination • Power Feasibility • Weight Feasibility

• Risks and Next Steps • Test Plan • Risk Analysis • Risk Management • 3 Week Plan • Action Items • Lessons Learned

Project Background • A ‘Smart Cane’ is a device

that is designed to improve the usage of a mobility cane by the visually impaired.

• Our team aims to build an Intelligent Mobility Cane that detects obstacles and drop offs in front of the user and provides haptic (vibrational) feedback while being low-cost.

P1

50

44

System

s Lev

el Rev

iew

Deliverables

• A prototype that fulfills all Customer Requirements

• User’s Guide for the prototype • Engineering documentation for the

reproduction of the prototype (Bill of Materials, Test Plan, etc.)

P1

50

44

System

s Lev

el Rev

iew

Customer Requirements Customer Rqmt. # Importance Description

C1 3 Accurately detects overhangs, obstacles, and walls

C2 3Accurately detects drop offs in front of the cane through a

swept arc

C3 3 Adequate detection range

C4 3 Haptic feedback

C5 3 Low manufacturing cost

C6 2 Easy user assembly

C7 2 Lightweight

C8 2 Long battery life

C9 2 Ergonomically designed for the average American male

C10 1 Rechargeable

C11 1 Cane collapses for easy storage

IMPORTANCE

LEGEND

HIGH 3

MEDIUM 2

LOW 1

P1

50

44

System

s Lev

el Rev

iew

Engineering Requirements rqmt. # Importance Source Function Engr. Requirement (metric) Unit of Measure

Minimum

Value

Target

Value

Maximum

Value

S1 3 C1 Detection Differentiates between obstacles, overhangs, and walls yes/no

S2 3 C1 Detection Response time seconds 0 0.25 1

S3 3 C1 Detection

Percentage of false negatives/positives (accuracy of

detection) % 0 5 10

S4 3 C2 DetectionDetects drop offs in front of the cane through a swept

arcyes/no

S5 3 C3 Detection Detection range (length) feet 6 7 13

S6 3 C3 Detection Detection angle/arc (at maximum length) degrees (°) 2 3 3

S7 3 C4 Feedback Percentage of feedback correctly interpreted by user % 80 90 100

S8 3 C5 Fabrication Materials cost $ 0 125 125

S9 2 C6 Use User assembly time seconds 30 60 90

S10 2 C7 Fabrication

Maximum weight of feedback and detection

components ounces 4 4 16

S11 2 C8 Battery Battery life hours 8 8 /

S12 2 C9

Dimension

s Cane length (when in use) centimeters 129 134 139

S13 2 C9

Dimension

s Cane handle circumference centimeters 10.8 11.4 12

S14 1 C10 Battery Battery recharge cycle hours 2 2 3

S15 1 C11 Storage Cane length (when collapsed) centimeters 0 20 20

S16 1 C11 Storage Cane width (when collapsed) centimeters 0 20 20

yes

yes

P1

50

44

System

s Lev

el Rev

iew

IMPORTANCE LEGEND

HIGH 3

MEDIUM 2

LOW 1

House of Quality P

15

04

4

Sy

stems L

evel R

eview

Major Takeaway from House of Quality: The deflection angle arc is the most important engineering requirement, as it maps to all of the critical customer requirements.

Functional Decomposition P

15

04

4

Sy

stems L

evel R

eview

Constraints: •

Function – Requirement Map Function Customer Requirement Engineering Requirement

Enable navigation of the external environment ALL ALL

Differentiate between different types of obstacles C1,C2 S1, S4

Detect obstacles C2, C3 S2, S3, S4, S5, S6

Provide feedback C4 S7

Provide ability to use and store cane C6, C7, C8, C9, C10, C11 S9, S10, S11, S12, S13, S14, S15, S16

P1

50

44

System

s Lev

el Rev

iew

Functional Architecture P

15

04

4

Sy

stems L

evel R

eview

The cane will be split into multiple subsystems:

• Power Distribution: Provides power and

recharges the battery

• Detection: Senses obstacles and drop offs.

• Processing: Interprets sensors and determines the correct feedback

• Feedback: Produces the vibration felt by the user

• Enclosure: Secures other subsystems in place

Cane Benchmarking Brand Ambutech Drive Medical ILA NFB Revolution WCIB

Model GG3040W-90-4 10352-1 MIN100 8498(inches) #REV-4 #WCPB

Seller Ambutech Medihub USA/ Amazon Independent Living Independent Living Independent Living Independent Living

Diameter .5 inch .5 inch Not Listed .25 inch Not Listed Not listed

Lengths 36"-60" (in 2 " inc) OR 90-150 cm( in 5 cm

inc) 46 1/4 inches 48" 32"- 61"(2 in inc) 36"-44" (2 in inc) 26"-60" (2 in inc)

Cost 18 + $10 SH + $2 TX= $30 $13.89+ FREE SH+ $2 TX=

$15.89 $39.95 +FREE SH+ $2 TX=

$41.95 $25 + FREE SH+ $2 TX= $27

$36.95+ FREE SH+ $2 TX= $38.95

$24.95+FREE SH + $2TX= $26.95

Weight Not Listed .18 lbs Not Listed Not Listed Not Listed Not listed

Material Aluminum Aluminum Carbon Fiber Fiberglass Graphite Aluminum

Shipment Location Winnipeg, MB Canada Crosby Texas, US Buffalo, NY US Buffalo, NY US Buffalo, NY US Buffalo, NY US

Collapsibility 4 different section selections 4 sections Telescoping to 8.75" NO 4 Sections NO

Features Tight Fitting Joints,

Hook and Slip on Tips Available Comes w/strap,

tape for night visibility Fits in backback, Travel

size Durable Flexible, Rubber Handle

Straight or Curved Handle, Long life

Tip Material Several Different Choices Available Nylon Nylon Carbon Fiber Long Life Polymer Nylon

Color 12 colors available Red White/black Silver/black Red/White/Black Silver/Black/Red

P1

50

44

System

s Lev

el Rev

iew

Sensor Type Benchmarking

Parameter IR sensor Ultrasonic sensor (transducer) Laser sensor

light type infrared n/a laser (visible spectrum)

light frequency 300 GHz - 430 THz n/a 430 - 790 THz

sound frequency n/a >20 kHz n/a

typical maximum range 5+ ft 10+ ft 100+ ft.

typical average cost $5-$20 $25+ $50+

expected interference can be influenced by indirect and direct sunlight can be influenced by the reversing sensors in

some cars and other sensors

can be influenced by light of a similar wavelength, which is

common.

P1

50

44

System

s Lev

el Rev

iew

IR Transmitter Benchmarking Parameter IR Distance Sensor (TX + RX) IR emitter (TX only)

Typical Drive Current (mA) 30 Anywhere between 50 and 500

Supply voltage (V) 4.5 to 5.5 3 to 5

Range of detection (m) 1 to 5 in ideal conditions Up to 5 depending on sensitivity and LED type

Emission angle (°) between 15 and 60 depending on narrow or wide-

beam

Cost ($) 24.95 0.005

Part Availability Available through multiple sources Available through multiple sources

Ease of implementation modular, only would need to do signal processing and minimal

conversion through circuitry would need driver circuitry , in addition to a separate

receiver module

P1

50

44

System

s Lev

el Rev

iew

IR Receiver Benchmarking Parameter Passive IR Thermocouple Intrinsic Extrinsic

Detection Mechanism Energy detection and use of

signal processing Converts temperature to

electrical signal Photoconduction/Photovoltaics Photoconduction

Operating Temperature (°C) Range of -40 to 60 Range of 0 to 60 Range of -50 to 600 (depending

on type) -260

Detection range Infrared detectors used for

motion detection can reach up to 15ft in low sensitivity modes

Mostly used to detect objects at close range, no more than 1-2"

away from point of measurement (Part availability is low) (Part availability is low)

Cost $200 (Part availability is low) (Part availability is low)

Weight (oz) >.25 ≤1 (Part availability is low) (Part availability is low)

P1

50

44

System

s Lev

el Rev

iew

Ultrasonic Sensor Benchmarking MB7267 MB1010 UM30-21511

USTR40-14A

(no driver)

Cost $99.95 $29.95 Upon Request ($100+) $5.90 + driver circuitry (

Drop-off Detection Benchmarking

IR Ultrasonic (Stereo Setup) Thermal 2*IR + Ultrasonic

Cost ~$15 ~$50 $2,500+ $83

Response Time 40mS 50mS 33mS 50mS

Accuracy Testing Required Testing Required Testing Required Testing Required

Max Range 4ft 8ft 35ft 8ft-Ultrasonic

4ft- IR

Power Consumption 150mW (can PWM IR for lower

consumption) 25mW 65W

400mW (can PWM IR for lower

consumption)

Weight 0.2oz 0.4oz ~20lbs 0.8oz

P1

50

44

System

s Lev

el Rev

iew

Drop-off Detection Research P

15

04

4

Sy

stems L

evel R

eview

Source What we learned

“Nighttime Negative Obstacle Detection For Off-road Autonomous

Navigation”

Thermal imaging is great at drop-off detection, but is not feasible for our

application.

“An Inexpensive, Alternative Drop-off Detection Solution”

IR sensors are feasible to use for short range drop-off detection.

“Advanced Augmented White Cane with Obstacle Height and Distance

Feedback”

Battery Benchmarking Battery Type

Parameter Lithium ion Lithium polymer Nickel cadmium Nickel metal hydride

Rechargeable (yes/no) yes yes yes yes

Average number of charge cycles (#) 400 - 1200 500 - 1000 2000 500 - 2000

Charge/discharge efficiency (%) 80 - 90 97 - 99 70 - 90 66

Nominal cell voltage (V) 3.2 or 3.7 3.6 1.2 1.2

Average capacity range (mAh) 2500 - 3300 1500 - 2700 2000 - 3000 1300 - 2900

Part Availability (high/low) high high high high

Weight Lithium ion and lithium polymer are mostly comparable in weight

20% lighter than conventional batteries

Heavier than Nickel metal hydride Heavier than lithium-ion/lithium

polymer

Memory effect no no yes no

Weight energy density (Wh/Kg) 125 170 50 80

Volume energy Density (Wh/l) 320 400 150 200

Self discharge (%/month) 9 5 25-30 30-35

Average cost ceiling ($)

Feedback Benchmarking P

15

04

4

Sy

stems L

evel R

eview

Morphological Table P

15

04

4

Sy

stems L

evel R

eview

Preliminary Concepts Concept #

Team

Definition

Detect

obstacles

Detect

drop offs

Provide

feedbackProcess detection

Enclose

system

Power

system

Recharge

systemCollapse cane

1 Best Guess Ultrasonic IR ERM MCUModular

one unitLiPO USB tent pole

2 Cheapest IR IR Voice coil MCU

Modular

multiple

unit

LiPO USB tent pole

3 Lightest no effect no effect piezo no effect single unit LiPO no effectmanually

telescope

4Highest

PerformanceUltrasonic IR piezo FPGA no effect LiPO wall wort

automatically

telescope

5 Easiest Ultrasonic IR ERM MCU single unit no effect wall wort tent pole

P1

50

44

System

s Lev

el Rev

iew

Selection Criteria • Response Time • Cost • Weight • Power Consumption • Sensor Accuracy • Feedback Amplitude • Part Availability • Ease of Mechanical Implementation • Ease of Electrical Implementation

P1

50

44

System

s Lev

el Rev

iew

Pugh Charts P

15

04

4

Sy

stems L

evel R

eview

System Architecture P

15

04

4

Sy

stems L

evel R

eview

• Obstacle detection: Ultrasonic • Drop off detection: Infrared • Provide feedback: ERM • Process detection: MCU • Enclose system: Modular one unit or single unit • Power system: LiPO • Recharge system: USB or wall wort • Collapse cane: tent pole

Morphological Elimination P

15

04

4

Sy

stems L

evel R

eview

Power Feasibility Conservative Power Estimates

Component Voltage (V) Current (mA)

Ultrasonic Sonic Up 5 20

Ultrasonic Sonic Front 5 20

IR Dropoff 5 30

MCU 3.3 10

ERM 1 3.3 54

ERM 2 3.3 54

ERM 3 3.3 54

Misc 3.3 60

P1

50

44

System

s Lev

el Rev

iew

Power Feasibility Cont.

Regulators 85% Efficiency

Efficiency 85 %

Power Consumption

3.3V 880.4 mW

5V 402.5 mW

Total 1282.9 mW

Needed Capacity 10263.5 mWh

2773.9 mAh

# of Batts Needed 2

Battery Life Requirement: 8 Hours LiPo Cell Voltage: 3.7V LiPo Cell Capacity: 1500mAh

P1

50

44

System

s Lev

el Rev

iew

Regulators 60% Efficiency

Efficiency 60 %

Power Consumption

3.3V 1071.8 mW

5V 490.0 mW

Total 1561.8 mW

Needed Capacity 12494.7 mWh

3376.9 mAh

# of Batts Needed 3

Weight Feasibility

*Note: Misc. is a safe estimate for total weight of smaller components such as resistors, the circuit board, and wires.

Weight Contributors

Quantity weight (oz.)

Battery (18650) 2 2

Enclosure 1 Best Estimate

ERM 3 0.1

Ultrasonic Sensor 2 0.5

Infrared Sensor 1 0.2

Misc.* N/A 1

Total Weight 7oz + Enclosure

Target Weight 6oz

P1

50

44

System

s Lev

el Rev

iew

Cost Feasibility P

15

04

4

Sy

stems L

evel R

eview

Option: Cheapest

Component Type Price

Cane Base Drive Medical $15.89

Obstacle Detection 3*IR $45

Feedback 3*Cheapo ERM $7.50

Process Detection 32-bit MCU $10

Power System 3*LiPO cells $25

Recharge System wall wort/USB $7

Total: $110.39

Option: Most Expensive


Cane Base Revolution 38.95

Obstacle Detection 3*Ultrasonic 120

Feedback 3*Precision Microdrives ERM $24.00




Total: $219.95

Option: Ideal/ Midcost


Cane Base Ambutech $30

Obstacle Detection 2*Ultrasonic, 1*IR $95

Feedback 3*Precision Microdrives ERM $19.50




Total: $182

Test Plan Stress Test Vibrating Actuator: • Continuous use shouldn’t negatively affect the transducer • Run motor at max draw for 8hrs while monitoring vibrational intensity and

temperature Test Battery Life: • Battery should last 8 hrs. of continuous current draw • Attach a dummy load to the battery and monitor the battery’s charge level Test Feedback Intensity: • Vibration must be easily detectable by users • Blindfold user and ask them to indicate when the cane is vibrating Test Sensor Response • Sensors to detect the required obstacles at a range of 6ft • Move objects into and out of range and record the sensor’s response times.

P1

50

44

System

s Lev

el Rev

iew

Risk Analysis P

15

04

4

Sy

stems L

evel R

eview

Risk Analysis- Con’t P

15

04

4

Sy

stems L

evel R

eview

3 week vision / updated plan P

15

04

4

Sy

stems L

evel R

eview

Systems Design Review

Subsystems Design Review

Action Items • Update Project Documents based on Feedback :Justine -10/3 • Begin Draft Bill of Materials : Justine, Marisa – 10/7 • Order First Parts for First Cut Testing: Andrew, Ben - 10/9 • Verify final decisions for enclosing and recharging the systems:

Allan, Dan- 10/13 • Conduct surveying with visually impaired individuals about

preferred haptic feedback. : Team- 10/25 • Reference the research from previous Multidisciplinary Senior Design

teams.

P1

50

44

System

s Lev

el Rev

iew

Lessons Learned • Sometimes instincts about implementation are not correct.

• IR is not necessarily ruled out for detection. • Piezoelectrics are more difficult to implement than anticipated.

• Customer Requirements are not static. • Extensive research is needed to verify that referenced material

is correct. • Information about use of piezoelectrics for haptic feedback is

conflicting.

P1

50

44

System

s Lev

el Rev

iew

Questions?

Image Processing Benchmarking

Characteristic University of Stuttgart NAVI University of Guelph TVS Tyfos FIU CompVision

Detects front obstacles Y Y Y Y Y Y

Detects drop-off obstacles Y

Requires computer Y Y Y Y Y Y

NAVI- Navigation Assistance for Visually Impaired

TVS- Tactile Vision System

P1

50

44

System

s Lev

el Rev

iew