Active Ankle Foot Orthotic (AFO) Voice of the Engineer
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Transcript of Active Ankle Foot Orthotic (AFO) Voice of the Engineer
ACTIVE ANKLE FOOT ORTHOTIC(AFO)
VOICE OF THE ENGINEER
Design Project Management
Introduction to the Team
Shane Reardon - (ME) Travis Blais - (ME)Diane Kang - (IE)Austin Frazer – (ME)
Gerald GaravusoTeam Members Mentor
StakeholdersDr. Lamkin-KennardDr. DeBartoloChristopher Sullivan
Table of Contents• Functional Decomposition• Benchmarks• Specifications• House of Quality• Family Roadmap• Potential Concepts• Staffing• Feedback
Overview Lay out roadmap for air muscle-driven
active Ankle-Foot Orthotic Eliminate the condition known as “foot
drop”
Midstance Foot Drop (Between Propulsive and Contact Phase)
Functional Decomposition
Functional Decomposition Cont.
The active ankle foot orthotic must mitigate the effects of foot drop.
Allows adequat
e motion
Modifies Foot Behavoir
Interprets
sensor data
Allows plantar flexion
and dorsiifle-xion
Identifies
phase of gaitUtilize
s terrain sensin
g syste
m
Compares current and ideal states
Determines foot
position
Senses
TerrainUtilize
s terrain sensin
g syste
m
Identifies
phase of gait
Controls Foot
Position
Applies force to
foot
Support Portability
Safe
ly st
ore
Ener
gySa
fely
Re
ceiv
e En
ergy
Safe
ly
Regu
late
En
ergy
Accomodates Range of Users
Easil
y Ad
just
able
Reduce/
eliminate
custom
fitting proces
s
Rem
ovab
le
Determine Current State
Determine Ideal State
NAMEPortable Powered
AFORichie Dynamic
Assist BraceFillauer Dynamic
WalkOssur AFO Dynamic
Soft Pneumatic Exoskeleton
DIMENSIONS [Qualitative Size]
?35 mm Heel Cup. Orthotic Extends approx 8 inches up
calf
Length (230-270mm), width (67,5-88,5mm??), height
(320-370mm)
Foot plate: 8.75"-11", Calf Height: 12-15.75", Heel
height: 0.4"-0.6"
WEIGHT (kg) 3.1 "Lighter than most AFOs" Exact # not given
105-142 g 75-140 g 3
MAX APPLIED TORQUE (Nm)
9Nm at 90 psig assist ? ? ?
POWER SOURCE Carbon Dioxide bottle N/A N/A N/A Carbon Dioxide bottle
ADVANTAGES Offers a clinical tool in many areas of rehabilitation
Supports patients over 200 lbs. "Offers dynamic dorsiflexion assist".
Appears to fit inside normal
Very lightweight. Fits easily into regular shoes. High
strength
Fits into shoe very easily, very lightweight
soft material, easily adjustable, portable
DISADVANTAGES Only lasts 37 minutes and low assistive torque
Is not capable of variable force depending on the severity of the foot drop
issue. No terrain sensing.
Doesn't appear excessively supportive
finite usage time
ACTIVE ELEMENT Pneumatic Actuator 2 spring like hinges on either side of the orthotic
Semi-rigid material Semi-rigid material Air muscle
PERFORMANCE METRICS Range of motion, weight, size
Suggested weight range up to 265 lbs
EXPERIMENTAL EVALUATION
3 Non disabled walkers and 1 disabled walkers
This is commercially available
This is commercially available
This is commercially available
RANGE OF MOTION 15 degrees of dorsiflexion
Photo
Engineering Specification
Number
Engineering Specification Description
Units of Measure
Preferred Direction
Nominal Value
Method of Validation
Stems From Customer Need Notes
s1 Torque on Foot N-m Up ≥±1.5 Test FT1,2,4,ST1,5
s2 System response time (sensing terrain to actuating device) ms down <150 Test ST3
s10 allowable range of motion between foot and shin degrees range 94.5 to
137.7 Test FT1,3,CF8,9,ST1
s12 untethered usage time hrs/steps up >3000 steps P1,2,D1 project dependants14 fits calf (diameter) mm range 292 to 433 Measurement CF1,3,5 user dependents15 fits foot (length) mm range 212 to 317 Measurement CF1,3,5 user dependents17 force to secure constraints N down < 80 N Test C4 s18 force to remove constraints N down < 80 N Test C3 s24 weight of entire device kg down ≤2 or ≤3 weigh FT6 s31 Minimum life until failure steps up 5.5 million test D1 s32 Allowable toe extension/flexion degrees range 0-50 test CF8, CF9
Specifications
Engineering Specifications Spec s27 s31 s32 s33
Stakeholders need a convenient active ankle foot orthotic to mitigate the effects of foot drop while not constraining user's motion in ways that force unnatural
gait
Customer Weights
Has housing around
electronic
components
Minimum life until
failure
Allowable toe
extension/flexion
Fits with users
regular shoe size
VOC - Affinity Groups CO # VOC - Customer ObjectivesPreferred Direction
- up up -
Comfort
CF8 allow toes to flex up12.0%
9 CF9 keep toes from curling down 9
CF10 aesthetically pleasing CF11 low noise
Durability
D1 reliable for day to day usasge10.0%
9 9 D2 sensors/controls withstand elements 9 D3 usable in rain/shower 9 D4 washable 9
Convenient
C1 fit into normal shoe size
5.0%
9
C2 reduce time and cost of custom fitting process
C3 easy to take off C4 easy to put on C5 easy patient interface with sensing system C6 easily adjustable
House of Quality
Family Roadmap
Potential Concepts Ratchet and flexible air muscle pictures
Staffing
Feedback Family roadmap and individual project
definitions were all approved.
Dr. DeBartolo requested project submission into ASME summer bioengineering competition
Questions?