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 Garavuso

Team Members Mentor

Stakeholders

Dr. 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 s

tore

Energ

y

Safe

ly

Rece

ive

Energ

yS

afe

ly

Reg

ula

te

Energ

y

Accomodates Range of Users

Easi

ly

Adju

stable

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 given105-142 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

ADVANTAGESOffers 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

DISADVANTAGESOnly 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 Actuator2 spring like hinges on

either side of the orthoticSemi-rigid material Semi-rigid material Air muscle

PERFORMANCE METRICSRange of motion, weight,

sizeSuggested 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  

s2System response time (sensing

terrain to actuating device)ms down <150 Test ST3  

s10allowable range of motion

between foot and shindegrees 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 dependant

s14 fits calf (diameter) mm range 292 to 433 Measurement CF1,3,5 user dependent

s15 fits foot (length) mm range 212 to 317 Measurement CF1,3,5 user dependent

s17 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 up

12.0%

    9  CF9 keep toes from curling down     9  

CF10 aesthetically pleasing        CF11 low noise        

Durability

D1 reliable for day to day usasge

10.0%

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

C2reduce 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?