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?