ACTIVE ANKLE FOOT ORTHOTIC
(AFO)
VOICE OF CUSTOMER
Design Project Management
Table of Contents
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Objective Tree
Needs Prioritization
Constraints
Functional Decomposition
Flow Diagram
Summary/Conclusions
Questions
Objective Tree
Objective Tree
Needs Prioritization
Customers ranked categories of objective tree for importance directly, group
members ranked every objective and category rankings were calculated:
Customer Rank

Safe 26%

Group rank
Perform on Flat Terrain 18.6%

Perform on Flat Terrain 21%

Perform on Special Terrain 17.3%

Portable 19%

Portable 16.4%

Comfortable 12%

Safe 16.2%

Durable 10%

Convenient 11.9%

Perform on Special Terrain 7%

Comfortable 10.3%

Convenient 5%

Durable 9.3%
Constraints







Low Weight (of AFO)
High Comfort
Easy patient interface with sensing system
Waterproof
Fits into normal shoe size
Safe
Method of Actuation?
Functional Decomposition
Determine Ideal State
Identifies
phase of
gait
Determin
es foot
position
Senses
Terrain
Utilizes
terrain
sensing
system
Interprets
sensor
data
Utilizes
terrain
sensing
system
Identifies
phase of
gait
Applys force
to foot
Removable
Allows
plantar
flexion
and
dorsiiflexion
Accomodates Range
of Users
Easily Adjustable
Determine Current
State
Support
Portability
Safely Regulate
Energy
Controls Foot
Position
Compares current and ideal states
Allows
adequate
motion
Safely store
Energy
Modifies Foot Behavoir
Safely Receive
Energy
The active ankle foot orthotic must mitigate the effects of foot drop.
Reduce/
eliminate
custom
fitting
process
Flow Diagram
The active ankle foot orthotic must mitigate the effects of foot drop.
Record
Data
ON/OFF
Micro-Controller
Terrain
Type
Determine
Actual State
Phase of
Gait
Determine
Ideal State
Compare
Real and
Ideal States
Check for
Errors
Identify
Action
Monitor
System
Status
Actuate
Device
Apply Force
or Allow
Movement
Health of
System
Monitor Energy
Level
Power
Receive
Power
Store
Energy
Regulate
Power
Waste Energy
(Noise, Heat,
Vibration, etc)
Summary/Conclusions


Stakeholders need a convenient active ankle foot
orthotic to mitigate the effect of foot drop while not
constraining user’s motion in ways that force
unnatural gait.
Moving forward it is likely that the scope will be
limited to:
 An
untethered active AFO using an actuation source
other than air muscles
 A tethered rehabilitation active AFO using air muscles
Questions?