1. Feet For All
TruBalance
Kevin Fontenot, Hayden Slack, Charles
Sprague, Vlad Voziyanov
2. Summary
• Background
• Specifications
• Alternative Solutions
• Methods
• Preliminary Results
• Specific Aims
• Research Plan
3. Background (Problem &
Need)
• 3 to 11 million amputees globally (LIMBS
International)
• Poor medical conditions, natural disasters, and war
• Less than 5% of patients in need receive care
(Walsh & Walsh, 2003)
• Poor conditions and lack of technological
investment (Ditterber, 2007)
5. Background (Problem to
be Solved)
• Multi-ankle and foot system
• Decrease cost
• Accessible materials
• Decrease manufacturing time
6. Specifications
Product Specifications
1. Multi-Axis
Design Specifications
1.1 Plantar and dorsiflexion plane of
motion
1.2 Inversion and eversion plane of motion
2. Weight 2.1 Device weighs less than 2 lbs
3. Length 3.1 Device is the same length as the
existing
foot
4. Foot Clearance 4.1 Foot is 3 3/8” – 3 1/2” high
5. Manufacturing Time 5.1 Part fabrication is less than 5 hours
5.2 Device assembly is less than 30
minutes
6. Supports User 6.1 Device supports users 50 – 100 lbs
7. Plantar and Dorsiflexion Range of 7.1 Plantar flexion 20 – 30 degrees
Motion 7.2 Dorsiflexion 0 – 10 degrees
8. Inversion and Eversion Range of 8.1 Inversion 35 – 45 degrees
Motion at 8.2 Eversion 15 – 25 degrees
Tarsal Joints
9. Inversion and Eversion Range of 9.1 Inversion 5 – 20 degrees
Motion at 9.2 Eversion 5 – 15 degrees
Subtalar Joint
10. Bolts, Washers, and Nuts 10.1 Aluminum 2024-T3
10.2 Stainless Steel 17-4, 303, 316, 440, 445
11. Ankle Body 11.1 Plastic (High Density Polyethylene,
Delrin, High Molecular Weight
Density
Polyethylene)
12. Foot 12.1 Niagara Foot
13. Cost of Prototype 13.1 $85 ± $15
14. Reliability 14.1 Device exceeds a 4500 N load in static
testing
15. Aesthetics 15.1 Resembles a physiological foot
16. Repair 16.1 Repaired on site
17. Operating Environment 17.1 Indoors, outdoors, moist, muddy,
water,
rocks, and trees
18. Operating Temperature 18.1 -50 – 124 degrees farenheit
19. Footwear 19.1 Shoes and sandals can be placed on
foot
20. Ankle Adaptability 20.1 Ankle attached to current foot
solutions
21. Bushing 21.1 Made from rubber
7. Alternative Solutions
(Feet)
Design Pros Cons
Niagara Foot - Hot, damp climates - Costly
- Energy storage - Complex shape
- Light weight - Permanent heel
deformation
Jaipur Foot - Light Weight - Heavy
- Inexpensive - Lacks toe support
- Bare foot walking - Deterioration
SACH Foot - Simple construction - Deteriorates with
- No moving parts moisture
- Inexpensive - Requires shoe for
protection
- Long fit time
Flex Foot - High activity - Costly
- Many Environments - Does not resemble
- Light Weight physiological foot
- Intended for running
8. Alternative Solutions
(Ankles)
Design Pros Cons
Proteor 1D111 - Uneven terrain - Single Axis
- Adjustable - Material
- Any SACH foot - Machinability
BiOm - Uneven terrain - Costly
- Multi-axis - Advanced Electronics
- Responsive - Not suitable for
outdoors
Seattle Systems - Adjustable - Single Axis
- Any single bolt foot - Material
- Uneven terrain - Machinability
9. Methods (Overview)
• Research
• Digital prototyping
• Three dimensional prototyping
• Design 1.03
14. Preliminary Results
• FEA 220 lbf
• Red areas are high
stresses
• Blue areas are low
stresses
• Natural Rubber
• The component is
feasible
15. Specific Aims
• 1) Confirm the selected materials are suitable
for use in low-income countries.
a) The materials will be low cost and attainable.
• 2) Design an ankle that functions multi-axially.
a) The ankle will produce motions similar to plantar and
dorsiflexion as well as inversion and eversion.
• 3) Develop a procedure that optimizes
manufacturing time.
a) The procedure will minimize manufacturing time for a
person with little manufacturing experience.
• 4) Select a foot that optimizes the function of
the multi-axis ankle and foot system.
a) The system will exhibit an approximate normal gait.
16. Research Plan
• Design
• Method of construction
• Quantitative Analysis
• Statistical analysis
• Division of labor
• Tentative work plan
• Cost analysis
18. Method of Construction
• High Density Polyethylene, M10-Titanium bolt,
polyurethane bushing
• Drill press, saw, wrenches, and other basic tools
• Manufactured in the Biomedical Engineering
Prototyping Lab
19. Quantitative Analysis
• Static testing according to Table 11 ISO 10328
• Measure the angle of inversion, eversion, plantar
flexion, and dorsiflexion
• Gait analysis
20. Statistical Analysis
• Range of motion testing
• The failure rate of materials
• The failure rate of existing devices
21. Division of Labor
Member Tasks
Kevin Fontenot -Digital prototyping
-Scheduling
-FEA
-Functional Prototyping
-Presentation organization
-Device improvement
Hayden Slack -Function prototyping
-Presentation organization
-ROM testing and analysis
Charles Sprague -Recording data
-Optimization
-Functional prototyping
-Presentation organization
Vlad Voziyanov -FEA
-Functional prototyping
-Presentation organization
-ISO 10328 Static testing and
analysis
22. Tentative Work Plan
Specific September October November December January February March April May
Aim
Research
Digital
Prototype
Manufacturing
Process
Functional
Prototype
ROM Testing
Gait Testing
Device
Optimization
Second
Functional
Prototype
ROM Testing
Gait Testing
Analysis of
Results
Suggested
Improvements
Final
Presentation
23. Component
Cost EstimateUnit Price ($) Units Used Cost ($)
Niagara Foot 25 1 25
Pylon 16.95 1 16.95
Pyramid
Receiver 21.9 1 21.9
Pyramid
Adapter 17.95 1 17.95
M10-Titanium
Bolt/140 9.77 1 9.77
6" Polyurethane
Rod 14.48 1 14.48
12"x12"x3" HDPE Sheet 122.82 2 245.64
Travel to Shriner's (Shreveport, LA) 25 3 75
Travel to Snell's
(Shreveport, LA) 25 2 50
Travel to VA
(Alexandria, LA) 40 1 40
Travel to
Methodist
Rehabilitation
(Monroe, LA) 15 2 30
Travel to LSUS
(Shreveport, LA) 25 2 50
Total ($) = 596.69
