FLEX2PLAYAn ankle strengthening device with virtual

reality interface for children with cerebral palsy

Group 21December 7, 2011

BME 401 Senior DesignMentor: Jack Engsberg, PhD

Liz Phillips (Presenter), Kelly Hill, Amanda Meppelink

Outline

Overview Details of Chosen Design Materials and Manufacturing Conclusion

The Need A strength training

device thatis safe for in-home

userequires minimal

setup or user training

is affordableis portablemotivates patient

participation

Overview ○ Details of Chosen Design ○ Materials & Manufacturing ○ Conclusion

The Scope

To design an at-home ankle strengthening device – Flex2Play – that motivates participation by interfacing therapy with a WiiMote which controls online video games

Overview ○ Details of Chosen Design ○ Materials & Manufacturing ○ Conclusion

Design Specifications Full range of motion

30° from neutral in DF -50° from neutral in PF

Progressive Resistance 35 Nm DF torque 101 Nm PF torque Resistance in at least 15%

increments Affordable – $200 target Portable – 30lbs 8 ft3

Virtual Reality Interface 2010 BME401 Group “Wii

Controlled Gaming for Therapy”

20° Dorsiflexion

0° Neutral

–50° Plantarflexion

Plantarflexionτ=F*d*sin(θ)F=101Nm/(0.28m*sin(90))F=361N

Dorsiflexionτ=F*d*sin(θ)F=35Nm/(0.28m*sin(90))F=125N

Overview ○ Details of Chosen Design ○ Materials & Manufacturing ○ Conclusion

Chosen Design: Elastic Bands

Overview ○ Details of Chosen Design ○ Materials & Manufacturing ○ Conclusion

Four Main Components: Footplate Base Hinge Joint Elastic Bands

FootplateOverview ○ Details of Chosen Design ○ Materials & Manufacturing ○ Conclusion

Exploded Isometric View

WiiMote Controller Connection

Overview ○ Details of Chosen Design ○ Materials & Manufacturing ○ Conclusion

Isometric View

Side View

BaseOverview ○ Details of Chosen Design ○ Materials & Manufacturing ○ Conclusion

Isometric View

Overview ○ Details of Chosen Design ○ Materials & Manufacturing ○ Conclusion

Hinge JointOverview ○ Details of Chosen Design ○ Materials & Manufacturing ○ Conclusion

Isometric View

Exploded Front View

Elastic Band Connections

Overview ○ Details of Chosen Design ○ Materials & Manufacturing ○ Conclusion

Elastic Band Connection Calculations

Overview ○ Details of Chosen Design ○ Materials & Manufacturing ○ Conclusion

Manufacturing

Overview ○ Details of Chosen Design ○ Materials & Manufacturing ○ Conclusion

Estimated Flex2Play market size 114,000 children in US age 5-18 with spastic

cerebral palsy

Commercial Production Expected 1,000 units sold in the first year Expected 4,000 units sold in next 5 years

Near Future One Flex2Play prototype for device evaluation 10 devices for evaluation in small sample

MaterialsComponent Products Cost for 1 deviceFootplate footplate (1), side plates (2), washers (4),

screws (4), nuts (4), straps (2)$65.09

Base telescoping post (1), base post (1), pin (1), base plate (1), stabilizing posts (2), rubber, connection hoop, adhesive

$165.70

Hinge hinge plate (1), bushing (4), axle (1), bolt (2), set screw (2), washer (2), Velcro

$83.90

1 device 10 devices

Mass production

Materials Costs $314.66 $156.58 $39.00Manufacturing Costs

$225.00 $225.00 $150.00

Total $539.66 $381.58 $189.00

Overview ○ Details of Chosen Design ○ Materials & Manufacturing ○ Conclusion

ConclusionsOverview ○ Details of Chosen Design ○ Materials & Manufacturing ○ Conclusion

Specification FulfillmentAffordable – $189 mass productionPortable – 8.82 lbs and 2 ft3

Safety Considerations Future directions

Intellectual PropertyPilot Study with 10 devices

ReflectionsWhat we learnedWhat we would do differently

Works Cited Aisen, ML, et al. "Cerebral Palsy: Clinical Care and Neurological

Rehabilitation." Lancet Neurology 10.9 (2011): 844-52. Boley, B. L. (1997). Overview of Motor Types Tutorial. Retrieved October 23,

2011, from http://www.oddparts.com/acsi/motortut.htm Compression Springs. 23 October 2011.

<http://www.leespring.com/int_learn_compression.asp>. Dynetic Systems. (n.d.). Brushless vs Brushed. Retrieved October 23, 2011,

from Dynetic Systems: http://www.dynetic.com/brushless%20vs%20brushed.htm

Pinneger, Gavin J and Andrew G. Cresswell. "Residual force enhancement after lengthening is present during submaximal plantar flexion and dorsiflexion actions in humans." Journal of Applied Physiology (2006): 18-25.

Simple Machine Elements. 23 October 2011. <http://cnx.org/content/m13594/latest/>.

The Hygenic Corporation. (2006). Resistance Band & Tubing Instruction Manual. Akron, OH, USA.

Torsion Springs. 23 October 2011. <http://www.leespring.com/int_learn_torsion.asp>.

FLEX2PLAYAn ankle strengthening device with virtual

reality interface for children with cerebral palsy

October 26, 2011BME 401 Senior Design

Mentor: Jack Engsberg, PhDAmanda Meppelink(Presenter), Kelly Hill, Liz Phillips

Elastic Bands

Overview ○ Details of Chosen Design ○ Materials & Manufacturing ○ Safety○ Conclusion