October 26, 2011 BME 401 Senior Design Mentor: Jack Engsberg, PhD

1. Flex2PlayAn ankle strengthening device with virtualreality interface for children with cerebral palsy October 26, 2011 • BME 401 Senior Design • Mentor: Jack Engsberg, PhD • Amanda Meppelink(Presenter), Kelly Hill, Liz Phillips

2. Overview ○ Alternatives○ Analysis of Designs ○ Chosen Design ○ Our Approach The Need • A strength training device that • is safe for in-home use • requires minimal setup or user training • is affordable • is portable • motivates patient participation

3. Overview ○ Alternatives○ Analysis of Designs ○ Chosen Design ○ Our Approach 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

4. Overview ○ Alternatives○ Analysis of Designs ○ Chosen Design ○ Our Approach 20° Dorsiflexion 0° Neutral –50° Plantarflexion Dorsiflexion τ=F*d*sin(θ) F=35Nm/(0.28m*sin(90)) F=125N Plantarflexion τ=F*d*sin(θ) F=101Nm/(0.28m*sin(90)) F=361N 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 • Available in at least 15% increments • Affordable – $200 target • Portable – 8 ft3 • Virtual Reality Interface • 2010 BME401 Group “Wii Controlled Gaming for Therapy”

5. Overview○ Alternatives○ Analysis of Designs ○ Chosen Design ○ Our Approach Alternatives

6. Overview○ Alternatives○ Analysis of Designs ○ Chosen Design ○ Our Approach Springs Left: Torsion Middle: Compression Right: Extension

7. Overview○ Alternatives○ Analysis of Designs ○ Chosen Design ○ Our Approach Pulleys • Use free weights to provide resistance • In plantarflexion, pulley used to alter direction of force

8. Overview○ Alternatives○ Analysis of Designs ○ Chosen Design ○ Our Approach Levers • Consist of fulcrum, load, and effort • Magnitude of effort based on distance from fulcrum

9. Overview○ Alternatives○ Analysis of Designs ○ Chosen Design ○ Our Approach Magnetism • Use permanent magnet, electromagnet, or combination of both

10. Overview○ Alternatives○ Analysis of Designs ○ Chosen Design ○ Our Approach Motors • AC Motor • Ideal for fixed speed applications • DC Brushed Motor • DC Brushless Motor • Speed controlled by adjusting amount of electrical current Side View Front View

11. Overview○ Alternatives○ Analysis of Designs ○ Chosen Design ○ Our Approach Elastic Bands • Elastic bands provide resistive force • tan = extra thin • yellow = thin • red = medium • blue = extra heavy • black = special heavy • silver = super heavy • gold = max

12. Overview ○ Alternatives○ Analysis of Designs ○ Chosen Design ○ Our Approach Criterion for Pugh Chart • Essential • Cost, Safety, Strength Range, Range of Motion, Ability to Interface with Wii • High Importance • Durability, Train Both PF and DF • Important • Size, Weight, Ease of Setup, Ease of Use • Other • Strength Resolution, Train with Knee Extended, Train More than One DOF

13. Overview ○ Alternatives○ Analysis of Designs ○ Chosen Design ○ Our Approach Pugh Chart

14. Overview ○ Alternatives○ Analysis of Designs ○ Chosen Design ○ Our Approach Springs Pugh Results • High score • Cost ($1-$24) • Safety • Strength Range • Low score • Strength Resolution • More than One Degree of Freedom

15. Overview ○ Alternatives○ Analysis of Designs ○ Chosen Design ○ Our Approach Motor Pugh Results • High Score • Strength Range • Range of Motion • Train Both PF and DF • Low Score • Very Expensive ($122-$966) • Safety • Durability

16. Overview ○ Alternatives○ Analysis of Designs ○ Chosen Design ○ Our Approach Chosen Design: Elastic Bands Left: Iso View Top Right: Top View Bottom Right: Back View

17. Overview ○ Alternatives○ Analysis of Designs ○ Chosen Design ○ Our Approach Flex2Play • Limitations • Does not reach maximum PF force value • Variability among patients

18. Overview ○ Alternatives○ Analysis of Designs ○ Chosen Design ○ Our Approach Design Schedule

19. Overview ○ Alternatives○ Analysis of Designs ○ Chosen Design ○ Our Approach Kelly – Analytical • Preliminary Presentation • Weekly Reports • Research on Alternative Ideas • DesignSafe Amanda – Driver • Progress Presentation • Schedule Manager • Research on Chosen Design • Meet weekly with mentor • Write and revise reports • Conduct background research • Provide feedback to group Liz – Expressive • Final Presentation • Web Designer • Research on Alternative Ideas Team Responsibilities

20. 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>. • DyneticSystems. (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>.

21. Flex2PlayAn ankle strengthening device with virtualreality interface for children with cerebral palsy October 26, 2011 • BME 401 Senior Design • Mentor: Jack Engsberg, PhD • Amanda Meppelink(Presenter), Kelly Hill, Liz Phillips