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

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 ft 3  Virtual Reality Interface 2010 BME401 Group “Wii Controlled Gaming for Therapy” Overview ○ Alternatives○ Analysis of Designs ○ Chosen Design ○ Our Approach 20° Dorsiflexion 0° Neutral –50° Plantarflexion Plantarflexion τ=F*d*sin(θ) F=101Nm/(0.28m*sin(90)) F=361N Dorsiflexion τ=F*d*sin(θ) F=35Nm/(0.28m*sin(90)) F=125N

Alternatives Mechanism of Resistance SpringsGravitationalMagnetismMotorsElastic Overview ○ Alternatives○ Analysis of Designs ○ Chosen Design ○ Our Approach

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

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

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

Magnetism  Use permanent magnet, electromagnet, or combination of both 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 Overview ○ Alternatives○ Analysis of Designs ○ Chosen Design ○ Our Approach Side View Front View

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

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

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

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

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

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

Works Cited  Aisen, ML, et al. "Cerebral Palsy: Clinical Care and Neurological Rehabilitation." Lancet Neurology 10.9 (2011):  Boley, B. L. (1997). Overview of Motor Types Tutorial. Retrieved October 23, 2011, from  Compression Springs. 23 October  Dynetic Systems. (n.d.). Brushless vs Brushed. Retrieved October 23, 2011, from Dynetic Systems:  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):  Simple Machine Elements. 23 October  The Hygenic Corporation. (2006). Resistance Band & Tubing Instruction Manual. Akron, OH, USA.  Torsion Springs. 23 October