Unifying Runtime Adaptation and Design Evolution

This paper describes human application of their knowledge and technological ability to fly and continue to enhance that power. Through application of their knowledge and technological ability, human beings have evolved the ability to fly and continue to enhance that power. Aircraft technology evolution is about the evolving design of the human movement on the Earth’s surface: people, goods, materials, and everything else. As the whole vehicle or animal evolves toward becoming better at moving mass on the landscape, the organs remain imperfect, because each represents a compromise. The whole vehicle or animal is a construct of organs that are ‘imperfect’ only when examined in isolation. The vehicle design evolves over time and becomes a better construct for moving the vehicle mass on the world map. Flow architectures are evolving right now, throughout nature and in technologies. The legacy of all flow systems (animate and inanimate) is: they have moved weight horizontally and improved the efficiency of that movement because of design evolution.

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Stakeholder-Driven Design Evolution of the Leveraged Freedom Chair Developing World Wheelchair

Volume 5: Education and Globalization; General Topics ◽

10.1115/imece2012-88881 ◽

2012 ◽

Cited By ~ 2

Author(s):

Amos G. Winter ◽

Mario A. Bollini ◽

Benjamin M. Judge ◽

Natasha K. Scolnik ◽

Harrison F. O’Hanley ◽

...

Keyword(s):

Developing Countries ◽

Angular Velocity ◽

East Africa ◽

Survey Data ◽

Angular Displacement ◽

Low Cost ◽

Center Of Gravity ◽

Mechanical Advantage ◽

Design Evolution ◽

Propulsion Force

The Leveraged Freedom Chair (LFC) is a low-cost, all-terrain, variable mechanical advantage, lever-propelled wheelchair designed for use in developing countries. The user effectively changes gear by shifting his hands along the levers; grasping near the ends increases torque delivered to the drive-train, while grasping near the pivots enables a larger angular displacement with every stroke, which increases angular velocity in the drivetrain and makes the chair go faster. This paper chronicles the design evolution of the LFC through three user trials in East Africa, Guatemala, and India. Feedback from test subjects was used to refine the chair between trials, resulting in a device 9.1 kg (20 lbs) lighter, 8.9 cm (3.5 in) narrower, and with a center of gravity 12.7 cm (5 in) lower than the first iteration. Survey data substantiated increases in performance after successive iterations. Quantitative biomechanical performance data were also measured during the Guatemala and India trials, which showed the LFC to be 76 percent faster and 41 percent more efficient during a common daily commute and able to produce 51 percent higher peak propulsion force compared to conventional, pushrim-propelled wheelchairs.

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