Variable Position Mid-Wheel Drive System for Power Wheelchairs

The three primary drive systems for power wheelchairs-front, middle and rear wheel drives-have a wide range of advantages and disadvantages. Users select the drive system based on their individual needs. Currently, no power wheelchair has a variable position drive system that the power wheelchair user can automatically move fore/aft through a range that will provide the benefits of rear, middle and front wheel drive configurations (approximately a 36 cm range). Such a system would allow users to receive all the benefits of each drive wheel configuration in a single wheelchair (for example, adjusting the drive wheels toward the rear for stability and speed outdoors, and toward the center for maneuverability indoors). In Phase I, Criterion Health, Inc. will design, construct, and evaluate a proof of concept model based on current mid wheel designs with, however, a variable position drive wheel system that can move. forward or backward from the mid wheel position using a simple mechanical system to change the position of the drive wheels. A series of five structured tests for maneuverability and/or stability will be used to compare performance as a function of placement of the drive wheels. Feasibility will be based on demonstrating that a variable position drive wheel system will optimize performance under a greater variety of terrain and environmental conditions than a single position drive wheel system. Phase I will focus on establishing the benefits of the variable position drive wheel system with the proof of concept model. Phase II will focus on the development of a power wheelchair base prototype with the variable position drive system, including any necessary enhancement and/or development of the control system. Phase II will also include the evaluation of the unit with human subjects, including, once safety has been demonstrated, power wheelchair users. The preparation and evaluation of a full working prototype will complete Phase II and precede Phase III commercialization in which it is anticipated that a major power wheelchair manufacturer will be interested in licensing the technology. The technology will provide power wheelchair users the ability to have a single wheelchair with the flexibility of use that is currently unavailable.