Design of a custom racing hand-cycle: review and analysis.

PURPOSE: This paper describes the design, manufacture and evaluation of a custom hand-cycle with a Delta-style frame and fork steering. The state of hand-cycle design and future design directions are also examined. METHOD: The design of the custom hand-cycle was based on these criteria: Light weight, aerodynamics, climbing ability, ergonomic fit and the user's specific needs. We designed and built a custom hand-cycle for one expert user, therefore, the user's personal needs were key design drivers. The hand-cycle was evaluated by the user over three years of use. RESULTS: During three years of evaluation and over 8000 km of use there were two frame failures: (i) A crack propagated around one of the tubes connecting the mainframe tube to the headset tube; and (ii) a crack propagated around the circumference of the curved part of the main frame tube directly behind the seat. The first failure was repaired and after the second, the device was retired. The evaluation of this design serves as a basis for a new set of design criteria. CONCLUSIONS: Large amounts of frame flexion can indicate eventual plastic deformation and failure. Future hand-cycle designs should see the use of more advanced materials, finite element analysis software, and continued incorporation of bicycle technology and design innovation.

Evaluation of pushrim-activated power-assisted wheelchairs using ANSI/RESNA standards.

OBJECTIVE: To determine and compare performance of pushrim-activated power-assisted wheelchairs (PAPAW) (iGLIDE, e-motion, Xtender) on national standards. DESIGN: Engineering performance and safety evaluation. SETTING: A Veteran Affairs and university-based research center. SPECIMENS: Nine PAPAWs. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Static, dynamic stability, brake effectiveness, maximum speed, acceleration, retardation, energy consumption, static, impact, and fatigue strength. RESULTS: There was no significant difference among the 3 models in forward stability. The iGLIDE was the most stable, whereas the e-motion was the least stable model in the rearward stability tests. All PAPAWs performed equally on the slopes of 3 degrees and 6 degrees in the forward and rearward directions. Braking distance was the highest for e-motion (5.64+/-0.28m) and the lowest (1.13+/-0.03m) for the iGLIDE in forward direction. The average equivalent cycles of all PAPAWs were 318,292+/-112,776.6 cycles (n=8) on the fatigue tests. All PAPAWs passed the impact and static strength tests. CONCLUSIONS: The standards of the American National Standards Institute and the Rehabilitation Engineering and Assistive Technology Society of North America could act as quality assurance tool for wheelchairs. The standards for wheelchairs were first approved in 1990; after 17 years, exceeding the minimum values in the standards would be a reasonable expectation.

Participatory design in the development of the wheelchair convoy system.

BACKGROUND: In long-term care environments, residents who have severe mobility deficits are typically transported by having another person push the individual in a manual wheelchair. This practice is inefficient and encourages staff to hurry to complete the process, thereby setting the stage for unsafe practices. Furthermore, the time involved in assembling multiple individuals with disabilities often deters their participation in group activities. METHODS: The Wheelchair Convoy System (WCS) is being developed to allow a single caregiver to move multiple individuals without removing them from their wheelchairs. The WCS will consist of a processor, and a flexible cord linking each wheelchair to the wheelchair in front of it. A Participatory Design approach - in which several iterations of design, fabrication and evaluation are used to elicit feedback from users - was used. RESULTS: An iterative cycle of development and evaluation was followed through five prototypes of the device. The third and fourth prototypes were evaluated in unmanned field trials at J. Iverson Riddle Development Center. The prototypes were used to form a convoy of three wheelchairs that successfully completed a series of navigation tasks. CONCLUSION: A Participatory Design approach to the project allowed the design of the WCS to quickly evolve towards a viable solution. The design that emerged by the end of the fifth development cycle bore little resemblance to the initial design, but successfully met the project's design criteria. Additional development and testing is planned to further refine the system.

The development and preliminary evaluation of a training device for wheelchair users: the GAME(Wheels) system.

PURPOSE: Training of appropriate wheelchair propulsion methods may be beneficial to the individual who uses a wheelchair by reducing the incidence of pain and improving one's quality of life. This paper discusses the development and initial testing of a training device that was developed to aid in wheelchair propulsion techniques: GAME(Wheels) System. METHODS: Two separate models of GAME(Wheels) have been developed: a GAME(Wheels) Clinical and a GAME(Wheels) Trainer. Details of the development process and the refinement have been included in this manuscript. To verify and compare the practicality and functionality of the two GAME(Wheels) systems, several focus groups were conducted: first to determine whether the systems could be set-up with informational materials and second to determine if the systems could be taught to novice users. RESULTS: Results from the focus group indicate that the overall impressions of the systems were that they were 'fun' to play. Suggestions were raised to improve the design, which have been incorporated into further refinement of the GAME systems. CONCLUSIONS: This paper provides an overview of the development of a wheelchair-training device. Valuable information was gained to improve the design of the GAME(Wheels) systems.