Adequacy of power wheelchair control interfaces for persons with severe disabilities: a clinical survey.

The extreme difficulty with which persons with severe disabilities have been taught to maneuver a power wheelchair has been described in case studies, and anecdotal evidence suggests the existence of a patient population for whom mobility is severely limited if not impossible given currently available power wheelchair control interfaces. Since our review of the literature provided little evidence either in support or refutation of the adequacy of existing power wheelchair control interfaces, we surveyed 200 practicing clinicians, asking them to provide information about their patients and to give their impressions of the potential usefulness of a new power wheelchair navigation technology. Significant survey results were: Clinicians indicated that 9 to 10 percent of patients who receive power wheelchair training find it extremely difficult or impossible to use the wheelchair for activities of daily living. When asked specifically about steering and maneuvering tasks, the percentage of patients reported to find these difficult or impossible jumped to 40. Eighty-five percent of responding clinicians reported seeing some number of patients each year who cannot use a power wheelchair because they lack the requisite motor skills, strength, or visual acuity. Of these clinicians, 32 percent (27 percent of all respondents) reported seeing at least as many patients who cannot use a power wheelchair as who can. Nearly half of patients unable to control a power wheelchair by conventional methods would benefit from an automated navigation system, according to the clinicians who treat them. We believe these results indicate a need, not for more innovation in steering interfaces, but for entirely new technologies for supervised autonomous navigation.

Initial results in the development of a guidance system for a powered wheelchair.

This paper describes the development of an automatically guided powered wheelchair for individuals with severe disabilities. The navigation and control of the wheelchair is based the accurate estimation of the location of the wheelchair within its operating workspace. A novel method used to generate and track reference paths which take the user to and from various destinations within the wheelchair's environment is presented. The paper also provides a qualitative description of the restrictions and requirements that are specific to the wheelchair application as well as the way in which the current system addresses these restrictions and requirements. Finally, actual experimental runs of the wheelchair system are presented.