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UBC Theses and Dissertations

Personal autonomy and wheeled mobility assistive device use : user-driven research and development of advanced technologies Khalili, Mahsa


About 1% of Canadians and 2.3% of Americans rely on wheeled mobility assistive devices (WMADs), such as manual wheelchairs (MWCs) or power wheelchairs (PWCs), to perform activities of daily living. Recently, several power-assist add-ons have been developed that can be attached to MWCs and provide extra power assistance based on user demand. We conducted an online survey to evaluate the perceived autonomy of WMAD users in different contexts. The findings of our survey (N = 123) showed that users of MWCs with add-ons had higher satisfaction with their autonomy across different environments. We performed interviews with MWC users (N = 16) to gather their views about the design and characteristics of different wheelchair add-ons (i.e., powered wheels, front-end and rear-end attachments). Participants noted that pushrim-activated power-assisted wheels (PAPAWs) are intuitive to use and have the potential to enhance autonomy by enabling access to different environments and improving health conditions. However, participants identified some limitations of existing PAPAWs (e.g., safety and controllability) that affect PAPAWs’ usability. To address some of the identified limitations of PAPAWs, we developed (1) a personalized adaptive PAPAW controller that incorporates the user’s input in the decision making algorithm and enables users to perform their desired activities by providing appropriate assistance; and (2) an adaptive control strategy that responds effectively to changes in the environmental conditions (e.g., type of surface). We found that the propulsion effort was significantly reduced when using the adaptive PAPAW controllers compared to a conventional PAPAW controller. Taking into account the advantages provided by adaptive PAPAWs, we believe that the adoption of the proposed personalized and terrain-based controllers has the potential to enhance the perceived sense of personal autonomy among WMAD users (e.g., by improving health conditions and accessibility of outdoor terrains). Further investigations are required to gather data from a larger group of skilled wheelchair users to evaluate the reliability and efficacy of using developed PAPAWs in this research.

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