Electric Powered Wheelchairs (EPWs) are key assistive devices for Veterans with Disabilities (VwD), providing mobility and independence. However, existing EPWs are not intended for heavy duty use in outdoor environments and have difficulties navigating steep hills, cross slopes, and other uneven surfaces commonly encountered in outdoor environments. The limitation of the EPW technology in such environments can cause loss of stability and traction, leading to tips and falls. Approximately 100,000 wheelchair-related injuries, mostly associated with falls, are treated in emergency departments every year. Moreover, 65%-80% of these injuries, are caused by tips and falls. Our previous research introduced a Mobility Enhancement Robot (MEBot) EPW to enhance the mobility and safety of VwD when driving in outdoor environments. MEBot provides a self-leveling application that maintains the VwD's center of mass within its footprint to prevent tips and falls in these environments. In preliminary usability studies with active EPW users using MEBot, participants agreed to feel stable with MEBot and stated the importance of the MEBot self-Leveling Application (MEBot-SLA) when driving on steep ramps and curb-ramps. Also, EPW users suggested to (1) self-adjust in real-time, (2) avoid unnecessary seat adjustments, and (3) provide continuous operation of the self-leveling application. Therefore, the objectives of this research were to (Aim 1) perform engineering design upgrades in MEBot-SLA to address EPW user's feedback and (Aim 2) to perform a user evaluation of the optimized MEBot-SLA.
Aim 1 of this work proposes to (1) Incorporate electro- hydraulic actuators and force sensors to perform rapid seat adjustment for the user's safety and comfort (2) redesign electronics to operate electro-hydraulic actuators and sensors, (3) implement the MEBot-SLA control algorithm to reduce power consumption and unwanted seat adjustment, and (4) perform static and dynamic stability analyses to evaluate the accuracy and feasibility of the optimized MEBot-SLA.
Aim 2 proposes to evaluate MEBot-SLA in comparison with the prior MEBot-SLA and VwD' own EPWs in outdoor driving tasks. We hypothesize that VwD will report (Hypothesis 2a) significantly better driving performance in terms of safety (less change in seat angle) and efficacy (similar or higher number of completed tasks and less seat angle adjustment time), and (Hypothesis 2b) higher satisfaction (higher scores in satisfaction (QUEST) and usability (SUS) assessment tool) when using MEBot-SLA in comparison to the prior MEBot-SLA and their own EPWs on driving tasks that simulate outdoor environments. We will recruit up to 10 active VwD who own EPWs. Participants will be trained in the use of MEBot- SLA to reduce selection bias. After training, each participant will complete five trials using the three devices on three outdoor driving tasks. Quantitative driving metrics will be recorded for each trial and EPW using a data acquisition board. At the end of the study, participants will complete the QUEST and SUS questionnaire for each EPW. Our findings will demonstrate the use of a novel robotic EPW to enhance safety and mobility in outdoor environments, evidence of EPW mobility limitations in common environments, and a research platform for continuous improvement of the EPW driving performance. If successful, the results will provide evidence for a larger scale study in in-home trials to prevent tips and falls of VwD who use EPWs in real- world environments
At present, Power wheelchairs are one of the most important mobility technologies available for Veterans with disabilities (VwD). The VA supplies over 80,000 new wheelchairs annually at a 5.2% annual growth rate. However, matching a Veteran to an inappropriate or low-quality wheelchair may result in injuries/accidents due to tips and falls when driving in common environments, particularly curb-ramps, uneven surfaces, and outdoor terrains. In some cases, these accidents lead to hospitalization. Two major adverse consequences of these accidents are lower community participation and abandonment of their wheelchairs. The goal of this CDA- 1 project is the optimization of a novel robotic wheelchair to prevent tip/falls in common environments. The results of this study will provide evidence to enhance the safety and mobility of VwD when using MEBot and a research platform to improve mobility assistive technology.
