Kinematics and Stability Analysis of a Novel Power Wheelchair When Traversing Architectural Barriers

Perception of autonomy among people who use wheeled mobility assistive devices: dependence on environment and contextual factors

PURPOSE

To evaluate and compare the perceived autonomy of people using wheeled mobility assistive devices (WMADs) in five community-based environments. To evaluate how personal, environmental, and assistive device-related factors impact the perceived autonomy of WMAD users.

METHOD

A study-specific questionnaire was used to evaluate perceived satisfaction of WMAD users with their autonomy in five environments: the Home Environment, Buildings Outside of the Home Environment, Outdoor Built Environment, Outdoor Natural Environment, and Transportation. For each environment, participants rated their satisfaction with autonomy about 15 personal, environmental, and assistive device-related factors. Qualitative perceptions were also collected with open-ended questions.

RESULTS

Participants included 123 full- and part-time community-dwelling WMAD users. Participants' overall satisfaction with autonomy in the Outdoor Natural Environment was statistically significantly lower compared to the other four environments (p < 0.05). In all environments, the top factor respondents were most satisfied with was WMAD ease of use. Their least satisfaction was when negotiating stairs, curbs, or obstacles in the Home, Buildings Outside of the Home, and the Outdoor Built Environments. In the Outdoor Natural Environment, the most dissatisfaction was with manoeuvring on different terrains. Responses to open-ended questions supported the quantitative findings and highlighted the effects of various factors on autonomy (e.g., subject-environment familiarity).

CONCLUSIONS

WMAD users reported the greatest restriction to their autonomy in outdoor environments. Different context-specific factors were found to impact autonomy in different environments. Understanding how environment-specific contextual factors contribute to overall perception of autonomy may inform the development of future strategies to overcome identified limitations and challenges.Implications for RehabilitationWheeled mobility assistive device (WMAD) users experienced the highest autonomy in their home environments, specifically, when having access to home modification services.WMAD users had the lowest autonomy in the outdoor natural environment, with manoeuvrability on different terrains being the main predictor of the overall satisfaction with autonomy in this environment.Environment-specific contextual factors with significant impacts on perceived autonomy were identified that can inform the design and development of future WMADs (e.g., distance travelled, safety).

Wheelchair users' perceptions of a system enabling them to traverse rough terrain controlling their own wheelchair

We recently developed a dynamic mimicking system that mounts a user's wheelchair onto a carrier platform capable of performing required manoeuvres using the wheelchair's own controls. Two wheelchair user studies were performed to evaluate users' perception of their own wheelchair and the proposed system. The first user study included ten wheelchair users who were interviewed in order to map their current perceptions toward their wheelchair and their views about its shortcomings when traversing rough terrains. In the second study, the system was explained to 33 participants who were then exposed to three simulations of its main features. Participants were interviewed and the experimenter wrote down their answers, which were analysed using IBM SPSS Statistics 27 software. The conclusions are that special consideration should be given to motorized wheelchair users, and that the designers of the system should include a user interface that explains and demonstrates the system to users.

Mini-review: Robotic wheelchair taxonomy and readiness

Robotic wheelchair research and development is a growing sector. This article introduces a robotic wheelchair taxonomy, and a readiness model supported by a mini-review. The taxonomy is constructed by power wheelchair and, mobile robot standards, the ICF and, PHAATE models. The mini-review of 2797 articles spanning 7 databases produced 205 articles and 4 review articles that matched inclusion/exclusion criteria. The review and analysis illuminate how innovations in robotic wheelchair research progressed and have been slow to translate into the marketplace.

Curb Negotiation With Dynamic Human-Robotic Wheelchair Collaboration

Wheelchair users often face architectural barriers such as curbs, limiting their accessibility, mobility, and participation in their communities. The mobility enhancement robotic (MEBot) wheelchair was developed to navigate over such architectural barriers. Its application allows wheelchair users to negotiate curbs automatically while the user remains in control. The application was optimized from a manual to a semiautomated process based on wheelchair users' feedback. The optimized application was evaluated by experienced wheelchair users who navigated over curbs of different heights. Participants evaluated MEBot in terms of effectiveness, workload demand, and usability. Ten participants successfully ascended and descended curbs of different heights at an average completion time of 55.7 ± 19.5 and 30.3 ± 9.1 s, respectively. MEBot maintained stability during the process, while participants reported low levels of effort, frustration, and overall cognitive demand to operate MEBot. Furthermore, participants were satisfied with the ease of learning and using the MEBot curb negotiation application to overcome the curbs but suggested less wheel adjustment for comfort and a faster pace to overcome curbs during real-world conditions.

Automated Curb Recognition and Negotiation for Robotic Wheelchairs

Common electric powered wheelchairs cannot safely negotiate architectural barriers (i.e., curbs) which could injure the user and damage the wheelchair. Robotic wheelchairs have been developed to address this issue; however, proper alignment performed by the user is needed prior to negotiating curbs. Users with physical and/or sensory impairments may find it challenging to negotiate such barriers. Hence, a Curb Recognition and Negotiation (CRN) system was developed to increase user's speed and safety when negotiating a curb. This article describes the CRN system which combines an existing curb negotiation application of a mobility enhancement robot (MEBot) and a plane extraction algorithm called Polylidar3D to recognize curb characteristics and automatically approach and negotiate curbs. The accuracy and reliability of the CRN system were evaluated to detect an engineered curb with known height and 15 starting positions in controlled conditions. The CRN system successfully recognized curbs at 14 out of 15 starting positions and correctly determined the height and distance for the MEBot to travel towards the curb. While the MEBot curb alignment was 1.5 ± 4.4°, the curb ascending was executed safely. The findings provide support for the implementation of a robotic wheelchair to increase speed and reduce human error when negotiating curbs and improve accessibility.

Usability evaluation of attitude control for a robotic wheelchair for tip mitigation in outdoor environments

Tips and falls are the most prominent causes of wheelchair accidents that occur when driving on uneven terrains and less accessible environments. The Mobility Enhancement Robotic Wheelchair (MEBot) was designed to improve the stability of Electric Powered Wheelchairs (EPW) when driving over these environments. MEBot offers six independently height-adjustable wheels to control attitude of its seat over uneven and angled terrains. Its attitude control application uses an inertial measurement unit to detect seat angles changes to adjust each wheel-height accordingly. MEBot was compared to commercial EPWs in terms of EPW performance (seat angle changes and response time) and participant perception (satisfaction and task-load demand) towards each device. Ten participants drove their own EPW and MEBot for five trials each through driving tasks that replicated outdoor environments. Results showed less change in the pitch angle when driving up and down a 10° slope using MEBot (5.6 ± 1.6°, 6.6 ± 0.5°) compared to the participants' own EPW (14.6 ± 2.6°, 12.1 ± 2.6°). However, MEBot required 7.8 ± 3.0 s to self-adjust to the minimum angle when driving over the tasks. Participants reported no difference in satisfaction and task load demand between EPWs due to similarities in comfort and ease-of-use. Improving the speed and efficiency of MEBot's attitude control application will be addressed in future work based upon participants' feedback.

Improving wheelchair route planning through instrumentation and navigation systems

Route planning is an important tool to reach points of interest. The current technology offers options for public transportation and pedestrians on the road and sidewalks, respectively. However, for people who use electric powered wheelchairs (EPW) as their primary means of mobility, the level of accessibility and EPW battery consumption are important during route planning. This paper introduces the concept of an accessible route navigation application to reduce EPW battery consumption. The application, called eNav, uses five layers of information including OpenStreetMaps (OSM), airborne laser scanner (ALS), Point-of-Interests (POIs), public transportation, and crowdsourcing. eNav collects these layers of information to provide the shortest, most accessible, and most comfortable routes that consume the least amount of EPW battery. Additionally, the paper presents the Mobility Enhancement roBot (MEBot), a legged-wheeled power wheelchair, to drive over architectural barriers and less accessible environments. The paper proposes the use of MEBot as a sixth layer of information to inform eNav and road authorities about sidewalk/route conditions, to improve road accessibility, and to provide an energy efficient route planning for non-MEBot users.

A Heuristic Approach to Overcome Architectural Barriers Using a Robotic Wheelchair

The Mobility Enhancement roBotic (MEBot) wheelchair was developed to improve the safety and accessibility of wheelchair users when facing architectural barriers. MEBot uses pneumatic actuators attached to its frame and six wheels to provide curb ascending/descending for heights up to 20.3 cm. To improve MEBot's application, this study used a heuristic approach with power wheelchair users to evaluate and improve the MEBot application at different curb heights. Wheelchair users were trained on MEBot's features to operate its curb ascending/descending application. Three trials were carried out with wheelchair users ascending and descending three curbs of different height. Quantitative variables were analyzed to improve the sequential steps to ascend/descend curbs. Additionally, the application's effectiveness and efficiency were measured by the number of completed tasks, change in seat angle, and task completion time. Results showed that participants completed each trial and applied alternative strategies to traverse different curb heights. Furthermore, results suggested the combination and/or re-arrangement of steps to reduce task completion time. MEBot demonstrated its effectiveness to ascend/descend different curb heights with a heterogeneous participant sample. Future work will incorporate participant's most efficient strategies to improve the ascending/ascending process and the efficiency of the MEBot application.

Usability Evaluation of a Novel Robotic Power Wheelchair for Indoor and Outdoor Navigation

OBJECTIVE

To compare the Mobility Enhancement roBotic (MEBot) wheelchair's capabilities with commercial electric-powered wheelchairs (EPWs) by performing a systematic usability evaluation.

DESIGN

Usability in effectiveness, efficacy, and satisfaction was evaluated using quantitative measures. A semistructured interview was employed to gather feedback about the users' interaction with MEBot.

SETTING

Laboratory testing of EPW driving performance with 2 devices in a controlled setting simulating common EPW driving tasks.

PARTICIPANTS

A convenience sample of expert EPW users (N=12; 9 men, 3 women) with an average age of 54.7±10.9 years and 16.3± 8.1 years of EPW driving experience.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Powered mobility clinical driving assessment (PMCDA), Satisfaction Questionnaire, National Aeronautics and Space Administration's Task Load Index.

RESULTS

Participants were able to perform significantly higher number of tasks (P=.004), with significantly higher scores in both the adequacy-efficacy (P=.005) and the safety (P=.005) domains of the PMCDA while using MEBot over curbs and cross-slopes. However, participants reported significantly higher mental demand (P=.005) while using MEBot to navigate curbs and cross-slopes due to MEBot's complexity to perform its mobility applications which increased user's cognitive demands.

CONCLUSIONS

Overall, this usability evaluation demonstrated that MEBot is a promising EPW device to use indoors and outdoors with architectural barriers such as curbs and cross-slopes. Current design limitations were highlighted with recommendations for further improvement.