Participatory Action Design and Engineering of Powered Personal Transfer System for Wheelchair Users: Initial Design and Assessment.

Caregivers that assist with wheelchair transfers are susceptible to back pain and occupational injuries. The study describes a prototype of the powered personal transfer system (PPTS) consisting of a novel powered hospital bed and a customized Medicare Group 2 electric powered wheelchair (EPW) working together to provide a no-lift solution for transfers. The study follows a participatory action design and engineering (PADE) process and describes the design, kinematics, and control system of the PPTS and end-users' perception to provide qualitative guidance and feedback about the PPTS. Thirty-six participants (wheelchair users (n = 18) and caregivers (n = 18)) included in the focus groups reported an overall positive impression of the system. Caregivers reported that the PPTS would reduce the risk of injuries and make transfers easier. Feedback revealed limitations and unmet needs of mobility device users, including a lack of power seat functions in the Group-2 wheelchair, a need for no-caregiver assistance/capability for independent transfers, and a need for a more ergonomic touchscreen. These limitations may be mitigated with design modifications in future prototypes. The PPTS is a promising robotic transfer system that may aid in the higher independence of powered wheelchair users and provide a safer solution for transfers.

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.

Evaluation of Electric and Air-Powered Shopping Scooters in Grocery Stores.

OBJECTIVE: The purpose of this study was to further previous research and gather additional information regarding the usage of motorized shopping scooters as well as feedback for improvements to an air-powered scooter. METHODS: Online surveys were used to assess individuals' shopping characteristics and experience using the motorized scooters and to gather feedback from store employees regarding their experience. K-Means clustering analysis was used to determine user demographics who chose to use the air-powered scooter versus the electric-powered scooter while shopping. RESULTS: A total of 127 individuals provided informed consent, 65 individuals from site 1 and 62 individuals from site 2. One hundred twenty participants met the inclusion criteria and completed the survey. K-Means clustering found that age, type of personal mobility device, shopping bill total, and frequency using a motorized shopping scooter to be significant factors in whether individuals chose to use an air-powered scooter or electric-powered scooter. CONCLUSIONS: Motorized shopping scooters are in high demand and used by a wide variety of individuals, yet electric-powered scooters are commonly unavailable because of having dead batteries or all the devices being in use. Air-powered scooters may serve as a practical replacement for the current electric-powered scooters found in grocery and retail stores.

Current State, Needs, and Opportunities for Wearable Robots in Military Medical Rehabilitation and Force Protection.

Despite advances in wearable robots across various fields, there is no consensus definition or design framework for the application of this technology in rehabilitation or musculoskeletal (MSK) injury prevention. This paper aims to define wearable robots and explore their applications and challenges for military rehabilitation and force protection for MSK injury prevention. We conducted a modified Delphi method, including a steering group and 14 panelists with 10+ years of expertise in wearable robots. Panelists presented current wearable robots currently in use or in development for rehabilitation or assistance use in the military workforce and healthcare. The steering group and panelists met to obtain a consensus on the wearable robot definition applicable for rehabilitation or primary injury prevention. Panelists unanimously agreed that wearable robots can be grouped into three main applications, as follows: (1) primary and secondary MSK injury prevention, (2) enhancement of military activities and tasks, and (3) rehabilitation and reintegration. Each application was presented within the context of its target population and state-of-the-art technology currently in use or under development. Capturing expert opinions, this study defines wearable robots for military rehabilitation and MSK injury prevention, identifies health outcomes and assessment tools, and outlines design requirements for future advancements.

Development of an advanced mobile base for personal mobility and manipulation appliance generation II robotic wheelchair.

BACKGROUND: This paper describes the development of a mobile base for the Personal Mobility and Manipulation Appliance Generation II (PerMMA Gen II robotic wheelchair), an obstacle-climbing wheelchair able to move in structured and unstructured environments, and to climb over curbs as high as 8 inches. The mechanical, electrical, and software systems of the mobile base are presented in detail, and similar devices such as the iBOT mobility system, TopChair, and 6X6 Explorer are described. FINDINGS: The mobile base of PerMMA Gen II has two operating modes: "advanced driving mode" on flat and uneven terrain, and "automatic climbing mode" during stair climbing. The different operating modes are triggered either by local and dynamic conditions or by external commands from users. A step-climbing sequence, up to 0.2 m, is under development and to be evaluated via simulation. The mathematical model of the mobile base is introduced. A feedback and a feed-forward controller have been developed to maintain the posture of the passenger when driving over uneven surfaces or slopes. The effectiveness of the controller has been evaluated by simulation using the open dynamics engine tool. CONCLUSION: Future work for PerMMA Gen II mobile base is implementation of the simulation and control on a real system and evaluation of the system via further experimental tests.

Usability and Vibration Analysis of a Low-Profile Automatic Powered Wheelchair to Motor Vehicle Docking System.

The QLX is a low-profile automatic powered wheelchair docking system (WDS) prototype developed to improve the securement and discomfort of wheelchair users when riding in vehicles. The study evaluates the whole-body vibration effects between the proposed QLX and another WDS (4-point tiedown system) following ISO 2631-1 standards and a systematic usability evaluation. Whole-body vibration analysis was evaluated in wheelchairs using both WDS to dock in a vehicle while riding on real-world surfaces. Also, participants rated the usability of each WDS while driving a wheelchair and while riding in a vehicle in driving tasks. Both WDSs showed similar vibration results within the vibration health-risk margins; but shock values below health-risk margins. Fifteen powered wheelchair users reported low task load demand to operate both WDS; but better performance to dock in vehicles with the QLX (p = 0.03). Also, the QLX showed better usability (p < 0.01), less discomfort (p's < 0.05), and greater security compared to the 4-point tiedown while riding in a vehicle (p's < 0.05). Study findings indicate that both WDS maintain low shock exposure for wheelchair users while riding vehicles, but a better performance overall to operate the QLX compared to the 4-point tiedown system; hence enhancing user's autonomy to dock in vehicles independently.

Anthropomorphic model rigid loading indenter with embedded sensor development for wheelchair cushion standard testing.

Develop an anthropomorphic model cushion rigid loading indenter with embedded sensors (AMCRLI-ES) to assess compression and shear forces at key locations such as trochanters and ischial tuberosities. The sensor design was optimized using finite element analysis. The AMCRLI-ES was designed with the same dimensions as specified in ISO 16840-2 tests. The AMCRLI-ES is divided into eight independent sections, and each section consists of one 3-axis load cell sensor to measure compression and shear forces normal to the compression direction. Six commercial cushions were tested using the AMCRLI-ES with standard ISO 16840-2 testing procedures. Statistical differences were found for energy dissipation between cushions. Statistical differences (p < 0.001) were found in all stiffness values. Test results showed that energy dissipation (ED) was correlated with hysteresis at 500 N with moderate to high Pearson product correlation r = -0.537, p = 0.022. The hysteresis at 250 N did not show a statistical correlation with ED. The AMCRLI-ES demonstrated the ability to measure compression and shear forces at key locations on the cushion including the thigh, trochanter, ischial tuberosity, and sacral area. It provides in-depth information about how the weight was distributed on the cushions.

Comparison of trunk mechanics and spatiotemporal outcomes in caregivers using a robotic assisted transfer device and a mobile floor lift.

OBJECTIVE: The purpose of this study was to compare trunk mechanics, distance covered, and average instantaneous velocity and acceleration recorded with caregivers performing transfer tasks using a research mannequin with both a prototype robotic assisted transfer device (RATD) and a mobile floor lift. DESIGN: Cross-Sectional. SETTING: Biomechanics Lab and Human Engineering Research Laboratories. PARTICIPANTS: Caregivers (N = 21). INTERVENTION: Robotic Assisted Transfer Device. OUTCOME MEASURES: Range of flexion-extension, lateral bend, and axial rotation; distance covered; average instantaneous velocity and acceleration. RESULTS: Caregivers performing transfers using the RATD as compared to when using the moble floor lift reported significantly smaller range of trunk flexion-extension, lateral bending, and axial rotation, and reported lower pelvic based distance covered and slower average instantaneous velocity and acceleration (P < 0.001). CONCLUSION: The design and usability of a RATD indicates design driven mobility advantages over clinical standard mobile floor lifts due to its ability to expand the workspace while further reducing risk factors for low back pain. While the concept is promising, further testing is required to address limitations and confirm the concept for clinical applications.

Participatory action design and engineering of a manual wheelchair virtual coach including in-home and community usage.

BACKGROUND: Current clinical practice guidelines (CPG) recommend periodic pressure redistribution (PR) to alter sitting pressure and reduce the risk of developing pressure injuries (PI). Individuals who have strength and trunk stability are asked to perform PR such as wheelies, leaning laterally, and forward-leaning to minimize the duration of pressure acting on the same region of the body. OBJECTIVE: Our long-term objective is to build upon previous research and development to create a more effective device for improving PR training and adherence to CPG among manual wheelchair users (MWU). Through this study, we employed a participatory action design and engineering (PADE) approach in developing the hardware and user interface to increase the likelihood of eventually yielding a device effective for both MWU and clinicians. PARTICIPANTS: Focus Groups: Ten clinicians - 6 physical therapists, 3 occupational therapists, and one registered nurse, and 10 MWU with spinal cord injuries (SCI) who reported using their wheelchairs 40-80 h per week. Five-Day Assessment: Five male MWU with SCI who had been wheelchair users for 18.5 ± 16.2 years. Four-Week Investigation: The 7 participants with SCI were 5 males and 2 females, who had been wheelchair users for 24.7 ± 17.0 years. METHODS: A PADE approach was used to improve upon a manual wheelchair virtual coaching system for people with SCI. The system comprises a seat support instrumented with force sensors, software algorithms to detect PR, and a smart phone app for user interface. The methods included three stages: multiple focus groups, a five-day evaluation phase with participants using their own wheelchairs in their homes and communities, and a 4-week assessment with improvements made based on the 5-day results by users with their own wheelchairs in their homes and communities. RESULTS: The focus groups yielded guidance for ergonomics, user interface, charging frequency, and key dimensions and mass. The 5-day study identified mechanical, electrical, and connectivity challenges, which were resolved before the 4-week study. The 4-week trial suggested that participants performed PR less frequently than clinically recommended and provided an indication of the types of maneuvers that they performed. CONCLUSION: A prototype manual wheelchair virtual coaching system was developed using a PADE process. The system was able to detect and record PR in home and community environments. Following improvements identified in this study, a future version will be tested with additional users to determine whether it can improve adherence to PR guidance.

Air-powered shopping carts in grocery stores: a pilot study.

PURPOSE: Motorized shopping carts found at grocery and retail stores provide mobility for those who have difficulty walking through the store or pushing a regular cart. The purpose of this study was to understand the usage of motorized carts in grocery stores and pilot test an air-powered cart to determine its feasibility as a replacement for electric-powered carts as well as identify areas for improvement and preferred users. METHODS: Users were asked to complete an online survey that assessed their shopping characteristics and experience using the motorized cart. K-Means clustering determined user demographics who chose to use the air-powered carts versus the electric-powered carts. Open-ended comments for improvements were also collected. RESULTS: A total of 65 participants were provided informed consent, 60 participants met inclusion criteria and completed the survey. A majority of the air-powered (N = 29, 91%) and electric-powered (N = 11, 73%) cart users had a positive experience. Clustering found age and type of mobility device owned were significant whether participants chose the air-powered or electric-powered carts. Most suggested improvements for the air-powered carts were better braking, higher speed and a bigger basket while a longer battery life was most suggested for electric-powered carts. CONCLUSIONS: Motorized shopping carts are used by a wide variety of individuals. Individuals aged 54 or younger and do not own a mobility device chose to use air-powered more than electric-powered carts. The functional capabilities of the air-powered carts demonstrated their potential to serve as practical replacements for electric-powered carts found in grocery and retail stores.Implications for rehabilitationThe availability and reliability of motorized shopping carts at retail stores are integral for individuals with physical impairments to complete their shopping needs.The development of novel assistive devices such as air-powered carts provides improved experiences and quality of life.Integrating end-user feedback during the design of assistive technologies is paramount for meeting actual needs.

Clinical and Ergonomic Comparison Between a Robotic Assisted Transfer Device and a Mobile Floor Lift During Caregiver-Assisted Wheelchair Transfers.

BACKGROUND: The robotic assisted transfer device was developed as an updated lift technology to reduce adjustments in posture while increasing capabilities offered by transfer devices. The purpose of this study was to compare the trunk biomechanics of a robotic assisted transfer device and a mechanical floor lift in the transfer of a care recipient by a caregiver during essential transfer tasks. METHODS: Investigators enrolled 28 caregiver/care recipient dyads to complete 36 transferring tasks. Surface electromyography for the back muscles and motion data for trunk range of motion were collected for selected surfaces, phase, and direction tasks using a robotic assisted transfer device and a mechanical floor lift. RESULTS: Robotic assisted transfer device transfers required significantly smaller range of trunk flexion (P < 0.001), lateral bend (P < 0.001), and axial rotation (P = 0.01), in addition to smaller distance covered (P < 0.001), average instantaneous velocity (P = 0.01), and acceleration (P < 0.001) compared with a mobile floor lift. The robotic assisted transfer device transfers required significantly smaller peak erector spinae (left: P = 0.001; right: P < 0.001) and latissimus dorsi (right: P < 0.001) and integrated erector spinae left (P = 0.001) and latissimus dorsi right (P = 0.01) electromyography signals compared with the floor lift. CONCLUSIONS: The robotic assisted transfer device provides additional benefits to mobile floor lifts which, coupled with statistically lower flexion, extension, and rotation, may make them an appealing alternative intervention.

TECHNOLOGY TRANSFER ASSISTANCE PROJECT BRINGS VA HEALTH CARE IDEAS TO LIFE.

Clinicians and staff of the Department of Veterans Affairs Health Care System (VA), who provide services to veterans, have invented many devices and methods for improving veterans' lives. However, translating those inventions to the market has been a challenge due to limited collaboration between the clinical inventors and the scientists, researchers, and engineers who can produce the prototypes necessary for licensing the technology. The VA Technology Transfer Program office and the Human Engineering Research Laboratories, a research laboratory with experience with developing prototypes and licensing technology, jointly developed a program called the Technology Transfer Assistance Project (TTAP) to bridge the gap between clinical inventors and prototypes ready for licensing. This paper describes TTAP and provides examples of the first inventions that were developed or enhanced through TTAP.

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.

Assessment of Muscle Activation of Caregivers Performing Dependent Transfers With a Novel Robotic-Assisted Transfer Device Compared With the Hoyer Advance.

OBJECTIVE: The purpose of this study was to compare muscle activity in caregivers while using a novel robotic-assisted transfer device (Strong Arm) to a clinical standard of care (Hoyer Advance). DESIGN: A quasi-experimental design was used in which 20 caregivers (33 ± 15 yrs old) performed transfers with three surfaces (toilet, bench, and shower chair) with the Strong Arm and Hoyer Advance. Transfer completion time (seconds), peak percentage surface electromyography (EMG), and integrated EMG of the bilateral erector spinae, latissimus dorsi, pectoralis major and anterior deltoid were measured. RESULTS: Caregivers required less transfer time when transferring from wheelchair to surface using the Hoyer Advance (P = 0.011, f = 0.39). For the lower back, significantly lower peak percentage EMGs were found using Strong Arm in 50% and for the integrated EMG in 25% of the cases, with the remaining cases showing no significant differences. For the shoulder, significantly lower peak percentage EMG values were found using Strong Arm in 19% of transfers and lower integrated EMG was found in 25% of transfers when using the Hoyer Advance, with the remaining cases showing no significant differences. CONCLUSION: Although back muscle activation during Strong Arm transfers is statistically, but not clinically, lower, additional features that couple with significantly lower muscle activation make it an alternative to the clinical standard for further research and possible clinical applicability.

VA TECHNOLOGY TRANSFER PROGRAM RESPONDS TO COVID-19 PANDEMIC.

The COVID-19 pandemic stressed healthcare systems all over the world. Two primary challenges that healthcare systems faced were a shortage of personal protective equipment and the need for new technologies to handle infection prevention for staff and patients. The Department of Veteran's Affairs (VA) Technology Transfer Program responded by prioritizing the development of innovations in the Technology Transfer Assistance Project which addressed the pandemic. This paper describes several innovations that addressed the needs of the VA healthcare system during the pandemic and how they were rapidly developed.

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.

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.

Accessible machining for people who use wheelchairs.

Despite the Americans with Disabilities Act mandate for reasonable accommodations, wheelchair users are often placed in the role of observer and note-taker when learning machining and fabrication skills due to a lack of accessibility. The focus of this case study report is to identify and develop reasonable accommodations for wheelchair users in an academic machine shop environment to address accessibility limitations of original equipment manufacturer (OEM) machines. Individual wheelchair users working and learning within the Human Engineering Research Laboratories (HERL) were observed and interviewed about their experiences using the machine shop equipment without modifications, followed by further observations after accommodations were implemented.

Design and operation verification of an automated pressure mapping and modulating seat cushion for pressure ulcer prevention.

A sensorized air cell-based seat cushion system was developed to address the issues of loading magnitude and duration at a sitting interface to aid in reducing risk of sitting acquired pressure ulcers. This system is capable of pressure mapping, redistribution, and offloading which were verified using an anthropomorphic model and a human subject. The system is comprised of an air cell array cushion, a pneumatic control unit, and a graphical user interface. ISO load deflection testing confirmed that the cushion's loading response is comparable to commercial air cell-based seat cushions. Testing demonstrated that the internal pressure of the air cells are indicative of interface pressure and can be used as input to pressure modulating algorithms. Uniform pressure distribution was achieved through automated pressure redistribution algorithm implementation where the immersion of a subject into the seat cushion increased and interface pressure decreased. High pressure point identification and automatic offloading were performed in which newly created high pressure points were addressed using subsequent redistribution. Pressure mapping enabled offloading and redistribution can objectively manage the effects of loading magnitude and duration at the sitting interface.

Assessment of Usability and Task Load Demand Using a Robot-Assisted Transfer Device Compared With a Hoyer Advance for Dependent Wheelchair Transfers.

OBJECTIVE: Manual lifting can be burdensome for people who care for power wheelchair users. Although technologies used for dependent transfers are helpful, they have shortcomings of their own. This study compares the usability and task load demand of a novel robot-assisted transfer device to a clinical standard when performing dependent transfers. DESIGN: A cross-sectional study was conducted to assess caregivers (N = 21) transferring a 56-kg mannequin with the Strong Arm and Hoyer Advance at three transfer locations. Feedback was gathered through qualitative surveys. RESULTS: Usability was significant in multiple areas important for transfers. Caregiver fatigue and discomfort intensity were reduced, and the Strong Arm was preferred at the three transfer locations. Device ease and efficiency favored Strong Arm at two stations as was discomfort frequency. In addition, physical demand, frustration, and effort were significantly lower using Strong Arm compared with the Hoyer Advance. CONCLUSIONS: Compared with the Hoyer, participants favored Strong Arm for transfer usability and task load demand. However, further Strong Arm developments are needed.