Wheelchair Joystick Research Articles

The effect of differences in powered wheelchair joystick shape on subjective and objective operability

Various-shaped joysticks steer electric-powered wheelchairs (EPWs); however, an operability evaluation has not been fully conducted. This study evaluated the subjective and objective operability of various-shaped joysticks in 22 younger and 22 older adults. Participants operated an EPW on an experimental course using nine different-shaped joysticks, before ranking each joystick by their operability (1 = best, 9 = worst) as a primary outcome. Movement time (MT) and driving accuracy (DA) were also measured. Despite no significant differences in the primary outcome between joysticks, the I-shaped joystick with rounded tips (neutral grip) was ranked higher than the others. MT did not differ between joysticks, but DA was higher for the thin-columnar I-shaped joystick (pinch grip) than for the U- and T-shaped joysticks (pronated grip). MT and DA scores for young adults were significantly better than those for older adults. Further studies should be conducted to clarify possible factors related to EPW operability.

VP.13 Updates on the development of the spinal muscular atrophy - person-reported outcome (SMA-PRO): A caregiver and self-proxy performance measure for child

There is a need for person-reported outcome measures for SMA. The PEDI-CAT is a caregiver-reported measure used to describe functional skill performance. Convergent validity of the PEDI-CAT with SMA phenotypes was established, and Rasch analysis of the full item bank revealed representation of abilities for SMA III and for daily activities for SMA II, but a floor effect for SMA I. Results led to the development of a new measure to include a larger item bank with caregiver and self-proxy options. Goals were 1) To describe the SMA PRO test development, including focus groups and cognitive-testing for item content 2) To describe the development of branching logic for data collection and 3) To report interim results on data collected with the new measure. Clinicians with expertise in SMA participated in 4 focus groups. Clinicians reviewed the results of the Rasch analysis and discussed content, scoring and clarity for the 76 daily activities and 105 mobility items. Thirty mobility and 69 daily activities items were added to address the floor effect and include items for infants and adults. A power wheelchair domain was created with 35 items and illustrations including "maintaining hand on wheelchair joystick while driving on uneven terrain." Illustrations were re-created to increase relevance for adults and children. The new items and illustrations were reviewed and several items were discarded due to perception of redundancy. Clinicians then conducted cognitive interviews with 15 study participants (7 caregivers and 8 adolescents and adults with SMA). A maximum of 30 items with accompanying illustrations were reviewed at each interview with probing questions including, "In your own words, what do you think this question is asking?" and "Does the illustration match the item wording?" Cognitive interview results were collated and items were further edited. The final items and illustrations were added to a database, and branching logic was established based on pre-determined "stopping rules" to minimize the total number of items required for each respondent. Item surveys were sent to participants and caregivers via a secure email, and data was collected prospectively. At the time of this interim study point, 58 surveys had been completed (16 "non-sitters," 38 "sitters" and 25 "walkers") across 4 functional domains. Data collection is underway, and a full analysis will be performed in order to validate the measure.

Evaluating surface EMG control of motorized wheelchairs for amyotrophic lateral sclerosis patients

BackgroundThis study evaluated a novel control method for patients unable to independently control powered wheelchairs. Patients with amyotrophic lateral sclerosis often require a wheelchair but struggle with sufficient hand dexterity required for joystick control making them a population that needs this type of control method.MethodsThe study employed a novel control mechanism, using electromyography surface sensors applied to temporalis muscles able to measure the myoelectric voltage. Pattern and magnitude control of muscle contraction allowed for steering intention recognition and were used to manipulate their power wheelchair joystick. Four patients ages 51 to 69, two female and two male with amyotrophic lateral sclerosis, conducted Wheelchair Skills Test developed by Dalhousie University and were surveyed on the experience’s Clinical Global Impression of Change.ResultsFindings showed independent steering was capable for patients without hand function and provided recommendations for improved human-machine interface. All patients demonstrated the ability to engage the system, with varying precision, for driving their wheelchair in a controlled environment.ConclusionsThree patients in the pilot trial reported the highest score of clinical global impression of change, all of whom had lost independent control of their wheelchair joystick. Patient four retained impaired hand dexterity for joystick control and reported negative impression of change, comparatively. Feedback from the study will be leveraged to improve training outcomes.Trial registration Subjects provided signed informed consent according to the Declaration of Helsinki to enter the study that was approved by the Mayo Clinic Institutional Review Board in Rochester, Minnesota. The study is registered on ClinicalTrials.gov under identifier NCT04800926 as of March 14, 2021 retrospectively registered.

Selecting a Best Compromise Direction for a Powered Wheelchair Using PROMETHEE.

Research is described that determines the direction that a powered wheelchair will take, using the preference ranking organization method for enrichment of evaluations II (PROMETHEE II). This is the first time that this sort of decision making has been used in this type of application. A user suggests a desired direction and speed, and the decision-making system suggests a safe direction for a wheelchair. The two are mixed, and the wheelchair then tends to avoid obstacles. The inputs come from a powered wheelchair joystick and two ultrasonic transducers fixed onto the wheelchair, and the final direction is a simulation of the desired direction and a direction that moves the wheelchair away from obstacles. The arrangement assists a disabled driver to steer their wheelchairs. It uses a systematic decision-making process, and this paper presents the process and a new way of selecting a best compromise direction. Sensitivity analysis is employed to explore potentially suitable directions as uncertainty and risk may be present. A suitable direction is selected that provides a robust solution. The user would be able to override the suggestions by the PROMETHEE II system by holding the joystick in a position.

Human-Machine Interface for a Smart Wheelchair

The paper describes the integration of hardware and software with sensor technology and computer processing to develop the next generation intelligent wheelchair. The focus is a computer cluster design to test high performance computing for smart wheelchair operation and human interaction. The LabVIEW cluster is developed for real-time autonomous path planning and sensor data processing. Four small form factor computers are connected over a Gigabit Ethernet local area network to form the computer cluster. Autonomous programs are distributed across the cluster for increased task parallelism to improve processing time performance. The distributed programs operating frequency for path planning and motion control is 50Hz and 12.3Hz for 0.3 megapixel robot vision system. To monitor the operation and control of the distributed LabVIEW code, network automation is integrated into the cluster software along with a performance monitor. A link between the computer motion control program and the wheelchair joystick control of the drive train is developed for the computer control interface. A perception sensor array and control circuitry is integrated with the computer system to detect and respond to the wheelchair environment. Multiple cameras are used for image processing and scanning laser rangefinder sensors for obstacle avoidance in the cluster program. A centralized power system is integrated to power the smart wheelchair along with the cluster and sensor feedback system. The on board computer system is evaluated for cluster processing performance for the smart wheelchair, incorporating camera machine vision and LiDAR perception for terrain obstacle detection, operating in urban scenarios.

Enhanced Control to Improve Navigation and Manipulation of Power Wheelchairs.

Our team developed a mobile wheelchair control kit designed to allow power wheelchair users the ability to maneuver their wheelchair without the need to manipulate a joystick with their hands. A smartphone and its internal accelerometer sensor was used to detect the vector of gravity, and thus detecting the pitch and roll. The wheelchair control system was tested with the phone attached in three mounting positions: hand held, hat and arm band and compared to the manipulation using the wheelchair joystick. To determine the viability of the commercialization of this kit as well as which features to further develop, a customer discovery was completed. Over a hundred interviews of power wheelchairs users, therapists, care takers, manufacturers, dealers, and assistive technology professionals were conducted at clinics, tradeshows, disabilities support groups, and rehabilitation organizations. After discovering the needs of the customers, collision avoidance was implemented into the control kit and back up cameras were added into the smart phone app to allow for the camera view to be seen without additional screens attached to the wheelchair. Future work will test these new design features and will concentrate on removing excess weight from the control kit. Improving the ease of installation of the kit to any power wheelchair will also be a focus.

The Control System Based on Extended BCI for a Robotic Wheelchair

In most cases, the movement of wheelchairs is controlled by disabled people using a joystick or by an accompanying person. Significantly disabled patients need alternative control methods without using the wheelchair joystick because it is undesirable or impossible for these patients. In this article, we present the implementation of a robotic wheelchair based on a powered wheelchair that is controlled not by the joystick but by the onboard computer that receives and processes data from the extended brain-computer interface (extended BCI). Under this term we understand the robotic complex control system with simultaneous independent alternative control channels. In this robotic wheelchair version the BCI works with voice and gesture control channels.

Differences in outcomes between the JoyBar control and standard wheelchair joystick control on two maneuverability tasks: a pilot study

Purpose: To determine if older adult, novice wheelchair users who drive a power wheelchair with a JoyBar control complete maneuverability tasks in less time and with less error than those who drive a power wheelchair with a standard joystick control.Materials and methods: A parallel randomized controlled trial design conducted at a medical rehabilitation and research centre with ambulatory older adults aged 60 and above (n = 27). The intervention was the JoyBar alternative wheelchair control. The primary outcome measure was total time to complete each of the two maneuverability tasks. The secondary outcome measure was total number of errors during each of the maneuverability tasks.Results: An independent, two sampled t-test was conducted and revealed that the JoyBar group took a greater amount of time to complete both maneuverability tasks than the control group (p < .05). No significant differences (p < .05) were found in rates of error on either task between the JoyBar and joystick groups.Conclusions: Maneuverability of a powered wheelchair by novice wheelchair users was not improved through the use of the JoyBar when compared to a standard wheelchair joystick, as measured by rates of error and time to complete maneuverability tasks.Implications for rehabilitationClients who are new to powered wheelchair use may perform maneuverability tasks faster, with equivalent accuracy, using a standard joystick versus the JoyBar.Clients who use a JoyBar may require adjustments to the programming of their wheelchair to ensure optimal performance.Additional training may be required to achieve proficiency in maneuverability tasks with a JoyBar versus a standard joystick.

Virtual reality body motion induced navigational controllers and their effects on simulator sickness and pathfinding.

Virtual reality (VR) navigation is usually constrained by plausible simulator sickness (SS) and intuitive user interaction. The paper reports on the use of four different degrees of body motion induced navigational VR controllers, a TiltChair, omni-directional treadmill, a manual wheelchair joystick (VRNChair), and a joystick in relation to a participant's SS occurrence and a controller's intuitive utilization. Twenty young adult participants utilized all controllers to navigate through the same VR task environment in separate sessions. Throughout the sessions, SS occurrence was measured from a severity score by a standard SS questionnaire and from body sway by a center of pressure path length with eyes opened and closed. SS occurrence did not significantly differ among the controllers. However, time spent in VR significantly contributed to SS occurrence; hence, a few breaks to minimize SS should be interjected throughout a VR task. For all task trials, we recorded the participant's travel trajectories to investigate each controller's intuitive utilization from a computed traversed distance. Shorter traversed distances indicated that participants intuitively utilized the TiltChair with a slower speed; while longer traversed distances indicated participants struggled to utilize the omni-directional treadmill with a unnaturalistic stimulation of gait. Therefore, VR navigation should use technologies best suited for the intended age group that minimizes SS, and produces intuitive interactions for the participants.

Training wheelchair navigation in immersive virtual environments for patients with spinal cord injury – end-user input to design an effective system

Purpose: A user-centred design was used to develop and test the feasibility of an immersive 3D virtual reality wheelchair training tool for people with spinal cord injury (SCI).Method: A Wheelchair Training System was designed and modelled using the Oculus Rift headset and a Dynamic Control wheelchair joystick. The system was tested by clinicians and expert wheelchair users with SCI. Data from focus groups and individual interviews were analysed using a general inductive approach to thematic analysis.Results: Four themes emerged: Realistic System, which described the advantages of a realistic virtual environment; a Wheelchair Training System, which described participants’ thoughts on the wheelchair training applications; Overcoming Resistance to Technology, the obstacles to introducing technology within the clinical setting; and Working outside the Rehabilitation Bubble which described the protective hospital environment.Conclusions: The Oculus Rift Wheelchair Training System has the potential to provide a virtual rehabilitation setting which could allow wheelchair users to learn valuable community wheelchair use in a safe environment. Nausea appears to be a side effect of the system, which will need to be resolved before this can be a viable clinical tool.Implications for RehabilitationImmersive virtual reality shows promising benefit for wheelchair training in a rehabilitation setting.Early engagement with consumers can improve product development.

Innovative Power Wheelchair Control Interface: A Proof-of-Concept Study.

Some people without independent mobility are candidates for powered mobility but are unable to use a traditional power wheelchair joystick. This proof-of-concept study tested and further developed an innovative method of driving power wheelchairs for people whose impairments prevent them from operating commercial wheelchair controls. Our concept, Self-referenced Personal Orthotic Omni-purpose Control Interface (SPOOCI), is distinguished by referencing the control sensor not to the wheelchair frame but instead to the adjacent proximal lower-extremity segment via a custom-formed orthosis. Using a descriptive case-series design, we compared the pre-post functional power wheelchair driving skill data of 4 participants, measured by the Power Mobility Program, using descriptive analyses. The intervention consisted of standard-care power wheelchair training during 12 outpatient occupational or physical therapy sessions. All 4 participants who completed the 12-wk intervention improved their functional power wheelchair driving skills using SPOOCI, but only 3 were deemed safe to continue with power wheelchair driving.

Resistopalatography as an assistive technology for users with spinal cord injuries.

Translating a desired user's input using conventional methods such as a keyboard and mouse for the computer, or a joystick for a wheelchair is a major challenge faced by users whom have no limb control. This paper describes an iteration of Resistopalatography, a method using the tongue as a pointing device to emulate the use of the hand for cursor movement and wheelchair control. The system employs force sensitive sensors located within the mouth on a dental retainer plate to measure the tongue's pressure against the hard palate. The position and force of tongue against the sensors can be translated into mouse cursor or wheelchair joystick equivalents.

Preliminary evaluation of variable compliance joystick for people with multiple sclerosis

Upper-limb fatigue is a common problem that may restrict people with multiple sclerosis (MS) from using their electric powered wheelchair effectively and for a long period of time. The objective of this research is to evaluate whether participants with MS can drive better using a variable compliance joystick (VCJ) and customizable algorithms than with a conventional wheelchair joystick. Eleven participants were randomly assigned to one of two groups. The groups used either the VCJ in compliant or noncompliant isometric mode and a standard algorithm, personally fitted algorithm, or personally fitted algorithm with fatigue adaptation running in the background in order to complete virtual wheelchair driving tasks. Participants with MS showed better driving performance metrics while using the customized algorithms than while using the standard algorithm with the VCJ. Fatigue adaptation algorithms are especially beneficial in improving overall task performance while using the VCJ in isometric mode. The VCJ, along with the personally fitted algorithms and fatigue adaptation algorithms, has the potential to be an effective input interface for wheelchairs.

Wheelchair control by head motion

Electric wheelchairs are designed to aid paraplegics. Unfortunately, these can not be used by persons with higher degree of impairment, such as quadriplegics, i.e. persons that, due to age or illness, can not move any of the body parts, except of the head. Medical devices designed to help them are very complicated, rare and expensive. In this paper a microcontroller system that enables standard electric wheelchair control by head motion is presented. The system comprises electronic and mechanic components. A novel head motion recognition technique based on accelerometer data processing is designed. The wheelchair joystick is controlled by the system?s mechanical actuator. The system can be used with several different types of standard electric wheelchairs. It is tested and verified through an experiment performed within this paper.

Advancements in Power Wheelchair Joystick Technology: Effects of Isometric Joysticks and Signal Conditioning on Driving Performance

An estimated 125,000 Americans with movement disorders that preclude independent mobility in a power wheelchair could benefit from improved control devices. We developed variable gain algorithm (VGA) software for our isometric joystick (IJ) that allows it to emulate a commercially available motion-sensing joystick (MSJ) in performance but retain the unique customizable features of an isometric control. Force sensing algorithm (FSA) software allowed the IJ to function as a simple isometric device. Using a Fitts' Law paradigm, we compared driving performance with floor targets using a standard MSJ and an IJ with both FSA and VGA software in 11 electric power wheelchair users with a variety of impairments. Outcome measures were reaction time (RT), movement time (MT), and driving accuracy (DA). The IJ with FSA had a significantly shorter RT than the MSJ (P < 0.0020). The IJ with FSA had a significantly longer MT than the MSJ to far targets (P < 0.0159). No differences were found between the IJ with VGA and the MSJ with respect to RT or MT. No differences in DA were found among any of the joysticks. VGA software allowed the IJ to function similarly to the MSJ with respect to RT, MT, and DA.

Capturing Hand Tremors with a Fuzzy Logic Wheelchair Joystick Controller

Capturing Hand Tremors with a Fuzzy Logic Wheelchair Joystick Controller

Wheelchair Joystick Circuitry Causes Unintended Starting

Wheelchair Joystick Circuitry Causes Unintended Starting

Modification of a Proportional Joystick to Incorporate Switch Outputs for Accessories

Integrating the control of accessory devices into a wheelchair joystick can both optimize function and improve aesthetics. Although the number of commercial systems having this feature is increasing, there is still a number of joystick controllers in the field that do not provide integrated accessory device control. This paper describes the design of an add-on system that allows the user to control both the wheelchair and accessory functions using a proportional joystick controller. The mode of operation is chosen with an external switch that can be mounted at any desired location. Accessory control can include both wheelchair functions, such as power recline, and external functions, such as an environmental control unit. The design is especially well suited as a retrofit to existing wheelchair control systems. A case report of an individual with quadriplegia is presented demonstrating a successful implementation of this system.