Wheelchair Model Research Articles

操縦者の位置を考慮した車椅子モデルを用いた段差進入時の危険性の検討

操縦者の位置を考慮した車椅子モデルを用いた段差進入時の危険性の検討

Low Cost Battery Operated Vehicle Using Joystick Control for Physically Challenged

Wheelchairs are used by people having difficulty in walking due to disability or some illness. The wheelchairs can either be self-propelled or can be moved by using the torque developed from the electric motors fitted to the wheels. The use of automated wheelchairs has largely increased as it does not require any muscular movement from the user. The various automated wheelchair models available in the market are of high cost and cannot be afforded by everyone in need. In this project, we aim to develop a low cost automated wheelchairWithout compromising its reliability. The wheelchair movement is controlled by the user via a thumb joystick. The control algorithm is implemented by using ATMEGA 328P.

Tongue interface based on surface EMG signals of suprahyoid muscles

The research described herein was undertaken to develop and test a novel tongue interface based on classification of tongue motions from the surface electromyography (EMG) signals of the suprahyoid muscles detected at the underside of the jaw. The EMG signals are measured via 22 active surface electrodes mounted onto a special flexible boomerang-shaped base. Because of the sensor’s shape and flexibility, it can adapt to the underjaw skin contour. Tongue motion classification was achieved using a support vector machine (SVM) algorithm for pattern recognition where the root mean square (RMS) features and cepstrum coefficients (CC) features of the EMG signals were analyzed. The effectiveness of the approach was verified with a test for the classification of six tongue motions conducted with a group of five healthy adult volunteer subjects who had normal motor tongue functions. Results showed that the system classified all six tongue motions with high accuracy of 95.1 ± 1.9 %. The proposed method for control of assistive devices was evaluated using a test in which a computer simulation model of an electric wheelchair was controlled using six tongue motions. This interface system, which weighs only 13.6 g and which has a simple appearance, requires no installation of any sensor into the mouth cavity. Therefore, it does not hinder user activities such as swallowing, chewing, or talking. The number of tongue motions is sufficient for the control of most assistive devices.

Modeling a powered wheelchair with slipping and gravitational disturbances on inclined and non-inclined surfaces

Wheelchairs are broadly accepted and are widespread because of the assistance they provide to people with limited mobility. The design of a good controller generally involves the formulation of a comprehensive wheelchair model. Most dynamic models in the literature presume non-inclined planer surfaces within-doors, and therefore fail to take the combined effects of both gravitational forces and rolling friction on the usable-traction into consideration. Wheel-slip situations are also commonly neglected. This paper contributes to wheelchair modeling by proposing and formulating a dynamic model that considers the effects of rolling friction and gravitational potential on the wheelchair’s road-load force, on both inclined and non-inclined surfaces. The dynamic model is derived through the Euler Lagrange procedure, and wheel slip is determined by an approach that reduces the convectional number of slip-detection encoders. In the closed-loop model, the input-output feedback controller is proposed for tracking the user inputs by torque compensation. The optimality of the resulting minimum-phase closed-loop system is then ensured through the performance index of the non-linear continuous-time generalized predictive control with good simulation results.

Measurement of wheelchair contact force with a low cost bench test

In mechanical engineering, it is well established that contact between the tire and the ground is a key parameter in characterizing the dynamic behavior of vehicles and an important factor in design control. Therefore, it is an important part of dynamic simulation models for vehicles, including wheelchairs. This work presents a bench test designed to experimentally monitor and measure the forces transmitted to the ground by a moving wheel. The test bench is composed of a table and a track with a fixed wheel structure and powertrain system. The table is an integrated structure that measures the longitudinal and lateral forces produced by tire contact. This table allows characterization of the tire and tests the tire under varying loads at different slip and camber angles. Additionally, the test bench can also be used to evaluate other tires, such as caster tires. The performances of the new device are illustrated, and the results show the differences between tires, which are related to the dynamic behaviors of wheelchair model. Finally, preliminary experiments performed using the test bench have shown that it is able to monitor and measure the forces generated by the contact between the tire and the ground.

Design And Structural Analysis Of A Powered Wheelchair Transmission

Abstract In this paper are presented the author’s researches on designing, dynamical and structural evaluation of a transmission for a wheelchair, intended to persons with locomotors disabilities. The kinematics of proposed transmission is analyzed in order to realize a proper synthesis and design of gears. A 3D model of the transmission and wheelchair are designed in Solid Works, and they will be used for the dynamic simulation of the wheelchair robotic system in Adams software. In Adams is analyzed wheelchair trajectory and dynamics for a combined trajectory: linear motion and steering. Dynamic parameters obtained from simulation are used to perform a finite element analysis of bevel and worm gears. Simulation results reveal the transmission dynamics parameters, emphasize the efficiency of the transmission and enable implementation of this design to a wheelchair model.

A brain computer interface for robust wheelchair control application based on pseudorandom code modulated Visual Evoked Potential.

In this pilot study, a novel and minimalistic Brain Computer Interface (BCI) based wheelchair control application was developed. The system was based on pseudorandom code modulated Visual Evoked Potentials (c-VEPs). The visual stimuli in the scheme were generated based on the Gold code, and the VEPs were recognized and classified using subject-specific algorithms. The system provided the ability of controlling a wheelchair model (LEGO(®) MINDSTORM(®) EV3 robot) in 4 different directions based on the elicited c-VEPs. Ten healthy subjects were evaluated in testing the system where an average accuracy of 97% was achieved. The promising results illustrate the potential of this approach when considering a real wheelchair application.

Development of an Adaptive KIT for Wheelchair Turning it into an Electric Tricycle

The wheelchair is one of the most used equipment for moving people with motion deficit in the lower limbs. The objective of this work was to design a KIT adaptable to a conventional wheelchair, turning it into an electric tricycle, in order to facilitate the movement of wheelchair users. This KIT enables the adaptive wheelchair travel greater distances in less time, making more quality of life. A structure was designed to fit in a conventional wheelchair, with the aid of CAD tools. This structure is sized to be able to withstand the stresses to which it is submitted. The adaptive KIT presented in this work can be used in a wide variety of models of wheelchairs and is functional, safe, and economically viable.

Robust Controller Design Of A Wheelchair Mobile Via Lmi Approach To Erp Systems With Feedback Output

This article discusses the design of robust controller applied to Wheelchair Furniture via Linear Matrix Inequalities (LMI), to obtain Strictly Positive Real (SPR) systems. The contributions of this work were the choice of a mathematical model for wheelchair: mobile with uncertainty about the position of the center of gravity (CG), the decoupling of the kinematic and dynamical systems, linearization of the models, the headquarters building of parametric uncertainties, the proposal of the control loop and control law with a specified decay rate.

Wheelchair Models With Integrated Transfer Support Mechanisms and Passive Actuation

The concept presented in this paper describes two new approaches to integrate transfer support functions into wheelchairs. The goal is to relieve caregivers and nurses in their daily task of lifting patients from and to the wheelchair without the need of an additional external lift device, such as commonly used lifting cranes or lifting belts. The contributions of this paper are (i) the design of two different mechanical linkages, which realize two types of transfer motions, (ii) the selection of a passive actuator for weight compensation and simulation of the force induced by it (static design), as well as (iii) the experimental evaluation of the simulation using rapid prototyping functional models of the concepts. The results are two different design concepts, each of which can realize a particular, smooth transfer motion.

Implementation of Fuzzy Logic Controller for Wheelchair Motion Control Based on EOG Data

The study of this paper is to implementation the fuzzy logic control designed for wheelchair motion based on the eye movement signals using electrooculograhphy (EOG) technique. This technique is to acquire the eye movement data from a person, for example, tetraplegia. The tetraplegia is paralysis caused by illness or injury to a human that result in the partial or total loss of use of all their limbs and torso. The eye movement data which was obtained can be used as a main communication tool between human and machine. The PD-type fuzzy controller was successfully designed and tested on the wheelchair model, for control the linear motion (focused for forward motion). The wheelchair model was developed using MSC.Visual Nastran 4D. The results obtained show that the PD-type fuzzy logic controller designed has successfully managed to track the input reference for linear motion set by the EOG signal.

A Prototype Design of Wireless Voice-Controlled Power Wheelchair Model with Emergency System

A Prototype Design of Wireless Voice-Controlled Power Wheelchair Model with Emergency System

Simulation model of a lever-propelled wheelchair.

Wheelchair efficiency depends significantly on the individual adjustment of the wheelchair propulsion interface. Wheelchair prescription involves reconfiguring the wheelchair to optimize it for specific user characteristics. Wheelchair tuning procedure is a complicated task that is performed usually by experienced rehabilitation engineers. In this study, we report initial results from the development of a musculoskeletal model of the wheelchair lever propulsion. Such a model could be used for the development of new advanced wheelchair approaches that allow wheelchair designers and practitioners to explore virtually, on a computer, the effects of the intended settings of the lever-propulsion interface. To investigate the lever-propulsion process, we carried out wheelchair lever propulsion experiments where joint angle, lever angle and three-directional forces and moments applied to the lever were recorded during the execution of defined propulsion motions. Kinematic and dynamic features of lever propulsion motions were extracted from the recorded data to be used for the model development. Five healthy male adults took part in these initial experiments. The analysis of the collected kinematic and dynamic motion parameters showed that lever propulsion is realized by a cyclical three-dimensional motion of upper extremities and that joint torque for propulsion is maintained within a certain range. The synthesized propulsion model was verified by computer simulation where the measured lever-angles were compared with the angles generated by the developed model simulation. Joint torque amplitudes were used to impose the torque limitation to the model joints. The results evidenced that the developed model can simulate successfully basic lever propulsion tasks such as pushing and pulling the lever.

Analysis of the influence of an articulated seat position for wheelchair on the pressure distribution in the gluteal region

INTRODUCTION: The present study proposes a new scientific project for the seat of a wheelchair, suggesting that, through the properties of a three plan mobile seat, the pelvis of individuals with neuromotor dysfunctions may position themselves adequately, allowing a chain effect, with innumerable benefits to the users, such as prevention of deformities, of muscle shortening, of pressure ulcers and improved functionality. In spite of innumerable wheelchair models available in market, none presents the ample properties resembling the articulated seat, allowing the pelvic alignment that is crucial for the adoption of an adequate posture. METHODS: The articulated seat was set over a ball and socket articulation made of two components, one convex that is fixed in the chair's structure and the other concave, attached to a mobile platform. The property of the articulated seat, to change the pressure distribution in the gluteal region, was tested on 34 typical individuals, without neurological injury, through a measurement system composed by 27 sensors. RESULTS: The significance of the statistic model proposed determined that the articulated seat was capable of altering the pressure distribution in the gluteal region in several positions on the frontal and sagittal planes, in healthy subjects. CONCLUSION: Despite the fact that this equipment is capable of redistributing the pressure in a seating position, future research to examine other parameters such as time of use, the use in subjects with neurological dysfunction, the angle of pelvic inclination, the criterions of indication and non-indication, inter alia, must be conducted to appropriately qualify this device.

Design of Individualized Wheelchairs Using AHP and Kano Model

To study how to design different grades of individualized wheelchairs according to users' needs, a personalized wheelchair design method based on AHP and Kano model is proposed. The AHP model determines the relative importance of characteristics of customers' demands. The subfunctions of manual wheelchairs and their attributes are given. The weight coefficients are calculated. 20 experts (10 are the members of the research team, 5 are doctors, and 5 are wheelchair designers) are involved in the above two parts of the work. Kano model represents the types of user requirements. 30 participants' (wheelchair users) needs are divided into 5 categories: M, O, E, I, and R. According to the types of user needs and the weight of each subfunction, three manual wheelchair models are built. Traditional design method usually cannot satisfy the requirements of users and product structure, so this paper makes a contribution to solve this problem. The method can be used to design individualized wheelchairs which may improve the product quality and customers' satisfaction. Meanwhile it also can reduce the design time, thereby reducing the design cost.

Evaluation of lightweight wheelchairs using ANSI/RESNA testing standards

Lightweight wheelchairs are characterized by their low cost and limited range of adjustment. Our study evaluated three different folding lightweight wheelchair models using the American National Standards Institute/Rehabilitation Engineering Society of North America (ANSI/RESNA) standards to see whether quality had improved since the previous data were reported. On the basis of reports of increasing breakdown rates in the community, we hypothesized that the quality of these wheelchairs had declined. Seven of the nine wheelchairs tested failed to pass the multidrum test durability requirements. An average of 194,502 +/- 172,668 equivalent cycles was completed, which is similar to the previous test results and far below the 400,000 minimum required to pass the ANSI/RESNA requirements. This was also significantly worse than the test results for aluminum ultralight folding wheelchairs. Overall, our results uncovered some disturbing issues with these wheelchairs and suggest that manufacturers should put more effort into this category to improve quality. To improve the durability of lightweight wheelchairs, we suggested that stronger regulations be developed that require wheelchairs to be tested by independent and certified test laboratories. We also proposed a wheelchair rating system based on the National Highway Transportation Safety Administration vehicle crash ratings to assist clinicians and end users when comparing the durability of different wheelchairs.

Analysis of different EOG-based eye movement strength levels for wheelchair control

This paper is aimed to analyse different levels of eye movement signals strength using Electrooculography (EOG). The eye movement is a potential communication tool for a tetraplegia, which is defined as a paralysis that is caused by serious injuries or illness to a human that lead to a partial or total loss of their lower limb and torso. The signal from the eye muscles that is called electrooculogram is generated at different eye movements’ directions and levels using g.USBamp from G.TEC Medical Engineering by using Ag/AgCl electrodes. Different directions and strength levels of eye movement are fed to Matlab-Simulink environment that was integrated with a virtual wheelchair model to study the effect of the EOG signals on the distance and rotation travelled by the wheelchair. Simulation results show that the EOG signals with different strengths acquired can be used as a reference input for wheelchair control.

Control of a stair climbing wheelchair

This paper presents investigations into the control of a stair climbing wheelchair particularly for indoor usage. A virtual wheelchair model is developed using Visual Nastran software and linked with Matlab/Simulink for control purposes. The goals are to have a simple, compact and stable stairs climbing wheelchair in order to complete the ascending and descending tasks. The challenges are to ensure the wheelchair seat always stay at the upright position and to control both the front and rear wheel motors while climbing. PID control is used to provide appropriate torque to both front and rear wheels as well as at to the wheelchair seat during climbing. Results show that the wheelchair movement can be controlled smoothly and the seat maintained at the desired position with the adapted approach.

Comparative ergonomic assessment of manual wheelchairs by paraplegic users

Purpose: The aim of the present study was to describe and test the reliability of a comprehensive product-centered approach to assessing functional performance and wheelchair user perceptions on device ergonomics and satisfaction of performance. A pilot study was implemented using this approach to evaluate differences among four manual wheelchairs. Method:. Six wheelchair users with complete spinal cord injury (SCI) at the thoracic level and with no previous upper limbs impairment were recruited for this study. After finishing circuit tasks, subjects were asked to complete a questionnaire about ergonomic wheelchair characteristics (manoeuvrability, stability, comfort and ease of propulsion) and satisfaction about task performance. On the other hand, objective data were recorded during user performance as the time required to complete each test, kinetic wheelchair propulsion data obtained with two SMARTWheels® and physiological parameters (heart rate and physiological index). Results: Kuschall Champion® and Otto Bock Voyage® wheelchairs were ranked best for most ergonomic aspects specially in manoeuvrability (p < 0.05). Less time was required to execute most of the circuit tasks in both wheelchair models (p < 0.05). Conclusions: This approach proposed highlight the importance of looking both kinds of information, user perception and user functional performance when evaluating a wheelchair or comparing across devices.Implications for RehabilitationIn rehabilitation, the reliability of the clinical evaluation of the wheelchair can help to improve and adapt the wheelchair to patient, contributing significantly to the prevention of overuse injuries in the upper limbs.

EVOLUTIONARY TUNING OF MODULAR FUZZY CONTROLLER FOR TWO-WHEELED WHEELCHAIR

In this work, an optimization technique is adopted to manipulate the input and output scaling factors of a modular fuzzy logic controller (MFC) for lifting and stabilizing the front wheels of a wheelchair in two-wheeled mode. A virtual wheelchair (WC) model is developed within Visual Nastran (VN) software environment where the model is further linked with Matlab/Simulink for control purposes. The lifting of the chair is done by transforming the first link (Link1), attached to the front wheels (casters) to the upright position while maintaining stability of the second link (Link2) where the payload is attached. General rules of thumb allow heuristic tuning (trial and error) of the parameters but such heuristic method does not guarantee that the system tuned with current data set will represent future system states. A global optimization mechanism such as genetic algorithm is necessary to improve the system performance. Due to its significant advantages over other searching methods, a genetic algorithm approach is used to optimize the scaling factors of the MFC and results show that the optimized parameters give better system performance for such a complex, highly nonlinear two-wheeled wheelchair system.