Passive wireless tags for tongue controlled assistive technology interfaces

Tongue control with low profile, passive mouth tags is demonstrated as a human–device interface by communicating values of tongue-tag separation over a wireless link. Confusion matrices are provided to demonstrate user accuracy in targeting by tongue position. Accuracy is found to increase dramatically after short training sequences with errors falling close to 1% in magnitude with zero missed targets. The rate at which users are able to learn accurate targeting with high accuracy indicates that this is an intuitive device to operate. The significance of the work is that innovative very unobtrusive, wireless tags can be used to provide intuitive human–computer interfaces based on low cost and disposable mouth mounted technology. With the development of an appropriate reading system, control of assistive devices such as computer mice or wheelchairs could be possible for tetraplegics and others who retain fine motor control capability of their tongues. The tags contain no battery and are intended to fit directly on the hard palate, detecting tongue position in the mouth with no need for tongue piercings

Review of Assistive Devices for Electric Powered Wheelchairs Navigation

The decreasing costs of microprocessor systems and increasing range of “Smart Sensors” have led to a boom in Assistive Device Technology. The annual rate of expenditure for mobility related devices has reached $1 billion dollars in the United States alone. The industries current focus is to develop a wider range of Independent Mobility Controllers to allow, even the most severely disabled person, the ability to control an Electric Powered Wheelchair (EPW). Advances in Autonomous Robot Design have led to corresponding improvements in EPW technology. This paper outlines user interfaces and input device technologies used at present to navigate an EPW

Preliminary evaluation of a 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 with 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 the VCJ in either 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

Overcoming barriers and increasing independence: service robots for elderly and disabled people

This paper discusses the potential for service robots to overcome barriers and increase independence of elderly and disabled people. It includes a brief overview of the existing uses of service robots by disabled and elderly people and advances in technology which will make new uses possible and provides suggestions for some of these new applications. The paper also considers the design and other conditions to be met for user acceptance. It also discusses the complementarity of assistive service robots and personal assistance and considers the types of applications and users for which service robots are and are not suitable

Estratégias de controle de trajetórias para cadeira de rodas robotizadas

Orientador: Eleri CardozoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de ComputaçãoResumo: Desde os anos 80, diversos trabalhos foram publicados com o objetivo de propor soluções alternativas para usuários de cadeira de rodas motorizadas com severa deficiência motora e que não possuam capacidade de operar um joystick mecânico. Dentre essas soluções estão interfaces assistivas que auxiliam no comando da cadeira de rodas através de diversos mecanismos como expressões faciais, interfaces cérebro-computador, e rastreamento de olho. Além disso, as cadeiras de rodas ganharam certa autonomia para realizar determinadas tarefas que vão de desviar de obstáculos, abrir portas e até planejar e executar rotas. Para que estas tarefas possam ser executadas, é necessário que as cadeiras de rodas tenham estruturas não convencionais, habilidade de sensoriamento do ambiente e estratégias de controle de locomoção. O objetivo principal é disponibilizar uma cadeira de rodas que ofereça conforto ao usuário e que possua um condução segura não importando o tipo de deficiência do usuário. Entretanto, durante a condução da cadeira de rodas, o desalinhamento das rodas castores podem oferecer certo perigo ao usuário, uma vez que, dependendo da maneira em que elas estejam orientadas, instabilidades podem ocorrer, culminando em acidentes. Da mesma forma, o desalinhamento das rodas castores é considerado um dos principais causadores de desvios de trajetória que ocorrem durante a movimentação da cadeira de rodas, juntamente com diferentes distribuições de pesos ou diferentes atritos entre as rodas e o chão. Nesta dissertação, é considerado apenas o desalinhamento das rodas castores como único causador de desvio de trajetória da cadeira de rodas e, dessa forma, são propostas soluções que possam reduzir ou até mesmo eliminar o efeito deste desalinhamento. Com a implementação das melhores soluções desenvolvidas neste trabalho, é possível fazer com que diversas interfaces assistivas que têm baixa taxa de comandos possam ser utilizadas, uma vez que o usuário não precisa, constantemente, corrigir o desvio da trajetória desejada. Ademais, é elaborado um novo projeto de cadeira de rodas "inteligente" para a implementação das técnicas desenvolvidas neste trabalhoAbstract: Since the 1980s several works were published proposing alternative solutions for users of powered wheelchairs with severe mobility impairments and that are not able to operate a mechanical joystick. Such solutions commonly focus on assistive interfaces that help commanding the wheelchair through distinct mechanisms such as facial expressions, brain-computer interfaces, and eye tracking. Besides that, the wheelchairs have achieved a certain level of autonomy to accomplish determined tasks such as obstacle avoidance, doors opening and even path planning and execution. For these tasks to be performed, it is necessary the wheelchairs to have a non conventional designs, ability to sense the environment and locomotion control strategies. The ultimate objective is to offer a comfortable and safe conduction no matter the user's mobility impairments. However, while driving the wheelchair, the caster wheels' misalignment might offer risks to the user, because, depending on the way they are initially oriented, instabilities may occur causing accidents. Similarly, the caster wheels' misalignment can be considered, among others like different weight distribution or different friction between wheel and floor, one of the main causes of path deviation from the intended trajectory while the wheelchair is moving. In this dissertation, it is considered the caster wheels' misalignment as the unique generator of wheelchair path deviation and, therefore, it is proposed different solutions in order to reduce or even eliminate the effects of the misalignment. The implementation of the best solutions developed in this work allows assistive interfaces with low rate of commands to be widespread, once the user does not need to, constantly, correct path deviation. Additionally, a new smart wheelchair project is elaborated for the implementation of the techniques developed in this workMestradoEngenharia de ComputaçãoMestre em Engenharia Elétrica88882.329382/2019-01CAPE

DEVELOPMENT AND EVALUATION OF AN ADVANCED REAL-TIME ELECTRICAL POWERED WHEELCHAIR CONTROLLER

Advances in Electric Powered Wheelchairs (EPW) have improved mobility for people with disabilities as well as older adults, and have enhanced their integration into society. Some of the issues still present in EPW lie in the difficulties when encountering different types of terrain, and access to higher or low surfaces. To this end, an advanced real-time electrical powered wheelchair controller was developed. The controller was comprised of a hardware platform with sensors measuring the speed of the driving, caster wheels and the acceleration, with a single board computer for implementing the control algorithms in real-time, a multi-layer software architecture, and modular design. A model based real-time speed and traction controller was developed and validated by simulation. The controller was then evaluated via driving over four different surfaces at three specified speeds. Experimental results showed that model based control performed best on all surfaces across the speeds compared to PID (proportional-integral-derivative) and Open Loop control. A real-time slip detection and traction control algorithm was further developed and evaluated by driving the EPW over five different surfaces at three speeds. Results showed that the performance of anti-slip control was consistent on the varying surfaces at different speeds. The controller was also tested on a front wheel drive EPW to evaluate a forwarding tipping detection and prevention algorithm. Experimental results showed that the tipping could be accurately detected as it was happening and the performance of the tipping prevention strategy was consistent on the slope across different speeds. A terrain-dependent EPW user assistance system was developed based on the controller. Driving rules for wet tile, gravel, slopes and grass were developed and validated by 10 people without physical disabilities. The controller was also adapted to the Personal Mobility and Manipulation Appliance (PerMMA) Generation II, which is an advanced power wheelchair with a flexible mobile base, allowing it to adjust the positions of each of the four casters and two driving wheels. Simulations of the PerMMA Gen II system showed that the mobile base controller was able to climb up to 8” curb and maintain passenger’s posture in a comfort position

A reconfigurable wheelchair for mobility and rehabilitation:Design and development

This paper presents the design and development of a prototype of a reconfigurable wheelchair for rehabilitation and self-assistance to fit the size of a seven years old child (average 35 kg weight). Though the developed prototype is developed at this stage to fit a child, it can be resized, after considering variations in weight and size, to fit an older adult. The developed prototype has a mechanism that enables the user to transform from sit-to-stand (STS) posture and vice versa. With the help of the developed wheelchair, the user will also be able to adjust the posture of his upper body using an adjustable back support using two linear actuators. This configuration will allow the user to use the wheelchair as a mobility device as well as for rehabilitation purposes without the need of external support. The availability of STS and back adjustment mechanisms will allow the user to do regular exercising which will enhance blood circulation as sitting for long periods inflates lower limbs disability. The proposed configuration will help in enhancing the functional capabilities of end-users allowing for increased independence and ultimately quality of life

A Dynamic Localized Adjustable Force Field Method for Real-time Assistive Non-holonomic Mobile Robotics

Providing an assistive navigation system that augments rather than usurps user control of a powered wheelchair represents a significant technical challenge. This paper evaluates an assistive collision avoidance method for a powered wheelchair that allows the user to navigate safely whilst maintaining their overall governance of the platform motion. The paper shows that by shaping, switching and adjusting localized potential fields we are able to negotiate different obstacles by generating a more intuitively natural trajectory, one that does not deviate significantly from the operator in the loop desired-trajectory. It can also be seen that this method does not suffer from the local minima problem, or narrow corridor and proximity oscillation, which are common problems that occur when using potential fields. Furthermore this localized method enables the robotic platform to pass very close to obstacles, such as when negotiating a narrow passage or doorway