Initial results in the development of a guidance system for a powered wheelchair

Three-dimensional modelling of wheelchair contrived with lower limb exoskeleton for right hemiplegic dysfunction

Hemiplegia is a type of paralysis that affects one side of the body due to stroke, characterizing severe weakness or rigid movement. Many people of different age groups are affected by this condition which cannot be completely cured but can be minimized through proper physiotherapy. A continuous and repeated exercise has to be given to the hemiplegic subjects to regain their motor function. To serve this purpose, a three-dimensional model of wheelchair contrived with lower limb exoskeleton is designed and motion analysis is done using SolidWorks. This virtual model of the object is created with the assistance of computer-aided design software. Professionals can be able to do the experiment on what-if scenarios with their three-dimensional designs, which helps to validate their devices and identify any snags with design quality. The pattern of behaviour of lower limb exoskeleton is predicted using SimMechanics in MATLAB.

Dynamic control of a reconfigurable stair-climbing mobility system

Electric-powered wheelchairs improve the mobility of people with physical disabilities, but the problem to deal with certain architectural barriers has not been resolved satisfactorily. In order to solve this problem, a stair-climbing mobility system (SCMS) was developed. This paper presents a practical dynamic control system that allows the SCMS to exhibit a successful climbing process when faced with typical architectural barriers such as curbs, ramps, or staircases. The implemented control system depicts high simplicity, computational efficiency, and the possibility of an easy implementation in a microprocessor-/microcontroller-based system. Finally, experiments are included to support theoretical results.

Collaborative path planning for a robotic wheelchair

Generating a path to guide a wheelchair's motion faces two challenges. First, the path is located in the human environment and that is usually unstructured and dynamic. Thus, it is difficult to generate a reliable map and plan paths on it by artificial intelligence. Second, the wheelchair, whose task is to carry a human user, should move on a smooth and comfortable path adapted to the user's intentions. To meet these challenges, we propose that the human operator and the robot interact to create and gradually improve a guide path. This paper introduces design tools to enable an intuitive interaction, and reports experiments performed with healthy subjects in order to investigate this collaborative path learning strategy. We analyzed features of the optimal paths and user evaluation in representative conditions. This was complemented by a questionnaire filled out by the subjects after the experiments. The results demonstrate the effectiveness of this approach, and show the utility and complementarity of the tools to design ergonomic guide paths.

Trends and issues in wheelchair technologies

There is an overwhelming need for wheelchairs and the research and development required to make them safer, more effective, and widely available. The following areas are of particular importance: practitioner credentials, accreditation, device evaluation, device user training, patient education, clinical prescribing criteria, national contracts, and access to new technology. There are over 170 U.S. wheelchair manufacturers with a total reported income of $1.33 billion. However, of these companies, only five had sales in excess of $100 million. Wheelchairs account for about 1% of Medicare spending. Use of assistive technology is an increasingly common way of adapting to a disability. The emergence of advanced mobility devices shows promise for the contribution of engineering to the amelioration of mobility impairments for millions of people who have disabilities or who are elderly. Some of the trends in wheelchairs are going to require new service delivery mechanisms, changes to public policy, and certainly greater coordination between consumers, policy makers, manufacturers, researchers, and service providers.

Engineering better wheelchairs to enhance community participation

With about 2.2 million Americans currently using wheeled mobility devices, wheelchairs are frequently provided to people with impaired mobility to provide accessibility to the community. Individuals with spinal cord injuries, arthritis, balance disorders, and other conditions or diseases are typical users of wheelchairs. However, secondary injuries and wheelchair-related accidents are risks introduced by wheelchairs. Research is underway to advance wheelchair design to prevent or accommodate secondary injuries related to propulsion and transfer biomechanics, while improving safe, functional performance and accessibility to the community. This paper summarizes research and development underway aimed at enhancing safety and optimizing wheelchair design.

Utilization of ultrasound sensors for anti-collision systems of powered wheelchairs

Anti-collision systems have been developed for use with powered wheelchairs in order to enable people with cognitive or physical impairments to safely operate a powered wheelchair. Anti-collision systems consist of sensors that have the ability to detect objects near the wheelchair and a computer that can stop the chair if a collision is determined to be likely. This investigation considered the suitability of using ultrasound sensors in such a system when encountering objects typically found within a home or a long-term care facility. An ultrasound sensor's ability to detect an object was dependent on the object's size, shape, specularity, reflectivity, and sound absorption characteristics. Ultrasound sensors, by themselves, were found to be unsuitable for anti-collision systems due to an inability to detect objects commonly encountered in the target environment (the home or long-term care facility) without increasing the complexity of the system to such a degree that it would be prohibitive to deploy this technology to the public.

The smart house for older persons and persons with physical disabilities: structure, technology arrangements, and perspectives

Smart houses are considered a good alternative for the independent life of older persons and persons with disabilities. Numerous intelligent devices, embedded into the home environment, can provide the resident with both movement assistance and 24-h health monitoring. Modern home-installed systems tend to be not only physically versatile in functionality but also emotionally human-friendly, i.e., they may be able to perform their functions without disturbing the user and without causing him/her any pain, inconvenience, or movement restriction, instead possibly providing him/her with comfort and pleasure. Through an extensive survey, this paper analyzes the building blocks of smart houses, with particular attention paid to the health monitoring subsystem as an important component, by addressing the basic requirements of various sensors implemented from both research and clinical perspectives. The paper will then discuss some important issues of the future development of an intelligent residential space with a human-friendly health monitoring functional system.

Integrated Control and Related Technology of Assistive Devices

Assistive devices are now available that allow persons with severe physical disabilities to complete tasks independently. When the user has severe physical limitations, it may be advantageous to have an integrated control system where a single control interface (e.g., joystick, head switches, voice recognition system, keypad) is used to operate two or more assistive devices (e.g., power wheelchairs, augmentative communication devices, computers, environmental control units, and other devices that are controlled electronically). The advantages of integrated control are that persons with limited motor control can access several devices with one access site without assistance, and the user does not need to learn a different operating mechanism for each device. The purpose of this review is to convey the depth and breadth of the research that has been conducted on integrated control systems, as well as to provide some insights into future directions. We reviewed research works pertaining to communication and environmental control, computer access, and wheelchair guidance systems. Information gathered in this study will help people become fully aware of the status of contemporary integrated control technology in order to increase the quality of life of people who use electronic assistive devices.

The NavChair Assistive Wheelchair Navigation System

The NavChair Assistive Wheelchair Navigation System [19] is being developed to reduce the cognitive and physical requirements of operating a power wheelchair for people with wide ranging impairments that limit their access to powered mobility. The NavChair is based on a commercial wheelchair system with the addition of a DOS-based computer system, ultrasonic sensors, and an interface module interposed between the joystick and power module of the wheelchair. The obstacle avoidance routines used by the NavChair in conjunction with the ultrasonic sensors are modifications of methods originally used in mobile robotics research. The NavChair currently employs three operating modes: general obstacle avoidance, door passage, and automatic wall following. Results from performance testing of these three operating modes demonstrate their functionality. In additional to advancing the technology of smart wheelchairs, the NavChair has application to the development and testing of "shared control" systems where a human and machine share control of a system and the machine can automatically adapt to human behaviors.