Abstract
Due to pathologies or age-related problems, in some disabled people, motor impairment is associated with cognitive and/or visual impairments. This combination of limitations unfortunately leads to an inability to move around independently. Indeed, their situation does not allow them to use a conventional electric wheelchair, for safety reasons, and for the moment there is no other technological solution providing safe movement capacity. This lack of access to an autonomous travel solution has the consequence of weakening the intellectual, personal, social, cultural and moral development, as well as the life expectancy, of the people concerned. In this context, our team is working on the development of an optoelectronic system that secures the displacement of electric wheelchairs. This is a large project that requires the development of several functionalities such as: the anti-collision of the wheelchair with its environment, the prevention of falls from the wheelchair on uneven levels, and the adaptation of the system mechanically and electronically to the majority of commercially available electric wheelchair models, among others. In this article, we introduce our solution for detecting dangerous height differences, also called “negative obstacles”, through the creation of a dedicated sensor. This sensor works by optical triangulation and can embed several laser beams in order to extend its detection zone. It has the particularity of being robust in direct sunlight and rain and has a sufficiently high measurement rate to be suitable for the displacement of electric wheelchairs. We develop an adapted algorithm, and point out compromises, in particular between the orientation of the laser beams and the maximal speed of the wheelchair.
Highlights
Whether it is due to age-related problems, a congenital disability or an accident, some people possess a combination of impairments that do not allow them to move independently
Our goal was to combine the qualities of laser detection: energy concentrated at a point allowing a good signal-to-noise ratio, satisfactory measurement accuracy, and low energy consumption, while bypassing its shortcomings, namely its punctual nature, which does not allow surface detection
Following the presentation of the method of determination of the position of the backscattered laser spot, we focus on the evolution of its position as a function of time and on the progress of the electric wheelchair
Summary
Whether it is due to age-related problems, a congenital disability or an accident, some people possess a combination of impairments that do not allow them to move independently This combination is often of a motor nature, in addition to impaired cognition and/or visual field. There is no technical solution to meet their needs in order to allow them to travel in complete safety They find themselves in a passive displacement situation and require assistance from a caregiver or a family member. A representative case for this type of situation ( not exclusive) is people with cerebral palsy This pathology is likely to cause uncontrolled movements, a limitation of gestures, and visual impairment or cognitive problems for the people concerned. The expression of this pathology is specific to each person, with respect to both the nature of the impairments encountered and their severity
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