Essay On Wheelchair Disability

Wheelchair prevalence could be linked to the role they play in alleviating mobility restrictions over short distances. According to the South African profile report of persons with disability \citep{StatisticsSouthAfrica2014}, 2.3\% ($\approx 1.2$ million) of the total South African population ($\approx 52$ million) depend on the wheelchair. Moreover, the percentage of people in need of wheelchairs could be much higher in other underdeveloped countries because diseases responsible for mobility impairments like cerebral palsy can be associated with lower socio-economic status \citep{Sundrum2005}. While this may seem to represent a marginal portion of the population, it may not be possible to over emphasise the important sense of independence and self-esteem, that users with debilitating impairments experience with wheelchairs. It may be noted in the absence the wheelchairs and other mobility aids, that ambulatory impairments may result extreme emotional loss, neglect, stress and even isolation \citep{Finlayson2003}.

%In the absence of such mobility aids, the potential users may suffer extreme emotional loss, neglect, stress and even isolation \citep{Finlayson2003}.

It is important that the actual behaviour of the wheelchair is represented as much as possible by the model. In literature, the modelling of differential drive wheelchairs is carried out from both kinematics and dynamic perspectives. The kinematic models present ideal formulations that relate the wheel rates of the wheelchair to the body-fixed frame velocities, by considering the geometric properties. However, kinematic models do not account for the effects of mass, inertia and acceleration, and are therefore used with anticipation that the controller will be robust enough to account for the unconsidered dynamical properties