Analysis and optimization of lever propelled wheelchair

Abstract

A wheelchair is a commonly used assistive device used by disabled people for mobility. An appropriate wheelchair gives them a sense of independence and encourages them to become productive members of the society. It gives them a feeling of belongingness and inclusion in the society. But for centuries now in India, there has been a clear vacuum of thoughts over a redesign of traditional wheelchairs. A new design of existing levered wheelchair is proposed here. This new design would increase the reach capabilities and social boundaries of disabled which inhibit the lives of the disabled day to day. The paper is divided into two parts. In the first part a comparative study has been done of push rim wheelchair and lever wheelchair. In the second part, Optimization of the lever wheelchair has been done. The comparison has been done on various parameters such as peak velocity, average velocity, acceleration, retardation, Stroke frequency, Reduction in effort, Mechanical efficiency, Obstacle climbing ability, Turning radius, the distance travelled per stroke, Pressure cuts and burns caused during propelling the chair. Biomechanical testing is also done considering the heart rate and oxygen level consumption. This information can be used to determine the energy demand, which is intrinsically connected to a wheelchair's mechanical efficiency. Feedback from test subjects was used for the optimization of the chair. The optimization mainly focus on the ergonomics and efficiency of design and for that the main emphasis is given on factors like the position of Lever-drive system, Configuration of wheel, chassis and Foot Rest. This optimized design would make the chair more efficient and easy to use by enabling the person to drive, steer, and stop without even touching the wheels, thus, eliminating the risk of friction burns and protecting the wrists and shoulders from repetitive stresses. The analysis is done using software like ANSYS and CATIA and validation of results is conducted with the users and non-users of wheel chair.