Design of a battery powered wheelchair

Abstract

The aim of this project is to design a battery operated wheelchair. The design featured is a wheelchair with the basic requirements for an invalid having enough strength in the arms to operate handlevers (requiring around 45 N max.). The chair is intended for use both indoors and outdoors. The design procedure involves the determination of a centre of gravity position for both chair and occupant from which calculations may be initiated. At this stage the chair stability is analysed. This is followed by the design of the shafts and the determination of the type and size of bearings required for both front and rear wheels. A coil-spring suspension is also incorporated to enable a comfortable ride. With safety as a first priority, a braking system is designed for manual operation. The steering of the wheelchair is also designed for manual operation, however, provision for electrically controlled steering is also described. Finally, a reference to British Standards specifications is made for strength and stability tests to be carried out on a prototype wheelchair.