Turning characteristics and stability of manual wheelchairs on a slope

Wheelchairs will be in ever greater demand in a rapidly aging society. Because of the special needs of aging users, due to frailty and reduced reflexes in many cases, it is important to give careful consideration to rather fundamental design properties. Inter alia it is very important to define, clarify and design running, turning and stability properties of the highest standards in manual wheelchairs. In particular we discuss these matters in regard to wheelchair behavior on sloping surfaces. In the present paper we report on an analytical model for a 4 wheel manual wheelchair which shows good correlation with the existing experimental data relating to torque and speed when the wheelchair is moving on a level plane and when climbing a 3 degree slope. The rolling stability of the wheelchair on a slope is also discussed.