Evolution of Wheelchair.q, a Stair-climbing Wheelchair

This paper presents a solution for a stair-climbing wheelchair that can climb single steps or entire staircases. This device was designed in order to ensure greater autonomy for people with reduced mobility. The main component of the wheelchair structure is a three-wheel locomotion unit that allows obstacle climbing thanks to an epicycloidal transmission. The other characteristic element is an idle track that behaves like a second foothold giving static stability during stair-climbing. Another important feature concerned with this design is a reconfiguration mechanism that makes the wheelchair suitable both for stair-climbing and for moving on flat ground. This feature allows performances and overall dimensions comparable to traditional electric wheelchairs. The choice and design of the mechanisms for the reconfiguration phase are the main topics discussed in this article and represent the principal innovations of this wheelchair compared to earlier versions.