Wheelchair.q, a mechanical concept for a stair climbing wheelchair

This paper present Wheelchair.q, a concept for a stair climbing wheelchair able to move in structured and unstructured environment, to climb over obstacles and to go up and down stairs. The wheelchair passively changes its locomotion, from a rolling on wheels to a stepping on legs one. The different locomotions are triggered only by local and dynamic conditions and not by an external command and so only one motor for each locomotion unit is necessary. A four-bar linkage moves and rotates the chair, in order to avoid wheelchair turning over and to guarantee a comfortable posture to the passenger.