Abstract
In this paper, a walker that enables disabled or elderly people to rehabilitate outdoors is proposed. This walker has a pair of rotary cross arms with passive wheels, which allow the body to get over steps. Each arm begins to rotate automatically if the angle of the arm is over the threshold. The user can travel safely because this walker are passive and cannot move unintentionally with driving force. The walker has a small turning circle because the rotary cross arms with wheels are located in front of the body; therefore it has good maneuverability. This paper presents the conceptual design of the walker and the control of the rotary cross arm with passive wheels when getting over a step. The maneuverability of the walker is also discussed. The experimental results of the prototype confirm the design effectiveness.
