Steering control of piggyback type wheelchair using avoidance intension detected by weight shift

Recently, electric wheelchair STAVi that is a welfare vehicle has been developed to use indoors as well as outdoors. It is easy for a disabled person to climb into this wheelchair from a bed because they can do so by piggybacking from a bed or chair. This wheelchair is manipulated by a joystick in order to make driving easier. Further driver´s posture is kept by the armrests for safety. In the narrow corridors, the passers sometimes dash out from the doors or corners. It is well known that electric wheelchairs do not have mechanical brakes. So, the avoidance steering must be sophisticated in addition to the decelerating for quick avoidance in accidental situations. In this paper, we propose steering assistance method by the weight shift using Modeling Error Compensator (MEC). The center of gravity (COG) is controlled by driver´s weight shift so as to enhance the avoidance intention. The effectiveness of proposed method is evaluated by experiments.