US Patent 8014923 Travel device

A travel device includes a plurality of wheels disposed parallel to one another, a step plate mounted between the wheels, a handle mounted to the step plate, and a driving motor that allows the step plate and handle to tilt in a roll axis direction. The device further includes a control unit that drives the motor so as to maintain the step plate horizontal or the handle vertical. The device also includes a measurement unit that measures a shift operation of the step plate or the handle. The plurality of wheels may change direction based on the value determined by the measuring unit.