US Patent 8151912 Wheeled inverted pendulum mobile unit

A wheeled inverted pendulum mobile unit having: a driving wheel; a body that is tiltable about an axle of the driving wheel with respect to a vertical direction; a plurality of support members that extend downward from the body in the vertical direction, wherein the bottom ends of the plurality of support members are in contact with a ground before and behind the axle of the driving wheel, and the bottom ends moves up and down, with respect to the body, as the body tilts with respect to the vertical direction; and a lock mechanism that locks positions of the bottom ends of the support members with respect to the body.