A legged mobile robot controls the posture of the body thereof in a stable manner
using a ZMP stability determination criterion with a relatively long sampling period.
The legged mobile robot has a stable ZMP region which is a supporting polygon formed
of the ground contact point of a sole of a movable leg and a walking surface, and
a ZMP behavior space in which a momentum of the robot body is generated so that
the ZMP shifts to the approximate center of the stable ZMP region. In the ZMP behavior
space, the momentum of the robot shifts in a positive direction or in a negative
direction. In the negative direction, a space distortion shifts the ZMP to the
periphery of the stable region, and in the positive direction, a space distortion
shifts the ZMP to the center of the stable region.
