Zero moment point

The zero moment point (also referred to as zero-tilting moment point) is a concept related to the dynamics and control of legged locomotion, e.g., for humanoid or quadrupedal robots. It specifies the point with respect to which reaction forces at the contacts between the feet and the ground do not produce any moment in the horizontal direction, i.e., the point where the sum of horizontal inertia and gravity forces is zero. The concept assumes the contact area is planar and has sufficiently high friction to keep the feet from sliding.