This paper proposes a control method for walking robots by manipulating the zero moment point of the motion. The control law is developed based on a simple model, in which motion of a point mass in a sagital plane is governed by the gravitation and reaction force from the ground. Stability of the system under the control is analyzed by using the state plots of the motion trajectory.
The objective of the control method is to control the balance of the robot without depending on the strict tracking control, which is required, in conventional methods, in order to prevent the robot from falling down.