On the Improvement of Multi-Legged Locomotion over Difficult Terrains Using a Balance Stabilization Method

This paper deals with the real-time walking of a multi-legged robot over difficult terrains using a balance stabilization method in order to achieve a fast speed and robust locomotion with minimal tracking errors. The stabilization method is described through a ZMP-based online pattern-generation scheme inspired by bio-mimetic stepping leg transferences with an active balance control so as to reduce the propagation of instability while performing rapid stepping actions for a fast walking gait in the presence of external disturbances. The proposed control system uses a force-position controller 14 which takes impact dynamics into consideration to compensate for the effect of external perturbations during walking by estimating impulsive forces in real-time. Using the proposed stabilization method, the robot plans appropriate footholds on the ground in order to achieve a reasonable average walking speed over difficult terrains in a natural environment. The success and performance of the proposed method is realized through dynamic simulations and real-world experiments using a six-legged hexapod robot.