Online walking gait generation with predefined variable height of the center of mass

Abstract

For biped robots one main issue is the generation of stable trajectories for the center of mass (CoM). Several different approaches based on the zero moment point (ZMP) scheme have been presented in the past. Due to the complex dynamic structure of bipedal robots, most of the considered algorithms use a simplified time invariant linear model to approximate the dynamics of the system. This model is extended to a time variant one and then used to generate stable CoM trajectories with variable predefined CoM height. This allows to generate trajectories online for walking underneath obstacles with more accuracy. It is shown that using this extended scheme it is possible to overcome some kinematic limits as joint speed in the knee or the maximum step length for common walking. © 2011 Springer-Verlag.