%A Sprowitz,Alexander %A ajallooeian,Mostafa %A Tuleu,Alexandre %A Ijspeert,Auke %D 2014 %J Frontiers in Computational Neuroscience %C %F %G English %K motion primitives,locomotion patterns,central pattern generator,quadruped robot,in-series and in-parallel leg compliance,entrainment,Coupled oscillators,lateral sequence walk,trot %Q %R 10.3389/fncom.2014.00027 %W %L %M %P %7 %8 2014-March-07 %9 Original Research %+ Dr Alexander Sprowitz,ÉCOLE POLYTECHNIQUE FÉDÉRALE DE LAUSANNE,Lausanne,Switzerland,sprowitz@is.mpg.de %# %! Kinematic primitives for walking and trotting gaits of a quadruped robot with compliant legs %* %< %T Kinematic primitives for walking and trotting gaits of a quadruped robot with compliant legs %U https://www.frontiersin.org/articles/10.3389/fncom.2014.00027 %V 8 %0 JOURNAL ARTICLE %@ 1662-5188 %X In this work we research the role of body dynamics in the complexity of kinematic patterns in a quadruped robot with compliant legs. Two gait patterns, lateral sequence walk and trot, along with leg length control patterns of different complexity were implemented in a modular, feed-forward locomotion controller. The controller was tested on a small, quadruped robot with compliant, segmented leg design, and led to self-stable and self-stabilizing robot locomotion. In-air stepping and on-ground locomotion leg kinematics were recorded, and the number and shapes of motion primitives accounting for 95% of the variance of kinematic leg data were extracted. This revealed that kinematic patterns resulting from feed-forward control had a lower complexity (in-air stepping, 2–3 primitives) than kinematic patterns from on-ground locomotion (νm4 primitives), although both experiments applied identical motor patterns. The complexity of on-ground kinematic patterns had increased, through ground contact and mechanical entrainment. The complexity of observed kinematic on-ground data matches those reported from level-ground locomotion data of legged animals. Results indicate that a very low complexity of modular, rhythmic, feed-forward motor control is sufficient for level-ground locomotion in combination with passive compliant legged hardware.